atenolol/chlorthalidone (Rx)

Hypertension

Not indicated for initial therapy

If the fixed dose combination represents the dose appropriate to the individual patient's needs, it may be more convenient than the separate components

Initial dose: 50 mg atenolol/25 mg chlorthalidone PO qDay

May increase to 100 mg atenolol/25 mg chlorthalidone PO qDay if needed

When necessary, another antihypertensive agent may be added gradually beginning with 50 percent of the usual recommended starting dose to avoid an excessive fall in blood pressure

Renal Impairment

Use caution in dosing/titrating patients with renal dysfunction

Cumulative effects of thiazides may develop with impaired renal function

CrCl > 35 mL/min/1.73 m²: Dose adjustment not necessary

CrCl 15-35 mL/min/1.73 m²: Maximum 50 mg PO qDay

CrCl <15 mL/min/1.73 m²: Maximum 25 mg PO qDay or 50 mg PO every other day

Anuria: Contraindicated

Hepatic Impairment

Not studied; use caution

Administration

Combination may be substituted for the titrated individual components

Withdraw gradually over a period of about 2 weeks

May need dosage reduction for geriatric patients

<18 years: Safety/efficacy not established

Contraindicated (0)

Serious - Use Alternative (30)

• acebutolol

  acebutolol and atenolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• aminolevulinic acid oral

  aminolevulinic acid oral, chlorthalidone. 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

  chlorthalidone 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.

• betaxolol

  atenolol and betaxolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• bisoprolol

  atenolol and bisoprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• carvedilol

  atenolol and carvedilol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• celiprolol

  atenolol and celiprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• clonidine

  clonidine, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• digoxin

  digoxin, atenolol. Either decreases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• diltiazem

  diltiazem, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• esmolol

  atenolol and esmolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• fexinidazole

  fexinidazole, atenolol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to induce bradycardia. .

• isocarboxazid

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

• labetalol

  atenolol and labetalol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• lofexidine

  lofexidine, chlorthalidone. 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, atenolol. 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

  chlorthalidone, 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.

• metoprolol

  atenolol and metoprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• nadolol

  atenolol and nadolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• nebivolol

  atenolol and nebivolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• penbutolol

  atenolol and penbutolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• pindolol

  atenolol and pindolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• propranolol

  atenolol and propranolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• rivastigmine

  atenolol increases toxicity of rivastigmine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive bradycardia effect may result in syncope.

• saquinavir

  saquinavir, atenolol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of PR prolongation and cardiac arrhythmias.

• sotalol

  atenolol and sotalol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• squill

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

• timolol

  atenolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• tretinoin

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

• tretinoin topical

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

• verapamil

  verapamil, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

Monitor Closely (237)

• acebutolol

  acebutolol and atenolol both increase serum potassium. Use Caution/Monitor.
  
  acebutolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• aceclofenac

  aceclofenac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aceclofenac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and aceclofenac both increase serum potassium. Use Caution/Monitor.

• acemetacin

  atenolol and acemetacin both increase serum potassium. Use Caution/Monitor.
  
  acemetacin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  acemetacin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• albiglutide

  chlorthalidone 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.

• albuterol

  atenolol increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of albuterol by pharmacodynamic antagonism. Use Caution/Monitor.

• albuterol

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

• aldesleukin

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

• alfuzosin

  alfuzosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• amifostine

  amifostine, chlorthalidone. 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.

• aluminum hydroxide

  aluminum hydroxide decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• amifostine

  amifostine, atenolol. 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 chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
  
  atenolol and amiloride both increase serum potassium. Modify Therapy/Monitor Closely.

• amiodarone

  amiodarone, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of cardiotoxicity with bradycardia.

• arformoterol

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

• amlodipine

  atenolol, amlodipine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• amobarbital

  amobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of amobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• arformoterol

  atenolol increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of arformoterol by pharmacodynamic antagonism. Use Caution/Monitor.

• asenapine

  asenapine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• aspirin

  atenolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• aspirin rectal

  aspirin rectal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  atenolol and aspirin rectal both increase serum potassium. Use Caution/Monitor.
  
  aspirin rectal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• aspirin/citric acid/sodium bicarbonate

  aspirin/citric acid/sodium bicarbonate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and aspirin/citric acid/sodium bicarbonate both increase serum potassium. Use Caution/Monitor.
  
  aspirin/citric acid/sodium bicarbonate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• atazanavir

  atazanavir increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypotension, bradycardia, AV block, and prolonged PR interval. Consider lowering beta blocker dose.

• atenolol

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

• avanafil

  avanafil increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
  
  avanafil increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• beclomethasone, inhaled

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

• bendroflumethiazide

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

• benazepril

  benazepril, chlorthalidone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects. Increased risk of nephrotoxicity. Monitor blood pressure and renal function.

• bendroflumethiazide

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

• betaxolol

  betaxolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and betaxolol both increase serum potassium. Use Caution/Monitor.

