olmesartan/hydrochlorothiazide (Rx)

Hypertension

Initial: 20 mg/12.5 mg PO qDay

May increase to 40 mg/25 mg after 2 weeks

Renal Impairment

CrCl <30 mL/min: Not recommended

Hepatic Impairment

Dose adjustment not necessary

Safety and efficacy not established

Contraindicated (1)

• aliskiren

  olmesartan decreases effects of aliskiren by Other (see comment). Contraindicated. Comment: Aliskiren use contraindicated with ARBs in patients with diabetes; avoid coadministration with ARBs if GFR. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of ARBS with drugs that affect RAAS may increase the risk of renal impairment (including acute renal failure) and cause loss of antihypertensive effect. Monitor renal function periodically.

Serious - Use Alternative (23)

• aminolevulinic acid oral

  aminolevulinic acid oral, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  hydrochlorothiazide increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• benazepril

  olmesartan, benazepril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• captopril

  olmesartan, captopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• carbamazepine

  carbamazepine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of systemic hyponatremia.

• cyclophosphamide

  hydrochlorothiazide increases toxicity of cyclophosphamide by decreasing renal clearance. Avoid or Use Alternate Drug. Increased myelosuppressive effects.

• cyclosporine

  cyclosporine, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of systemic hyponatremia.

• dofetilide

  hydrochlorothiazide increases levels of dofetilide by decreasing renal clearance. Contraindicated. Risk of prolonged QTc interval.

• enalapril

  olmesartan, enalapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• fosinopril

  olmesartan, fosinopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• isocarboxazid

  isocarboxazid, hydrochlorothiazide. Other (see comment). Contraindicated. Comment: Additive hypotensive effects may be seen when MAOI's are combined with antihypertensives.

• lisinopril

  olmesartan, lisinopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• lithium

  olmesartan increases toxicity of lithium by decreasing renal clearance. Avoid or Use Alternate Drug.

• lofexidine

  lofexidine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that decrease pulse or blood pressure to mitigate risk of excessive bradycardia and hypotension.
  
  lofexidine, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that decrease pulse or blood pressure to mitigate risk of excessive bradycardia and hypotension.

• methyl aminolevulinate

  hydrochlorothiazide, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• moexipril

  olmesartan, moexipril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• perindopril

  olmesartan, perindopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• potassium phosphates, IV

  olmesartan and potassium phosphates, IV both increase serum potassium. Avoid or Use Alternate Drug.

• quinapril

  olmesartan, quinapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• ramipril

  olmesartan, ramipril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• squill

  hydrochlorothiazide increases toxicity of squill by Other (see comment). Avoid or Use Alternate Drug. Comment: Potassium depletion may enhance toxicity of squill.

• trandolapril

  olmesartan, trandolapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• tretinoin

  hydrochlorothiazide, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

Monitor Closely (221)

• acebutolol

  acebutolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and acebutolol both increase serum potassium. Use Caution/Monitor.
  
  acebutolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• aceclofenac

  olmesartan and aceclofenac both increase serum potassium. Use Caution/Monitor.
  
  aceclofenac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• acemetacin

  olmesartan and acemetacin both increase serum potassium. Use Caution/Monitor.
  
  acemetacin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• albiglutide

  hydrochlorothiazide decreases effects of albiglutide by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.
  
  olmesartan increases effects of albiglutide by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.

• albuterol

  albuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• aldesleukin

  aldesleukin increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• aldesleukin

  aldesleukin increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• amifostine

  amifostine, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.
  
  amifostine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.

• amiloride

  amiloride increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
  
  olmesartan and amiloride both increase serum potassium. Modify Therapy/Monitor Closely.

• amiodarone

  amiodarone will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• apalutamide

  apalutamide will decrease the level or effect of olmesartan by increasing elimination. Use Caution/Monitor. Apalutamide weakly induces OATP1B1 and may decrease systemic exposure of drugs that are OATP1B1 substrates.

• amoxicillin

  amoxicillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• arformoterol

  arformoterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• aspirin

  aspirin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• aspirin rectal

  aspirin rectal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  olmesartan and aspirin rectal both increase serum potassium. Use Caution/Monitor.

• aspirin/citric acid/sodium bicarbonate

  olmesartan, aspirin/citric acid/sodium bicarbonate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and aspirin/citric acid/sodium bicarbonate both increase serum potassium. Use Caution/Monitor.
  
  aspirin/citric acid/sodium bicarbonate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  aspirin/citric acid/sodium bicarbonate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• atenolol

  atenolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  atenolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and atenolol both increase serum potassium. Use Caution/Monitor.

• avanafil

  avanafil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
  
  avanafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• beclomethasone, inhaled

  beclomethasone, inhaled increases toxicity of hydrochlorothiazide by increasing elimination. Use Caution/Monitor. May increase the hypokalemic effects of thiazide diuretics.

• bendroflumethiazide

  olmesartan increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• benazepril

  benazepril increases toxicity of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects; increased risk of nephrotoxicity.

• bendroflumethiazide

  bendroflumethiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• betaxolol

  betaxolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and betaxolol both increase serum potassium. Use Caution/Monitor.
  
  betaxolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• bisoprolol

  olmesartan and bisoprolol both increase serum potassium. Use Caution/Monitor.
  
  bisoprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  bisoprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• bretylium

  hydrochlorothiazide, bretylium. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Each drug may cause hypotension.
  
  olmesartan, bretylium. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Each drug may cause hypotension.

• brimonidine

  brimonidine increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.

• bumetanide

  bumetanide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• bumetanide

  olmesartan increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• buprenorphine, long-acting injection

  buprenorphine, long-acting injection decreases effects of hydrochlorothiazide by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Opioids can reduce diuretic efficacy by inducing antidiuretic hormone release.

• calcifediol

  hydrochlorothiazide increases toxicity of calcifediol by Other (see comment). Use Caution/Monitor. Comment: Thiazide diuretics may increase serum calcium by decreasing urinary calcium excretion.

• canagliflozin

  olmesartan and canagliflozin both increase serum potassium. Use Caution/Monitor.

• candesartan

  candesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• captopril

  captopril, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure. Increased risk of nephrotoxicity. Monitor blood pressure and renal function.

• carbenoxolone

  hydrochlorothiazide and carbenoxolone both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• carbidopa

  carbidopa increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.

• carvedilol

  olmesartan and carvedilol both increase serum potassium. Use Caution/Monitor.
  
  carvedilol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• carvedilol

  carvedilol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• cefprozil

  hydrochlorothiazide will increase the level or effect of cefprozil by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• celecoxib

  celecoxib decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  celecoxib increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan, celecoxib. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and celecoxib both increase serum potassium. Use Caution/Monitor.

• celiprolol

  celiprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and celiprolol both increase serum potassium. Use Caution/Monitor.
  
  celiprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  hydrochlorothiazide decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• chlorothiazide

  olmesartan increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorothiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• chlorthalidone

  olmesartan increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorthalidone and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• cholestyramine

  cholestyramine decreases levels of hydrochlorothiazide by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• choline magnesium trisalicylate

  olmesartan and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.
  
  choline magnesium trisalicylate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, choline magnesium trisalicylate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• citalopram

  hydrochlorothiazide, citalopram. pharmacodynamic synergism. Use Caution/Monitor. Possible additive hyponatremia.

• colesevelam

  colesevelam decreases levels of olmesartan by drug binding in GI tract. Use Caution/Monitor. Concomitant administration decreases levothyroxine absorption; however, absorption is not reduced when levothyroxine is administered 4 hr before colesevelam.

• cornsilk

  cornsilk increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).

• corticotropin

  corticotropin increases toxicity of hydrochlorothiazide by increasing renal clearance. Use Caution/Monitor. May enhance hypokalemic effect of thiazide diuretics.

• cyclopenthiazide

  cyclopenthiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• cyclosporine

  cyclosporine increases toxicity of hydrochlorothiazide by unspecified interaction mechanism. Use Caution/Monitor. Coadministration of hydrochlorothiazide with cyclosporine may increase the risk of hypermagnesemia, hyperuricemia, and possible nephrotoxicity.

• dalteparin

  dalteparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• deflazacort

  hydrochlorothiazide and deflazacort both decrease serum potassium. Use Caution/Monitor.

• diazoxide

  hydrochlorothiazide increases toxicity of diazoxide by unspecified interaction mechanism. Use Caution/Monitor. May enhance hyperglycemic effects of diazoxide.

• dichlorphenamide

  dichlorphenamide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  olmesartan and diclofenac both increase serum potassium. Use Caution/Monitor.
  
  diclofenac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  diclofenac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, diclofenac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• dicloxacillin

  dicloxacillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• diflunisal

  olmesartan and diflunisal both increase serum potassium. Use Caution/Monitor.
  
  diflunisal decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, diflunisal. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• diflunisal

  diflunisal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• digoxin

  hydrochlorothiazide increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Hypokalemia increases digoxin effects.
  
  digoxin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  digoxin will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.
  
  olmesartan and digoxin both increase serum potassium. Use Caution/Monitor.

• dobutamine

  dobutamine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• dopexamine

  olmesartan increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dofetilide

  dofetilide will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• dopexamine

  dopexamine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• drospirenone

  olmesartan and drospirenone both increase serum potassium. Modify Therapy/Monitor Closely.
  
  drospirenone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• empagliflozin

  empagliflozin, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of empagliflozin with diuretics results in increased urine volume and frequency of voids, which might enhance the potential for volume depletion.

• enoxaparin

  enoxaparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• ephedrine

  ephedrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• epinephrine

  epinephrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• epinephrine racemic

  epinephrine racemic and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• eplerenone

  olmesartan, eplerenone. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of hyperkalemia.

• eprosartan

  eprosartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• esmolol

  esmolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and esmolol both increase serum potassium. Use Caution/Monitor.
  
  esmolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ethacrynic acid

  ethacrynic acid and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• etodolac

  olmesartan and etodolac both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, etodolac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  etodolac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  etodolac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• exenatide injectable solution

  olmesartan increases effects of exenatide injectable solution by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.
  
  hydrochlorothiazide decreases effects of exenatide injectable solution by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.

• exenatide injectable suspension

  olmesartan increases effects of exenatide injectable suspension by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.
  
  hydrochlorothiazide decreases effects of exenatide injectable suspension by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.

• fenbufen

  olmesartan and fenbufen both increase serum potassium. Use Caution/Monitor.

• fenoprofen

  fenoprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fenoprofen

  olmesartan and fenoprofen both increase serum potassium. Use Caution/Monitor.
  
  fenoprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, fenoprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• fentanyl

  fentanyl decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl intranasal

  fentanyl intranasal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl transdermal

  fentanyl transdermal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl transmucosal

  fentanyl transmucosal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• flurbiprofen

  olmesartan and flurbiprofen both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, flurbiprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  flurbiprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  flurbiprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• formoterol

  formoterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• fostemsavir

  fostemsavir will increase the level or effect of olmesartan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

• furosemide

  furosemide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• gentamicin

  hydrochlorothiazide and gentamicin both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• glecaprevir/pibrentasvir

  glecaprevir/pibrentasvir will increase the level or effect of olmesartan by Other (see comment). Use Caution/Monitor. Coadministration with glecaprevir/pibrentasvir may increase plasma concentration of drugs that are substrates of OATP1B1 or OATP1B3

• ibuprofen

  ibuprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• heparin

  heparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• hydrochlorothiazide

  olmesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ibuprofen

  olmesartan and ibuprofen both increase serum potassium. Use Caution/Monitor.
  
  ibuprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, ibuprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• ibuprofen IV

  olmesartan and ibuprofen IV both increase serum potassium. Use Caution/Monitor.
  
  hydrochlorothiazide will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.
  
  ibuprofen IV decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, ibuprofen IV. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ibuprofen IV increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. NSAIDs may decrease the therapeutic effects of thiazide-like diuretics; may also enhance nephrotoxic effects.

• indacaterol, inhaled

  hydrochlorothiazide, indacaterol, inhaled. serum potassium. Use Caution/Monitor. Combination may increase risk of hypokalemia.
  
  indacaterol, inhaled, hydrochlorothiazide. Other (see comment). Use Caution/Monitor. Comment: Caution is advised in the coadministration of indacaterol neohaler with non-potassium-sparing diuretics.

• indapamide

  olmesartan increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• indapamide

  hydrochlorothiazide and indapamide both decrease serum potassium. Use Caution/Monitor.

• indomethacin

  olmesartan, indomethacin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and indomethacin both increase serum potassium. Use Caution/Monitor.
  
  indomethacin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  indomethacin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• insulin aspart

  olmesartan increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  hydrochlorothiazide decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.

• insulin aspart protamine/insulin aspart

  olmesartan increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  olmesartan, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  olmesartan increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec/insulin aspart

  olmesartan, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  hydrochlorothiazide decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.

• insulin detemir

  olmesartan increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  hydrochlorothiazide decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.

• insulin glargine

  olmesartan increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin glulisine

  olmesartan increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin inhaled

  olmesartan, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  olmesartan increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin isophane human/insulin regular human

  olmesartan increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro

  olmesartan increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro protamine/insulin lispro

  olmesartan increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  olmesartan increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  olmesartan increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• irbesartan

  irbesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• isoproterenol

  isoproterenol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• juniper

  juniper, hydrochlorothiazide. Other (see comment). Use Caution/Monitor. Comment: Juniper may potentiate or interfere with diuretic therapy. Juniper has diuretic effects, but may cause kidney damage at large doses.

• ketoprofen

  olmesartan, ketoprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and ketoprofen both increase serum potassium. Use Caution/Monitor.
  
  ketoprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketoprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• ketorolac

  olmesartan, ketorolac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ketorolac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and ketorolac both increase serum potassium. Use Caution/Monitor.
  
  ketorolac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ketorolac intranasal

  olmesartan and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.
  
  ketorolac intranasal decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, ketorolac intranasal. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ketorolac intranasal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• labetalol

  labetalol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  labetalol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and labetalol both increase serum potassium. Use Caution/Monitor.

• letermovir

  letermovir increases levels of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Letermovir, an OATP1B1/3 inhibitor may increase plasma concentrations of coadministered OATP1B1/3 substrates.

• levalbuterol

  levalbuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• levodopa

  levodopa increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
  
  levodopa increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.

• lily of the valley

  hydrochlorothiazide increases toxicity of lily of the valley by Other (see comment). Use Caution/Monitor. Comment: Increased risk of cardiac toxicity due to K+ depletion.

• liraglutide

  olmesartan increases effects of liraglutide by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.

• liraglutide

  hydrochlorothiazide decreases effects of liraglutide by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.

• lithium

  hydrochlorothiazide increases toxicity of lithium by decreasing elimination. Use Caution/Monitor.

• lornoxicam

  lornoxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and lornoxicam both increase serum potassium. Use Caution/Monitor.

• losartan

  losartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lurasidone

  lurasidone increases effects of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.

• lurasidone

  lurasidone increases effects of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.

• maitake

  maitake increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.
  
  maitake increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).

• maraviroc

  maraviroc, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.

• meclofenamate

  meclofenamate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• meclofenamate

  meclofenamate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and meclofenamate both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, meclofenamate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• mefenamic acid

  olmesartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
  
  mefenamic acid increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  mefenamic acid decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• meloxicam

  meloxicam decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and meloxicam both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, meloxicam. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  meloxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaproterenol

  metaproterenol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• methyclothiazide

  olmesartan increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• methoxsalen

  methoxsalen, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methylphenidate

  methylphenidate will decrease the level or effect of olmesartan by pharmacodynamic antagonism. Use Caution/Monitor. Methylphenidate may diminish antihypertensive effects. Monitor BP.

• metolazone

  olmesartan increases and metolazone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  hydrochlorothiazide and metolazone both decrease serum potassium. Use Caution/Monitor.

• metoprolol

  hydrochlorothiazide, metoprolol. Either increases toxicity of the other by Other (see comment). Modify Therapy/Monitor Closely. Comment: May cause idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma, which can lead to permanent vision loss.
  
  metoprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  metoprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and metoprolol both increase serum potassium. Use Caution/Monitor.

• mometasone inhaled

  mometasone inhaled increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Corticosteroids may increase hypokalemic effect of loop diuretics.

• nabumetone

  olmesartan and nabumetone both increase serum potassium. Use Caution/Monitor.
  
  nabumetone decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, nabumetone. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• mycophenolate

  hydrochlorothiazide will increase the level or effect of mycophenolate by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• nabumetone

  nabumetone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nadolol

  nadolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nadolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and nadolol both increase serum potassium. Use Caution/Monitor.

• nafcillin

  nafcillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• naproxen

  olmesartan and naproxen both increase serum potassium. Use Caution/Monitor.
  
  naproxen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, naproxen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• naproxen

  naproxen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nebivolol

  olmesartan and nebivolol both increase serum potassium. Use Caution/Monitor.
  
  nebivolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nebivolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• nitroglycerin rectal

  nitroglycerin rectal, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Observe for possible additive hypotensive effects during concomitant use. .
  
  nitroglycerin rectal, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Observe for possible additive hypotensive effects during concomitant use. .

• norepinephrine

  norepinephrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• oxaprozin

  olmesartan and oxaprozin both increase serum potassium. Use Caution/Monitor.
  
  oxaprozin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, oxaprozin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• oliceridine

  oliceridine decreases effects of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Monitor for signs of diminished diuresis and/or effects on blood pressure and increase dosage of the diuretic as needed. .

• olmesartan

  olmesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• olodaterol inhaled

  hydrochlorothiazide and olodaterol inhaled both decrease serum potassium. Use Caution/Monitor.

• oxaprozin

  oxaprozin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• parecoxib

  parecoxib increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and parecoxib both increase serum potassium. Use Caution/Monitor.

• penbutolol

  olmesartan and penbutolol both increase serum potassium. Use Caution/Monitor.
  
  penbutolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  penbutolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• penicillin G aqueous

  penicillin G aqueous, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• pindolol

  olmesartan and pindolol both increase serum potassium. Use Caution/Monitor.
  
  pindolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• pindolol

  pindolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• pirbuterol

  pirbuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• piroxicam

  olmesartan and piroxicam both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, piroxicam. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  piroxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  piroxicam decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• pivmecillinam

  pivmecillinam, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• potassium acid phosphate

  olmesartan and potassium acid phosphate both increase serum potassium. Use Caution/Monitor.

• porfimer

  hydrochlorothiazide, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• potassium acid phosphate

  potassium acid phosphate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• potassium chloride

  olmesartan and potassium chloride both increase serum potassium. Use Caution/Monitor.
  
  potassium chloride increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• potassium citrate

  potassium citrate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
  
  olmesartan and potassium citrate both increase serum potassium. Use Caution/Monitor.

• potassium citrate/citric acid

  olmesartan and potassium citrate/citric acid both increase serum potassium. Modify Therapy/Monitor Closely.

• probenecid

  hydrochlorothiazide will increase the level or effect of probenecid by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• potassium iodide

  potassium iodide and olmesartan both increase serum potassium. Use Caution/Monitor. Potassium salts may increase the hyperkalemic effects of ARBs; the effect may be the result of aldosterone suppression in patients receiving ARBs.

• procainamide

  hydrochlorothiazide will increase the level or effect of procainamide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• propranolol

  propranolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and propranolol both increase serum potassium. Use Caution/Monitor.
  
  propranolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• quinidine

  quinidine will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• sacubitril/valsartan

  olmesartan and sacubitril/valsartan both increase serum potassium. Use Caution/Monitor.

• sacubitril/valsartan

  sacubitril/valsartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salicylates (non-asa)

  olmesartan and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.
  
  salicylates (non-asa) increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salmeterol

  salmeterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• salsalate

  olmesartan and salsalate both increase serum potassium. Use Caution/Monitor.
  
  salsalate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, salsalate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• salsalate

  salsalate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• shark cartilage

  hydrochlorothiazide, shark cartilage. Other (see comment). Use Caution/Monitor. Comment: May lead to hypercalcemia (theoretical).

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol

  hydrochlorothiazide and sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol both decrease serum potassium. Modify Therapy/Monitor Closely.

• sofosbuvir/velpatasvir

  sofosbuvir/velpatasvir increases levels of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Velpatasvir inhibits OATP1B1, OATP1B3, and OATP2B1 transporters. .

• sotalol

  sotalol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and sotalol both increase serum potassium. Use Caution/Monitor.
  
  sotalol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• spironolactone

  olmesartan and spironolactone both increase serum potassium. Modify Therapy/Monitor Closely.
  
  spironolactone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• succinylcholine

  succinylcholine increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• sulfasalazine

  olmesartan and sulfasalazine both increase serum potassium. Use Caution/Monitor.
  
  sulfasalazine decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, sulfasalazine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• sulfasalazine

  sulfasalazine increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• sulindac

  olmesartan, sulindac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  sulindac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and sulindac both increase serum potassium. Use Caution/Monitor.
  
  sulindac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• synthetic human angiotensin II

  olmesartan decreases effects of synthetic human angiotensin II by pharmacodynamic antagonism. Use Caution/Monitor.

• tadalafil

  tadalafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• tadalafil

  tadalafil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• telmisartan

  telmisartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• temocillin

  temocillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• terbutaline

  olmesartan increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  terbutaline and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• ticarcillin

  ticarcillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• timolol

  olmesartan and timolol both increase serum potassium. Use Caution/Monitor.
  
  timolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• timolol

  timolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tizanidine

  tizanidine increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• tolfenamic acid

  olmesartan and tolfenamic acid both increase serum potassium. Use Caution/Monitor.
  
  tolfenamic acid increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tolmetin

  olmesartan and tolmetin both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, tolmetin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  tolmetin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  tolmetin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• tolvaptan

  olmesartan and tolvaptan both increase serum potassium. Use Caution/Monitor.
  
  tolvaptan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• toremifene

  hydrochlorothiazide, toremifene. Other (see comment). Use Caution/Monitor. Comment: Thiazide diuretics decrease renal calcium excretion and may increase risk of hypercalcemia in patients taking toremifene.

• torsemide

  olmesartan increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• torsemide

  torsemide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• treprostinil

  treprostinil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.

• triamterene

  olmesartan and triamterene both increase serum potassium. Modify Therapy/Monitor Closely.
  
  triamterene increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• trientine

  hydrochlorothiazide decreases levels of trientine by increasing renal clearance. Use Caution/Monitor.

• trimethoprim

  trimethoprim and olmesartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.

• umeclidinium bromide/vilanterol inhaled

  umeclidinium bromide/vilanterol inhaled and hydrochlorothiazide both decrease serum potassium. Modify Therapy/Monitor Closely. Electrocardiographic changes and/or hypokalemia associated with non?potassium-sparing diuretics may worsen with concomitant beta-agonists, particularly if recommended dose is exceeded

• valsartan

  valsartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  vilanterol/fluticasone furoate inhaled and hydrochlorothiazide both decrease serum potassium. Modify Therapy/Monitor Closely. Beta-agonists may acutely worsen ECG changes and/or hypokalemia resulting from non-potassium-sparing diuretics

• vitamin D

  hydrochlorothiazide increases effects of vitamin D by Other (see comment). Use Caution/Monitor. Comment: Combination may increase hypercalcemic effect of vitamin D analogs. Use with caution.

• voclosporin

  voclosporin and olmesartan both increase serum potassium. Use Caution/Monitor.
  
  voclosporin, olmesartan. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

• xipamide

  xipamide increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor.
  
  xipamide increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.

Minor (154)

• acarbose

  hydrochlorothiazide decreases effects of acarbose by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• aceclofenac

  hydrochlorothiazide will increase the level or effect of aceclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acemetacin

  hydrochlorothiazide will increase the level or effect of acemetacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acyclovir

  hydrochlorothiazide will increase the level or effect of acyclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• agrimony

  agrimony increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.
  
  agrimony increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• albuterol

  albuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• cornsilk

  cornsilk increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• aminohippurate sodium

  hydrochlorothiazide will increase the level or effect of aminohippurate sodium by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ampicillin

  hydrochlorothiazide increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

• arformoterol

  arformoterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• aspirin

  hydrochlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aspirin rectal

  hydrochlorothiazide will increase the level or effect of aspirin rectal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  hydrochlorothiazide will increase the level or effect of aspirin/citric acid/sodium bicarbonate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• balsalazide

  hydrochlorothiazide will increase the level or effect of balsalazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• bendroflumethiazide

  bendroflumethiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• birch

  birch increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• bitter melon

  bitter melon, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• brimonidine

  brimonidine increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• budesonide

  budesonide, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• calcitriol topical

  calcitriol topical, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Potential additive hypercalcemia.

• calcium acetate

  hydrochlorothiazide increases levels of calcium acetate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium carbonate

  hydrochlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium chloride

  hydrochlorothiazide increases levels of calcium chloride by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium citrate

  hydrochlorothiazide increases levels of calcium citrate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium gluconate

  hydrochlorothiazide increases levels of calcium gluconate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• carbenoxolone

  hydrochlorothiazide, carbenoxolone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive hypokalemic effects.

• cefadroxil

  cefadroxil will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefamandole

  cefamandole will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefpirome

  cefpirome will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefprozil

  cefprozil will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftibuten

  ceftibuten will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celecoxib

  hydrochlorothiazide will increase the level or effect of celecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cephalexin

  cephalexin will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorothiazide

  chlorothiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorpropamide

  hydrochlorothiazide will increase the level or effect of chlorpropamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide decreases effects of chlorpropamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• chlorthalidone

  chlorthalidone will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• colestipol

  colestipol decreases levels of hydrochlorothiazide by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• cortisone

  cortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• cosyntropin

  cosyntropin, hydrochlorothiazide. pharmacodynamic synergism. Minor/Significance Unknown. Possible enhanced electrolyte loss.

• cyclopenthiazide

  cyclopenthiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• deflazacort

  deflazacort, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• dexamethasone

  dexamethasone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• diazoxide

  diazoxide, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperglycemia.

• diclofenac

  hydrochlorothiazide will increase the level or effect of diclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• diflunisal

  hydrochlorothiazide will increase the level or effect of diflunisal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• dobutamine

  dobutamine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• dopexamine

  dopexamine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• entecavir

  olmesartan, entecavir. Either increases effects of the other by decreasing renal clearance. Minor/Significance Unknown. Coadministration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the coadministered drug.

• ephedrine

  ephedrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine

  epinephrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine racemic

  epinephrine racemic, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epoprostenol

  epoprostenol increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.

• etodolac

  hydrochlorothiazide will increase the level or effect of etodolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fenbufen

  hydrochlorothiazide will increase the level or effect of fenbufen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fenoprofen

  hydrochlorothiazide will increase the level or effect of fenoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fludrocortisone

  fludrocortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• flurbiprofen

  hydrochlorothiazide will increase the level or effect of flurbiprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fo-ti

  fo-ti increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia (theoretical).

• folic acid

  hydrochlorothiazide decreases levels of folic acid by increasing renal clearance. Minor/Significance Unknown.

• formoterol

  formoterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• forskolin

  forskolin increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• ganciclovir

  hydrochlorothiazide will increase the level or effect of ganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• glimepiride

  hydrochlorothiazide decreases effects of glimepiride by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• glipizide

  hydrochlorothiazide decreases effects of glipizide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• glyburide

  hydrochlorothiazide decreases effects of glyburide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• goldenrod

  goldenrod increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• hydrocortisone

  hydrocortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• ibuprofen

  hydrochlorothiazide will increase the level or effect of ibuprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• indapamide

  hydrochlorothiazide will increase the level or effect of indapamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• indomethacin

  hydrochlorothiazide will increase the level or effect of indomethacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• insulin aspart

  hydrochlorothiazide decreases effects of insulin aspart by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin detemir

  hydrochlorothiazide decreases effects of insulin detemir by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin glargine

  hydrochlorothiazide decreases effects of insulin glargine by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin glulisine

  hydrochlorothiazide decreases effects of insulin glulisine by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin lispro

  hydrochlorothiazide decreases effects of insulin lispro by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin NPH

  hydrochlorothiazide decreases effects of insulin NPH by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin regular human

  hydrochlorothiazide decreases effects of insulin regular human by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• isoproterenol

  isoproterenol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• ketoprofen

  hydrochlorothiazide will increase the level or effect of ketoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac

  hydrochlorothiazide will increase the level or effect of ketorolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac intranasal

  hydrochlorothiazide will increase the level or effect of ketorolac intranasal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• L-methylfolate

  hydrochlorothiazide decreases levels of L-methylfolate by increasing renal clearance. Minor/Significance Unknown.

• levalbuterol

  levalbuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• lornoxicam

  hydrochlorothiazide will increase the level or effect of lornoxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• magnesium chloride

  hydrochlorothiazide decreases levels of magnesium chloride by increasing renal clearance. Minor/Significance Unknown.

• magnesium citrate

  hydrochlorothiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

• magnesium hydroxide

  hydrochlorothiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.

• magnesium oxide

  hydrochlorothiazide decreases levels of magnesium oxide by increasing renal clearance. Minor/Significance Unknown.

• magnesium sulfate

  hydrochlorothiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

• meclofenamate

  hydrochlorothiazide will increase the level or effect of meclofenamate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefenamic acid

  hydrochlorothiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• meloxicam

  hydrochlorothiazide will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• memantine

  hydrochlorothiazide will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mesalamine

  hydrochlorothiazide will increase the level or effect of mesalamine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• metaproterenol

  metaproterenol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• metformin

  hydrochlorothiazide will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide decreases effects of metformin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• methotrexate

  hydrochlorothiazide increases toxicity of methotrexate by decreasing elimination. Minor/Significance Unknown. Increased myelosuppression.

• methylprednisolone

  methylprednisolone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• metolazone

  hydrochlorothiazide will increase the level or effect of metolazone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• midodrine

  hydrochlorothiazide will increase the level or effect of midodrine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• miglitol

  hydrochlorothiazide decreases effects of miglitol by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• minoxidil

  hydrochlorothiazide increases effects of minoxidil by pharmacodynamic synergism. Minor/Significance Unknown.

• nabumetone

  hydrochlorothiazide will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• naproxen

  hydrochlorothiazide will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nateglinide

  hydrochlorothiazide decreases effects of nateglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• noni juice

  noni juice increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
  
  olmesartan and noni juice both increase serum potassium. Minor/Significance Unknown.

• norepinephrine

  norepinephrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.
  
  hydrochlorothiazide decreases effects of norepinephrine by pharmacodynamic antagonism. Minor/Significance Unknown. May decrease responsiveness to norepinephrine but not enough to preclude effectiveness of the pressor agent therapeutic use.

• octacosanol

  octacosanol increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• octacosanol

  octacosanol increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• ofloxacin

  hydrochlorothiazide will increase the level or effect of ofloxacin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• oxaprozin

  hydrochlorothiazide will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• parecoxib

  hydrochlorothiazide will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• penicillin G aqueous

  hydrochlorothiazide increases levels of penicillin G aqueous by decreasing renal clearance. Minor/Significance Unknown.

• penicillin VK

  hydrochlorothiazide increases levels of penicillin VK by decreasing renal clearance. Minor/Significance Unknown.

• pioglitazone

  hydrochlorothiazide decreases effects of pioglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• piperacillin

  hydrochlorothiazide increases levels of piperacillin by decreasing renal clearance. Minor/Significance Unknown.

• pirbuterol

  pirbuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• piroxicam

  hydrochlorothiazide will increase the level or effect of piroxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• prednisolone

  prednisolone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• prednisone

  prednisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• quinine

  hydrochlorothiazide will increase the level or effect of quinine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• reishi

  reishi increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.
  
  reishi increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• repaglinide

  hydrochlorothiazide decreases effects of repaglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• shepherd's purse

  shepherd's purse, olmesartan. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.

• rose hips

  rose hips will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• rosiglitazone

  hydrochlorothiazide decreases effects of rosiglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• salicylates (non-asa)

  hydrochlorothiazide will increase the level or effect of salicylates (non-asa) by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• salmeterol

  salmeterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• salsalate

  hydrochlorothiazide will increase the level or effect of salsalate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• saxagliptin

  hydrochlorothiazide decreases effects of saxagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• shepherd's purse

  shepherd's purse, hydrochlorothiazide. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.

• sitagliptin

  hydrochlorothiazide decreases effects of sitagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• sulfadiazine

  hydrochlorothiazide increases levels of sulfadiazine by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfamethoxazole

  sulfamethoxazole will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide increases levels of sulfamethoxazole by unspecified interaction mechanism. Minor/Significance Unknown.
  
  hydrochlorothiazide, sulfamethoxazole. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• sulfasalazine

  hydrochlorothiazide will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• sulfisoxazole

  hydrochlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sulindac

  hydrochlorothiazide will increase the level or effect of sulindac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• terbutaline

  terbutaline, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.
  
  hydrochlorothiazide, terbutaline. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive hypokalemic effects.

• tizanidine

  tizanidine increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.

• tolazamide

  hydrochlorothiazide decreases effects of tolazamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• tolbutamide

  hydrochlorothiazide decreases effects of tolbutamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• tolfenamic acid

  hydrochlorothiazide will increase the level or effect of tolfenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolmetin

  hydrochlorothiazide will increase the level or effect of tolmetin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• treprostinil

  treprostinil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• triamcinolone acetonide injectable suspension

  triamcinolone acetonide injectable suspension, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• triamterene

  hydrochlorothiazide will increase the level or effect of triamterene by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• trilostane

  trilostane, hydrochlorothiazide. Other (see comment). Minor/Significance Unknown. Comment: Trilostane reduces K+ loss while maintaining the natriuretic effect. Mechanism: inhibition of mineralocorticoid steroid synthesis.

• trimethoprim

  hydrochlorothiazide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• valganciclovir

  hydrochlorothiazide will increase the level or effect of valganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• verapamil

  hydrochlorothiazide will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• verteporfin

  hydrochlorothiazide, verteporfin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased phototoxicity.

• vildagliptin

  hydrochlorothiazide decreases effects of vildagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• voclosporin

  voclosporin will increase the level or effect of olmesartan by Other (see comment). Minor/Significance Unknown. Information suggests voclosporin (an OATP1B1 inhibitor) may increase in the concentration of OATP1B1 substrates is possible. Monitor for adverse reactions of OATP1B1 substrates when coadministered with voclosporin.

• willow bark

  hydrochlorothiazide will increase the level or effect of willow bark by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acarbose

  Minor (1)hydrochlorothiazide decreases effects of acarbose by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• acebutolol

  Monitor Closely (3)acebutolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  acebutolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and acebutolol both increase serum potassium. Use Caution/Monitor.

• aceclofenac

  Monitor Closely (2)olmesartan and aceclofenac both increase serum potassium. Use Caution/Monitor.
  
  aceclofenac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of aceclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acemetacin

  Monitor Closely (2)olmesartan and acemetacin both increase serum potassium. Use Caution/Monitor.
  
  acemetacin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of acemetacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acyclovir

  Minor (1)hydrochlorothiazide will increase the level or effect of acyclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• agrimony

  Minor (2)agrimony increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.
  
  agrimony increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• albiglutide

  Monitor Closely (2)hydrochlorothiazide decreases effects of albiglutide by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.
  
  olmesartan increases effects of albiglutide by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.

• albuterol

  Monitor Closely (1)albuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)albuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• aldesleukin

  Monitor Closely (2)aldesleukin increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
  
  aldesleukin increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• aliskiren

  Contraindicated (1)olmesartan decreases effects of aliskiren by Other (see comment). Contraindicated. Comment: Aliskiren use contraindicated with ARBs in patients with diabetes; avoid coadministration with ARBs if GFR. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of ARBS with drugs that affect RAAS may increase the risk of renal impairment (including acute renal failure) and cause loss of antihypertensive effect. Monitor renal function periodically.

• amifostine

  Monitor Closely (2)amifostine, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.
  
  amifostine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.

• amiloride

  Monitor Closely (2)amiloride increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
  
  olmesartan and amiloride both increase serum potassium. Modify Therapy/Monitor Closely.

• aminohippurate sodium

  Minor (1)hydrochlorothiazide will increase the level or effect of aminohippurate sodium by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aminolevulinic acid oral

  Serious - Use Alternative (1)aminolevulinic acid oral, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.

• aminolevulinic acid topical

  Serious - Use Alternative (1)hydrochlorothiazide increases toxicity of aminolevulinic acid topical by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of photosensitizing drugs may enhance the phototoxic reaction to photodynamic therapy with aminolevulinic acid.

• amiodarone

  Monitor Closely (1)amiodarone will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• amoxicillin

  Monitor Closely (1)amoxicillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ampicillin

  Minor (1)hydrochlorothiazide increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

• apalutamide

  Monitor Closely (1)apalutamide will decrease the level or effect of olmesartan by increasing elimination. Use Caution/Monitor. Apalutamide weakly induces OATP1B1 and may decrease systemic exposure of drugs that are OATP1B1 substrates.

• arformoterol

  Monitor Closely (1)arformoterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)arformoterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• aspirin

  Monitor Closely (4)aspirin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.Minor (1)hydrochlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aspirin rectal

  Monitor Closely (2)aspirin rectal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  olmesartan and aspirin rectal both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of aspirin rectal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aspirin/citric acid/sodium bicarbonate

  Monitor Closely (4)olmesartan, aspirin/citric acid/sodium bicarbonate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and aspirin/citric acid/sodium bicarbonate both increase serum potassium. Use Caution/Monitor.
  
  aspirin/citric acid/sodium bicarbonate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  aspirin/citric acid/sodium bicarbonate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of aspirin/citric acid/sodium bicarbonate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• atenolol

  Monitor Closely (3)atenolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  atenolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and atenolol both increase serum potassium. Use Caution/Monitor.

• avanafil

  Monitor Closely (2)avanafil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
  
  avanafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• balsalazide

  Minor (1)hydrochlorothiazide will increase the level or effect of balsalazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• beclomethasone, inhaled

  Monitor Closely (1)beclomethasone, inhaled increases toxicity of hydrochlorothiazide by increasing elimination. Use Caution/Monitor. May increase the hypokalemic effects of thiazide diuretics.

• benazepril

  Monitor Closely (1)benazepril increases toxicity of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects; increased risk of nephrotoxicity.Serious - Use Alternative (1)olmesartan, benazepril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• bendroflumethiazide

  Monitor Closely (2)olmesartan increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  bendroflumethiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)bendroflumethiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• betaxolol

  Monitor Closely (3)betaxolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and betaxolol both increase serum potassium. Use Caution/Monitor.
  
  betaxolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• birch

  Minor (1)birch increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• bisoprolol

  Monitor Closely (3)olmesartan and bisoprolol both increase serum potassium. Use Caution/Monitor.
  
  bisoprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  bisoprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• bitter melon

  Minor (1)bitter melon, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• bretylium

  Monitor Closely (2)hydrochlorothiazide, bretylium. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Each drug may cause hypotension.
  
  olmesartan, bretylium. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Each drug may cause hypotension.

• brimonidine

  Monitor Closely (1)brimonidine increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.Minor (1)brimonidine increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• budesonide

  Minor (1)budesonide, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• bumetanide

  Monitor Closely (2)bumetanide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• buprenorphine, long-acting injection

  Monitor Closely (1)buprenorphine, long-acting injection decreases effects of hydrochlorothiazide by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Opioids can reduce diuretic efficacy by inducing antidiuretic hormone release.

• calcifediol

  Monitor Closely (1)hydrochlorothiazide increases toxicity of calcifediol by Other (see comment). Use Caution/Monitor. Comment: Thiazide diuretics may increase serum calcium by decreasing urinary calcium excretion.

• calcitriol topical

  Minor (1)calcitriol topical, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Potential additive hypercalcemia.

• calcium acetate

  Minor (1)hydrochlorothiazide increases levels of calcium acetate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium carbonate

  Minor (1)hydrochlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium chloride

  Minor (1)hydrochlorothiazide increases levels of calcium chloride by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium citrate

  Minor (1)hydrochlorothiazide increases levels of calcium citrate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium gluconate

  Minor (1)hydrochlorothiazide increases levels of calcium gluconate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• canagliflozin

  Monitor Closely (1)olmesartan and canagliflozin both increase serum potassium. Use Caution/Monitor.

• candesartan

  Monitor Closely (1)candesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• captopril

  Monitor Closely (1)captopril, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure. Increased risk of nephrotoxicity. Monitor blood pressure and renal function.Serious - Use Alternative (1)olmesartan, captopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• carbamazepine

  Serious - Use Alternative (1)carbamazepine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of systemic hyponatremia.

• carbenoxolone

  Monitor Closely (2)hydrochlorothiazide and carbenoxolone both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide, carbenoxolone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive hypokalemic effects.

• carbidopa

  Monitor Closely (1)carbidopa increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.

• carvedilol

  Monitor Closely (3)carvedilol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and carvedilol both increase serum potassium. Use Caution/Monitor.
  
  carvedilol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• cefadroxil

  Minor (1)cefadroxil will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefamandole

  Minor (1)cefamandole will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefpirome

  Minor (1)cefpirome will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefprozil

  Monitor Closely (1)hydrochlorothiazide will increase the level or effect of cefprozil by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.Minor (1)cefprozil will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftibuten

  Minor (1)ceftibuten will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celecoxib

  Monitor Closely (4)celecoxib decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  celecoxib increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan, celecoxib. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and celecoxib both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of celecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celiprolol

  Monitor Closely (4)celiprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and celiprolol both increase serum potassium. Use Caution/Monitor.
  
  celiprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  hydrochlorothiazide decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• cephalexin

  Minor (1)cephalexin will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorothiazide

  Monitor Closely (2)olmesartan increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorothiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)chlorothiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorpropamide

  Minor (2)hydrochlorothiazide will increase the level or effect of chlorpropamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide decreases effects of chlorpropamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• chlorthalidone

  Monitor Closely (2)olmesartan increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorthalidone and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cholestyramine

  Monitor Closely (1)cholestyramine decreases levels of hydrochlorothiazide by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• choline magnesium trisalicylate

  Monitor Closely (3)olmesartan, choline magnesium trisalicylate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  choline magnesium trisalicylate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.

• citalopram

  Monitor Closely (1)hydrochlorothiazide, citalopram. pharmacodynamic synergism. Use Caution/Monitor. Possible additive hyponatremia.

• colesevelam

  Monitor Closely (1)colesevelam decreases levels of olmesartan by drug binding in GI tract. Use Caution/Monitor. Concomitant administration decreases levothyroxine absorption; however, absorption is not reduced when levothyroxine is administered 4 hr before colesevelam.

• colestipol

  Minor (1)colestipol decreases levels of hydrochlorothiazide by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• cornsilk

  Monitor Closely (1)cornsilk increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).Minor (1)cornsilk increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• corticotropin

  Monitor Closely (1)corticotropin increases toxicity of hydrochlorothiazide by increasing renal clearance. Use Caution/Monitor. May enhance hypokalemic effect of thiazide diuretics.

• cortisone

  Minor (1)cortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• cosyntropin

  Minor (1)cosyntropin, hydrochlorothiazide. pharmacodynamic synergism. Minor/Significance Unknown. Possible enhanced electrolyte loss.

• cyclopenthiazide

  Monitor Closely (2)cyclopenthiazide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)cyclopenthiazide will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cyclophosphamide

  Serious - Use Alternative (1)hydrochlorothiazide increases toxicity of cyclophosphamide by decreasing renal clearance. Avoid or Use Alternate Drug. Increased myelosuppressive effects.

• cyclosporine

  Monitor Closely (1)cyclosporine increases toxicity of hydrochlorothiazide by unspecified interaction mechanism. Use Caution/Monitor. Coadministration of hydrochlorothiazide with cyclosporine may increase the risk of hypermagnesemia, hyperuricemia, and possible nephrotoxicity.Serious - Use Alternative (1)cyclosporine, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of systemic hyponatremia.

• dalteparin

  Monitor Closely (1)dalteparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• deflazacort

  Monitor Closely (1)hydrochlorothiazide and deflazacort both decrease serum potassium. Use Caution/Monitor.Minor (1)deflazacort, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• dexamethasone

  Minor (1)dexamethasone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• diazoxide

  Monitor Closely (1)hydrochlorothiazide increases toxicity of diazoxide by unspecified interaction mechanism. Use Caution/Monitor. May enhance hyperglycemic effects of diazoxide.Minor (1)diazoxide, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperglycemia.

• dichlorphenamide

  Monitor Closely (1)dichlorphenamide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  Monitor Closely (4)olmesartan and diclofenac both increase serum potassium. Use Caution/Monitor.
  
  diclofenac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  diclofenac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, diclofenac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.Minor (1)hydrochlorothiazide will increase the level or effect of diclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• dicloxacillin

  Monitor Closely (1)dicloxacillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• diflunisal

  Monitor Closely (4)diflunisal decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and diflunisal both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, diflunisal. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  diflunisal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of diflunisal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• digoxin

  Monitor Closely (4)hydrochlorothiazide increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Hypokalemia increases digoxin effects.
  
  digoxin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and digoxin both increase serum potassium. Use Caution/Monitor.
  
  digoxin will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• dobutamine

  Monitor Closely (1)dobutamine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)dobutamine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• dofetilide

  Monitor Closely (1)dofetilide will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.Serious - Use Alternative (1)hydrochlorothiazide increases levels of dofetilide by decreasing renal clearance. Contraindicated. Risk of prolonged QTc interval.

• dopexamine

  Monitor Closely (2)dopexamine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)dopexamine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• drospirenone

  Monitor Closely (2)olmesartan and drospirenone both increase serum potassium. Modify Therapy/Monitor Closely.
  
  drospirenone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• empagliflozin

  Monitor Closely (1)empagliflozin, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of empagliflozin with diuretics results in increased urine volume and frequency of voids, which might enhance the potential for volume depletion.

• enalapril

  Serious - Use Alternative (1)olmesartan, enalapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• enoxaparin

  Monitor Closely (1)enoxaparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• entecavir

  Minor (1)olmesartan, entecavir. Either increases effects of the other by decreasing renal clearance. Minor/Significance Unknown. Coadministration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the coadministered drug.

• ephedrine

  Monitor Closely (1)ephedrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)ephedrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine

  Monitor Closely (1)epinephrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)epinephrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine racemic

  Monitor Closely (1)epinephrine racemic and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)epinephrine racemic, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• eplerenone

  Monitor Closely (1)olmesartan, eplerenone. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of hyperkalemia.

• epoprostenol

  Minor (1)epoprostenol increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.

• eprosartan

  Monitor Closely (1)eprosartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• esmolol

  Monitor Closely (3)esmolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and esmolol both increase serum potassium. Use Caution/Monitor.
  
  esmolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ethacrynic acid

  Monitor Closely (2)ethacrynic acid and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• etodolac

  Monitor Closely (4)olmesartan, etodolac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and etodolac both increase serum potassium. Use Caution/Monitor.
  
  etodolac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  etodolac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of etodolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• exenatide injectable solution

  Monitor Closely (2)olmesartan increases effects of exenatide injectable solution by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.
  
  hydrochlorothiazide decreases effects of exenatide injectable solution by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.

• exenatide injectable suspension

  Monitor Closely (2)olmesartan increases effects of exenatide injectable suspension by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.
  
  hydrochlorothiazide decreases effects of exenatide injectable suspension by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.

• fenbufen

  Monitor Closely (1)olmesartan and fenbufen both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of fenbufen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fenoprofen

  Monitor Closely (4)olmesartan, fenoprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  fenoprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  fenoprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and fenoprofen both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of fenoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fentanyl

  Monitor Closely (1)fentanyl decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl intranasal

  Monitor Closely (1)fentanyl intranasal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl transdermal

  Monitor Closely (1)fentanyl transdermal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fentanyl transmucosal

  Monitor Closely (1)fentanyl transmucosal decreases effects of hydrochlorothiazide by Other (see comment). Modify Therapy/Monitor Closely. Comment: Fentanyl can reduce the efficacy of diuretics by inducing antidiuretic hormone release. Fentanyl may also lead to acute urinary retention by causing bladder sphincter spasm (particularly in men with enlarged prostates).

• fludrocortisone

  Minor (1)fludrocortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• flurbiprofen

  Monitor Closely (4)olmesartan and flurbiprofen both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, flurbiprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  flurbiprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  flurbiprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of flurbiprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fo-ti

  Minor (1)fo-ti increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia (theoretical).

• folic acid

  Minor (1)hydrochlorothiazide decreases levels of folic acid by increasing renal clearance. Minor/Significance Unknown.

• formoterol

  Monitor Closely (1)formoterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)formoterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• forskolin

  Minor (1)forskolin increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• fosinopril

  Serious - Use Alternative (1)olmesartan, fosinopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• fostemsavir

  Monitor Closely (1)fostemsavir will increase the level or effect of olmesartan by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits OATP1B1/3 transporter. If possible, avoid coadministration or modify dose of OATP1B1/3 substrates coadministered with fostemsavir.

• furosemide

  Monitor Closely (2)furosemide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ganciclovir

  Minor (1)hydrochlorothiazide will increase the level or effect of ganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• gentamicin

  Monitor Closely (2)hydrochlorothiazide and gentamicin both decrease serum potassium. Use Caution/Monitor.
  
  olmesartan increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• glecaprevir/pibrentasvir

  Monitor Closely (1)glecaprevir/pibrentasvir will increase the level or effect of olmesartan by Other (see comment). Use Caution/Monitor. Coadministration with glecaprevir/pibrentasvir may increase plasma concentration of drugs that are substrates of OATP1B1 or OATP1B3

• glimepiride

  Minor (1)hydrochlorothiazide decreases effects of glimepiride by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• glipizide

  Minor (1)hydrochlorothiazide decreases effects of glipizide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• glyburide

  Minor (1)hydrochlorothiazide decreases effects of glyburide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• goldenrod

  Minor (1)goldenrod increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• heparin

  Monitor Closely (1)heparin increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Low molecular weight heparins may suppress adrenal aldosterone secretion, which can potentially cause hyperkalemia.

• hydrochlorothiazide

  Monitor Closely (1)olmesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• hydrocortisone

  Minor (1)hydrocortisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• ibuprofen

  Monitor Closely (4)olmesartan, ibuprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and ibuprofen both increase serum potassium. Use Caution/Monitor.
  
  ibuprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ibuprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of ibuprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ibuprofen IV

  Monitor Closely (5)olmesartan and ibuprofen IV both increase serum potassium. Use Caution/Monitor.
  
  ibuprofen IV decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  hydrochlorothiazide will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.
  
  olmesartan, ibuprofen IV. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ibuprofen IV increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. NSAIDs may decrease the therapeutic effects of thiazide-like diuretics; may also enhance nephrotoxic effects.

• indacaterol, inhaled

  Monitor Closely (2)hydrochlorothiazide, indacaterol, inhaled. serum potassium. Use Caution/Monitor. Combination may increase risk of hypokalemia.
  
  indacaterol, inhaled, hydrochlorothiazide. Other (see comment). Use Caution/Monitor. Comment: Caution is advised in the coadministration of indacaterol neohaler with non-potassium-sparing diuretics.

• indapamide

  Monitor Closely (2)olmesartan increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  hydrochlorothiazide and indapamide both decrease serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of indapamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• indomethacin

  Monitor Closely (4)olmesartan, indomethacin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and indomethacin both increase serum potassium. Use Caution/Monitor.
  
  indomethacin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  indomethacin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of indomethacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• insulin aspart

  Monitor Closely (1)olmesartan increases effects of insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin aspart by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin aspart protamine/insulin aspart

  Monitor Closely (1)olmesartan increases effects of insulin aspart protamine/insulin aspart by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin degludec

  Monitor Closely (3)hydrochlorothiazide decreases effects of insulin degludec by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.
  
  olmesartan increases effects of insulin degludec by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.
  
  olmesartan, insulin degludec. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin degludec/insulin aspart

  Monitor Closely (2)olmesartan, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  hydrochlorothiazide decreases effects of insulin degludec/insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.

• insulin detemir

  Monitor Closely (1)olmesartan increases effects of insulin detemir by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin detemir by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin glargine

  Monitor Closely (1)olmesartan increases effects of insulin glargine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin glargine by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin glulisine

  Monitor Closely (1)olmesartan increases effects of insulin glulisine by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin glulisine by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin inhaled

  Monitor Closely (3)olmesartan, insulin inhaled. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.
  
  olmesartan increases effects of insulin inhaled by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.
  
  hydrochlorothiazide decreases effects of insulin inhaled by Other (see comment). Use Caution/Monitor. Comment: Diuretics may cause hyperglycemia and glycosuria in patients with diabetes mellitus, possibly by diuretic-induced hpokalemia.

• insulin isophane human/insulin regular human

  Monitor Closely (1)olmesartan increases effects of insulin isophane human/insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin lispro

  Monitor Closely (1)olmesartan increases effects of insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin lispro by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• insulin lispro protamine/insulin lispro

  Monitor Closely (1)olmesartan increases effects of insulin lispro protamine/insulin lispro by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin NPH

  Monitor Closely (1)olmesartan increases effects of insulin NPH by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.

• insulin regular human

  Monitor Closely (1)olmesartan increases effects of insulin regular human by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use of insulin and ARBs may require insulin dosage adjustment and increased glucose monitoring.Minor (1)hydrochlorothiazide decreases effects of insulin regular human by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• irbesartan

  Monitor Closely (1)irbesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• isocarboxazid

  Serious - Use Alternative (1)isocarboxazid, hydrochlorothiazide. Other (see comment). Contraindicated. Comment: Additive hypotensive effects may be seen when MAOI's are combined with antihypertensives.

• isoproterenol

  Monitor Closely (1)isoproterenol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)isoproterenol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• juniper

  Monitor Closely (1)juniper, hydrochlorothiazide. Other (see comment). Use Caution/Monitor. Comment: Juniper may potentiate or interfere with diuretic therapy. Juniper has diuretic effects, but may cause kidney damage at large doses.

• ketoprofen

  Monitor Closely (4)olmesartan, ketoprofen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and ketoprofen both increase serum potassium. Use Caution/Monitor.
  
  ketoprofen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketoprofen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of ketoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac

  Monitor Closely (4)olmesartan, ketorolac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ketorolac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and ketorolac both increase serum potassium. Use Caution/Monitor.
  
  ketorolac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of ketorolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac intranasal

  Monitor Closely (4)olmesartan and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.
  
  ketorolac intranasal decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, ketorolac intranasal. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  ketorolac intranasal increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .Minor (1)hydrochlorothiazide will increase the level or effect of ketorolac intranasal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• L-methylfolate

  Minor (1)hydrochlorothiazide decreases levels of L-methylfolate by increasing renal clearance. Minor/Significance Unknown.

• labetalol

  Monitor Closely (3)labetalol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  labetalol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and labetalol both increase serum potassium. Use Caution/Monitor.

• letermovir

  Monitor Closely (1)letermovir increases levels of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Letermovir, an OATP1B1/3 inhibitor may increase plasma concentrations of coadministered OATP1B1/3 substrates.

• levalbuterol

  Monitor Closely (1)levalbuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)levalbuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• levodopa

  Monitor Closely (2)levodopa increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
  
  levodopa increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.

• lily of the valley

  Monitor Closely (1)hydrochlorothiazide increases toxicity of lily of the valley by Other (see comment). Use Caution/Monitor. Comment: Increased risk of cardiac toxicity due to K+ depletion.

• liraglutide

  Monitor Closely (2)hydrochlorothiazide decreases effects of liraglutide by pharmacodynamic antagonism. Use Caution/Monitor. Thiazide diuretics can decrease insulin sensitivity thereby leading to glucose intolerance and hyperglycemia. Monitor glycemic control especially when initiating, discontinuing, or increasing thiazide diuretic dose.
  
  olmesartan increases effects of liraglutide by Other (see comment). Use Caution/Monitor. Comment: Angiotensin II receptor antagonists may enhance hypoglycemic effects of antidiabetic agents by improving insulin sensitivity. Monitor patients for changes in glycemic control.

• lisinopril

  Serious - Use Alternative (1)olmesartan, lisinopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• lithium

  Monitor Closely (1)hydrochlorothiazide increases toxicity of lithium by decreasing elimination. Use Caution/Monitor.Serious - Use Alternative (1)olmesartan increases toxicity of lithium by decreasing renal clearance. Avoid or Use Alternate Drug.

• lofexidine

  Serious - Use Alternative (2)lofexidine, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that decrease pulse or blood pressure to mitigate risk of excessive bradycardia and hypotension.
  
  lofexidine, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that decrease pulse or blood pressure to mitigate risk of excessive bradycardia and hypotension.

• lornoxicam

  Monitor Closely (2)lornoxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and lornoxicam both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of lornoxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• losartan

  Monitor Closely (1)losartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lurasidone

  Monitor Closely (2)lurasidone increases effects of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.
  
  lurasidone increases effects of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.

• magnesium chloride

  Minor (1)hydrochlorothiazide decreases levels of magnesium chloride by increasing renal clearance. Minor/Significance Unknown.

• magnesium citrate

  Minor (1)hydrochlorothiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

• magnesium hydroxide

  Minor (1)hydrochlorothiazide decreases levels of magnesium hydroxide by increasing renal clearance. Minor/Significance Unknown.

• magnesium oxide

  Minor (1)hydrochlorothiazide decreases levels of magnesium oxide by increasing renal clearance. Minor/Significance Unknown.

• magnesium sulfate

  Minor (1)hydrochlorothiazide decreases levels of magnesium sulfate by increasing renal clearance. Minor/Significance Unknown.

• maitake

  Monitor Closely (2)maitake increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.
  
  maitake increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).

• maraviroc

  Monitor Closely (1)maraviroc, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.

• meclofenamate

  Monitor Closely (4)olmesartan, meclofenamate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and meclofenamate both increase serum potassium. Use Caution/Monitor.
  
  meclofenamate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  meclofenamate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of meclofenamate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefenamic acid

  Monitor Closely (4)olmesartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
  
  mefenamic acid increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  mefenamic acid decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.Minor (1)hydrochlorothiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• meloxicam

  Monitor Closely (4)meloxicam decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and meloxicam both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, meloxicam. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  meloxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• memantine

  Minor (1)hydrochlorothiazide will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mesalamine

  Minor (1)hydrochlorothiazide will increase the level or effect of mesalamine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• metaproterenol

  Monitor Closely (1)metaproterenol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)metaproterenol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• metformin

  Minor (2)hydrochlorothiazide will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide decreases effects of metformin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• methotrexate

  Minor (1)hydrochlorothiazide increases toxicity of methotrexate by decreasing elimination. Minor/Significance Unknown. Increased myelosuppression.

• methoxsalen

  Monitor Closely (1)methoxsalen, hydrochlorothiazide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

• methyclothiazide

  Monitor Closely (1)olmesartan increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• methyl aminolevulinate

  Serious - Use Alternative (1)hydrochlorothiazide, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.

• methylphenidate

  Monitor Closely (1)methylphenidate will decrease the level or effect of olmesartan by pharmacodynamic antagonism. Use Caution/Monitor. Methylphenidate may diminish antihypertensive effects. Monitor BP.

• methylprednisolone

  Minor (1)methylprednisolone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• metolazone

  Monitor Closely (2)olmesartan increases and metolazone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  hydrochlorothiazide and metolazone both decrease serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of metolazone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• metoprolol

  Monitor Closely (4)hydrochlorothiazide, metoprolol. Either increases toxicity of the other by Other (see comment). Modify Therapy/Monitor Closely. Comment: May cause idiosyncratic reaction, resulting in acute transient myopia and acute angle-closure glaucoma, which can lead to permanent vision loss.
  
  metoprolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  metoprolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and metoprolol both increase serum potassium. Use Caution/Monitor.

• midodrine

  Minor (1)hydrochlorothiazide will increase the level or effect of midodrine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• miglitol

  Minor (1)hydrochlorothiazide decreases effects of miglitol by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• minoxidil

  Minor (1)hydrochlorothiazide increases effects of minoxidil by pharmacodynamic synergism. Minor/Significance Unknown.

• moexipril

  Serious - Use Alternative (1)olmesartan, moexipril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• mometasone inhaled

  Monitor Closely (1)mometasone inhaled increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Corticosteroids may increase hypokalemic effect of loop diuretics.

• mycophenolate

  Monitor Closely (1)hydrochlorothiazide will increase the level or effect of mycophenolate by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• nabumetone

  Monitor Closely (4)nabumetone decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and nabumetone both increase serum potassium. Use Caution/Monitor.
  
  nabumetone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan, nabumetone. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.Minor (1)hydrochlorothiazide will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nadolol

  Monitor Closely (3)nadolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nadolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and nadolol both increase serum potassium. Use Caution/Monitor.

• nafcillin

  Monitor Closely (1)nafcillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• naproxen

  Monitor Closely (4)naproxen decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, naproxen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and naproxen both increase serum potassium. Use Caution/Monitor.
  
  naproxen increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nateglinide

  Minor (1)hydrochlorothiazide decreases effects of nateglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• nebivolol

  Monitor Closely (3)olmesartan and nebivolol both increase serum potassium. Use Caution/Monitor.
  
  nebivolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nebivolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• nitroglycerin rectal

  Monitor Closely (2)nitroglycerin rectal, hydrochlorothiazide. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Observe for possible additive hypotensive effects during concomitant use. .
  
  nitroglycerin rectal, olmesartan. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Observe for possible additive hypotensive effects during concomitant use. .

• noni juice

  Minor (2)noni juice increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
  
  olmesartan and noni juice both increase serum potassium. Minor/Significance Unknown.

• norepinephrine

  Monitor Closely (1)norepinephrine and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (2)norepinephrine, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.
  
  hydrochlorothiazide decreases effects of norepinephrine by pharmacodynamic antagonism. Minor/Significance Unknown. May decrease responsiveness to norepinephrine but not enough to preclude effectiveness of the pressor agent therapeutic use.

• octacosanol

  Minor (2)octacosanol increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.
  
  octacosanol increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• ofloxacin

  Minor (1)hydrochlorothiazide will increase the level or effect of ofloxacin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• oliceridine

  Monitor Closely (1)oliceridine decreases effects of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Monitor for signs of diminished diuresis and/or effects on blood pressure and increase dosage of the diuretic as needed. .

• olmesartan

  Monitor Closely (1)olmesartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• olodaterol inhaled

  Monitor Closely (1)hydrochlorothiazide and olodaterol inhaled both decrease serum potassium. Use Caution/Monitor.

• oxaprozin

  Monitor Closely (4)oxaprozin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  oxaprozin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and oxaprozin both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, oxaprozin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.Minor (1)hydrochlorothiazide will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• parecoxib

  Monitor Closely (2)parecoxib increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and parecoxib both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• penbutolol

  Monitor Closely (3)olmesartan and penbutolol both increase serum potassium. Use Caution/Monitor.
  
  penbutolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  penbutolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• penicillin G aqueous

  Monitor Closely (1)penicillin G aqueous, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.Minor (1)hydrochlorothiazide increases levels of penicillin G aqueous by decreasing renal clearance. Minor/Significance Unknown.

• penicillin VK

  Minor (1)hydrochlorothiazide increases levels of penicillin VK by decreasing renal clearance. Minor/Significance Unknown.

• perindopril

  Serious - Use Alternative (1)olmesartan, perindopril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• pindolol

  Monitor Closely (3)olmesartan and pindolol both increase serum potassium. Use Caution/Monitor.
  
  pindolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  pindolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.

• pioglitazone

  Minor (1)hydrochlorothiazide decreases effects of pioglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• piperacillin

  Minor (1)hydrochlorothiazide increases levels of piperacillin by decreasing renal clearance. Minor/Significance Unknown.

• pirbuterol

  Monitor Closely (1)pirbuterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)pirbuterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• piroxicam

  Monitor Closely (4)olmesartan and piroxicam both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, piroxicam. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  piroxicam increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  piroxicam decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of piroxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• pivmecillinam

  Monitor Closely (1)pivmecillinam, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• porfimer

  Monitor Closely (1)hydrochlorothiazide, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

• potassium acid phosphate

  Monitor Closely (2)olmesartan and potassium acid phosphate both increase serum potassium. Use Caution/Monitor.
  
  potassium acid phosphate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• potassium chloride

  Monitor Closely (2)olmesartan and potassium chloride both increase serum potassium. Use Caution/Monitor.
  
  potassium chloride increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• potassium citrate

  Monitor Closely (2)potassium citrate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
  
  olmesartan and potassium citrate both increase serum potassium. Use Caution/Monitor.

• potassium citrate/citric acid

  Monitor Closely (1)olmesartan and potassium citrate/citric acid both increase serum potassium. Modify Therapy/Monitor Closely.

• potassium iodide

  Monitor Closely (1)potassium iodide and olmesartan both increase serum potassium. Use Caution/Monitor. Potassium salts may increase the hyperkalemic effects of ARBs; the effect may be the result of aldosterone suppression in patients receiving ARBs.

• potassium phosphates, IV

  Serious - Use Alternative (1)olmesartan and potassium phosphates, IV both increase serum potassium. Avoid or Use Alternate Drug.

• prednisolone

  Minor (1)prednisolone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• prednisone

  Minor (1)prednisone, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• probenecid

  Monitor Closely (1)hydrochlorothiazide will increase the level or effect of probenecid by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• procainamide

  Monitor Closely (1)hydrochlorothiazide will increase the level or effect of procainamide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• propranolol

  Monitor Closely (3)propranolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and propranolol both increase serum potassium. Use Caution/Monitor.
  
  propranolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• quinapril

  Serious - Use Alternative (1)olmesartan, quinapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• quinidine

  Monitor Closely (1)quinidine will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

• quinine

  Minor (1)hydrochlorothiazide will increase the level or effect of quinine by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ramipril

  Serious - Use Alternative (1)olmesartan, ramipril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• reishi

  Minor (2)reishi increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.
  
  reishi increases effects of olmesartan by pharmacodynamic synergism. Minor/Significance Unknown.

• repaglinide

  Minor (1)hydrochlorothiazide decreases effects of repaglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• rose hips

  Minor (1)rose hips will increase the level or effect of hydrochlorothiazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• rosiglitazone

  Minor (1)hydrochlorothiazide decreases effects of rosiglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• sacubitril/valsartan

  Monitor Closely (2)olmesartan and sacubitril/valsartan both increase serum potassium. Use Caution/Monitor.
  
  sacubitril/valsartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salicylates (non-asa)

  Monitor Closely (2)olmesartan and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.
  
  salicylates (non-asa) increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of salicylates (non-asa) by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• salmeterol

  Monitor Closely (1)salmeterol and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (1)salmeterol, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• salsalate

  Monitor Closely (4)olmesartan and salsalate both increase serum potassium. Use Caution/Monitor.
  
  salsalate increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan, salsalate. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  salsalate decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of salsalate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• saxagliptin

  Minor (1)hydrochlorothiazide decreases effects of saxagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• shark cartilage

  Monitor Closely (1)hydrochlorothiazide, shark cartilage. Other (see comment). Use Caution/Monitor. Comment: May lead to hypercalcemia (theoretical).

• shepherd's purse

  Minor (2)shepherd's purse, hydrochlorothiazide. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.
  
  shepherd's purse, olmesartan. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.

• sitagliptin

  Minor (1)hydrochlorothiazide decreases effects of sitagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (2)sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  Monitor Closely (2)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of hydrochlorothiazide by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol

  Monitor Closely (1)hydrochlorothiazide and sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol both decrease serum potassium. Modify Therapy/Monitor Closely.

• sofosbuvir/velpatasvir

  Monitor Closely (1)sofosbuvir/velpatasvir increases levels of olmesartan by Other (see comment). Use Caution/Monitor. Comment: Velpatasvir inhibits OATP1B1, OATP1B3, and OATP2B1 transporters. .

• sotalol

  Monitor Closely (3)sotalol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sotalol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan and sotalol both increase serum potassium. Use Caution/Monitor.

• spironolactone

  Monitor Closely (2)olmesartan and spironolactone both increase serum potassium. Modify Therapy/Monitor Closely.
  
  spironolactone increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• squill

  Serious - Use Alternative (1)hydrochlorothiazide increases toxicity of squill by Other (see comment). Avoid or Use Alternate Drug. Comment: Potassium depletion may enhance toxicity of squill.

• succinylcholine

  Monitor Closely (1)succinylcholine increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• sulfadiazine

  Minor (1)hydrochlorothiazide increases levels of sulfadiazine by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfamethoxazole

  Minor (3)sulfamethoxazole will increase the level or effect of hydrochlorothiazide by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide increases levels of sulfamethoxazole by unspecified interaction mechanism. Minor/Significance Unknown.
  
  hydrochlorothiazide, sulfamethoxazole. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• sulfasalazine

  Monitor Closely (4)olmesartan, sulfasalazine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  olmesartan and sulfasalazine both increase serum potassium. Use Caution/Monitor.
  
  sulfasalazine decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  sulfasalazine increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• sulfisoxazole

  Minor (1)hydrochlorothiazide increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sulindac

  Monitor Closely (4)olmesartan, sulindac. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  sulindac increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sulindac decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and sulindac both increase serum potassium. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of sulindac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• synthetic human angiotensin II

  Monitor Closely (1)olmesartan decreases effects of synthetic human angiotensin II by pharmacodynamic antagonism. Use Caution/Monitor.

• tadalafil

  Monitor Closely (2)tadalafil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
  
  tadalafil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• telmisartan

  Monitor Closely (1)telmisartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• temocillin

  Monitor Closely (1)temocillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• terbutaline

  Monitor Closely (2)olmesartan increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  terbutaline and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.Minor (2)hydrochlorothiazide, terbutaline. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive hypokalemic effects.
  
  terbutaline, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• ticarcillin

  Monitor Closely (1)ticarcillin, hydrochlorothiazide. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• timolol

  Monitor Closely (3)timolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  timolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and timolol both increase serum potassium. Use Caution/Monitor.

• tizanidine

  Monitor Closely (1)tizanidine increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.Minor (1)tizanidine increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.

• tolazamide

  Minor (1)hydrochlorothiazide decreases effects of tolazamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• tolbutamide

  Minor (1)hydrochlorothiazide decreases effects of tolbutamide by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• tolfenamic acid

  Monitor Closely (2)olmesartan and tolfenamic acid both increase serum potassium. Use Caution/Monitor.
  
  tolfenamic acid increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of tolfenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolmetin

  Monitor Closely (4)olmesartan and tolmetin both increase serum potassium. Use Caution/Monitor.
  
  olmesartan, tolmetin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  tolmetin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  tolmetin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.Minor (1)hydrochlorothiazide will increase the level or effect of tolmetin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolvaptan

  Monitor Closely (2)olmesartan and tolvaptan both increase serum potassium. Use Caution/Monitor.
  
  tolvaptan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• toremifene

  Monitor Closely (1)hydrochlorothiazide, toremifene. Other (see comment). Use Caution/Monitor. Comment: Thiazide diuretics decrease renal calcium excretion and may increase risk of hypercalcemia in patients taking toremifene.

• torsemide

  Monitor Closely (2)olmesartan increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  torsemide and hydrochlorothiazide both decrease serum potassium. Use Caution/Monitor.

• trandolapril

  Serious - Use Alternative (1)olmesartan, trandolapril. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Dual blockade of renin-angiotensin system increases risks of hypotension, hyperkalemia, and renal impairment.

• treprostinil

  Monitor Closely (1)treprostinil increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.Minor (1)treprostinil increases effects of hydrochlorothiazide by pharmacodynamic synergism. Minor/Significance Unknown.

• tretinoin

  Serious - Use Alternative (1)hydrochlorothiazide, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• tretinoin topical

  Serious - Use Alternative (1)hydrochlorothiazide, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

• triamcinolone acetonide injectable suspension

  Minor (1)triamcinolone acetonide injectable suspension, hydrochlorothiazide. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia, especially with strong glucocorticoid activity.

• triamterene

  Monitor Closely (2)olmesartan and triamterene both increase serum potassium. Modify Therapy/Monitor Closely.
  
  triamterene increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.Minor (1)hydrochlorothiazide will increase the level or effect of triamterene by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• trientine

  Monitor Closely (1)hydrochlorothiazide decreases levels of trientine by increasing renal clearance. Use Caution/Monitor.

• trilostane

  Minor (1)trilostane, hydrochlorothiazide. Other (see comment). Minor/Significance Unknown. Comment: Trilostane reduces K+ loss while maintaining the natriuretic effect. Mechanism: inhibition of mineralocorticoid steroid synthesis.

• trimethoprim

  Monitor Closely (1)trimethoprim and olmesartan both increase serum potassium. Use Caution/Monitor. Trimethoprim decreases urinary potassium excretion. May cause hyperkalemia, particularly with high doses, renal insufficiency, or when combined with other drugs that cause hyperkalemia.Minor (2)hydrochlorothiazide will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  hydrochlorothiazide, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• umeclidinium bromide/vilanterol inhaled

  Monitor Closely (1)umeclidinium bromide/vilanterol inhaled and hydrochlorothiazide both decrease serum potassium. Modify Therapy/Monitor Closely. Electrocardiographic changes and/or hypokalemia associated with non?potassium-sparing diuretics may worsen with concomitant beta-agonists, particularly if recommended dose is exceeded

• valganciclovir

  Minor (1)hydrochlorothiazide will increase the level or effect of valganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• valsartan

  Monitor Closely (1)valsartan increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• verapamil

  Minor (1)hydrochlorothiazide will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• verteporfin

  Minor (1)hydrochlorothiazide, verteporfin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased phototoxicity.

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (1)vilanterol/fluticasone furoate inhaled and hydrochlorothiazide both decrease serum potassium. Modify Therapy/Monitor Closely. Beta-agonists may acutely worsen ECG changes and/or hypokalemia resulting from non-potassium-sparing diuretics

• vildagliptin

  Minor (1)hydrochlorothiazide decreases effects of vildagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• vitamin D

  Monitor Closely (1)hydrochlorothiazide increases effects of vitamin D by Other (see comment). Use Caution/Monitor. Comment: Combination may increase hypercalcemic effect of vitamin D analogs. Use with caution.

• voclosporin

  Monitor Closely (2)voclosporin and olmesartan both increase serum potassium. Use Caution/Monitor.
  
  voclosporin, olmesartan. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.Minor (1)voclosporin will increase the level or effect of olmesartan by Other (see comment). Minor/Significance Unknown. Information suggests voclosporin (an OATP1B1 inhibitor) may increase in the concentration of OATP1B1 substrates is possible. Monitor for adverse reactions of OATP1B1 substrates when coadministered with voclosporin.

• willow bark

  Minor (1)hydrochlorothiazide will increase the level or effect of willow bark by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• xipamide

  Monitor Closely (2)xipamide increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor.
  
  xipamide increases effects of olmesartan by pharmacodynamic synergism. Use Caution/Monitor.