• bismuth subsalicylate

  bismuth subsalicylate, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• bisoprolol

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

• bisoprolol

  atenolol and bisoprolol both increase serum potassium. Use Caution/Monitor.

• bretylium

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

• bumetanide

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

• buprenorphine, long-acting injection

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

• butabarbital

  butabarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butabarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• butalbital

  butalbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butalbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• calcifediol

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

• calcium acetate

  calcium acetate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.

• calcium carbonate

  calcium carbonate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• calcium chloride

  calcium chloride decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.

• calcium citrate

  calcium citrate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.

• calcium gluconate

  calcium gluconate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.

• candesartan

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

• captopril

  captopril, chlorthalidone. Either increases toxicity 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

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

• carbenoxolone

  chlorthalidone and carbenoxolone both decrease serum potassium. Use Caution/Monitor.

• carbidopa

  carbidopa increases effects of chlorthalidone 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.
  
  carbidopa increases effects of atenolol 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

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

• celecoxib

  celecoxib increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and celecoxib both increase serum potassium. Use Caution/Monitor.
  
  celecoxib decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• celiprolol

  celiprolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorthalidone decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atenolol and celiprolol both increase serum potassium. Use Caution/Monitor.

• chlorothiazide

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

• chlorthalidone

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

• cholestyramine

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

• choline magnesium trisalicylate

  choline magnesium trisalicylate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  choline magnesium trisalicylate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.

• clevidipine

  atenolol, clevidipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• cornsilk

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

• clonidine

  atenolol, clonidine. Mechanism: pharmacodynamic synergism. Modify Therapy/Monitor Closely. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.
  
  clonidine, atenolol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Sympatholytic action may worsen sinus node dysfunction and atrioventricular (AV) block.

• cyclopenthiazide

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

• dasiglucagon

  atenolol decreases effects of dasiglucagon by unknown mechanism. Use Caution/Monitor. Dasiglucagon may stimulate catecholamine release; whereas beta blockers may inhibit catecholamines released in response to dasiglucagon. Coadministration may also transiently increase pulse and BP.

• deflazacort

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

• desflurane

  desflurane, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• dichlorphenamide

  dichlorphenamide and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  dichlorphenamide and atenolol both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  diclofenac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and diclofenac both increase serum potassium. Use Caution/Monitor.
  
  diclofenac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• diflunisal

  diflunisal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  diflunisal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and diflunisal both increase serum potassium. Use Caution/Monitor.

• digoxin

  digoxin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and digoxin both increase serum potassium. Use Caution/Monitor.
  
  atenolol increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Enhanced bradycardia.
  
  chlorthalidone increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Hypokalemia increases digoxin effects.

• diltiazem

  atenolol and diltiazem both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• dobutamine

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

• disopyramide

  atenolol increases effects of disopyramide by pharmacodynamic synergism. Use Caution/Monitor. Additive negative inotropic effects.

• dobutamine

  atenolol increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of dobutamine by pharmacodynamic antagonism. Use Caution/Monitor.

• dopexamine

  dopexamine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of dopexamine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• doxazosin

  doxazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• drospirenone

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

• drospirenone

  atenolol and drospirenone both increase serum potassium. Modify Therapy/Monitor Closely.

• empagliflozin

  empagliflozin, chlorthalidone. 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.

• ephedrine

  ephedrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of ephedrine by pharmacodynamic antagonism. Use Caution/Monitor.

• epinephrine

  epinephrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine racemic

  atenolol decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor.
  
  epinephrine racemic and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• eprosartan

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

• esmolol

  atenolol and esmolol both increase serum potassium. Use Caution/Monitor.
  
  esmolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ethacrynic acid

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

• ether

  atenolol, ether. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both beta blockers and ether depress the myocardium; consider lowering beta blocker dose if ether used for anesthesia.

• etodolac

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

• etodolac

  atenolol and etodolac both increase serum potassium. Use Caution/Monitor.
  
  etodolac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• etomidate

  etomidate, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• exenatide injectable solution

  chlorthalidone 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

  chlorthalidone 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.

• felodipine

  atenolol and felodipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• fenbufen

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

• fenoprofen

  fenoprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and fenoprofen both increase serum potassium. Use Caution/Monitor.
  
  fenoprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• fentanyl

  fentanyl decreases effects of chlorthalidone 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).

• fingolimod

  fingolimod, atenolol. pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease heart rate. Monitor for bradycardia.
  
  atenolol increases effects of fingolimod by pharmacodynamic synergism. Use Caution/Monitor. Both medications decrease heart rate. Monitor patients on concomitant therapy, particularly in the first 6 hours after fingolimod is initiated or after a treatment interruption of at least two weeks, for bradycardia and atrioventricular block. To identify underlying risk factors of bradycardia and AV block, obtain a new or recent ECG in patients using beta-blockers prior to starting fingolimod.

• fentanyl intranasal

  fentanyl intranasal decreases effects of chlorthalidone 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 chlorthalidone 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 chlorthalidone 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

  flurbiprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  flurbiprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and flurbiprofen both increase serum potassium. Use Caution/Monitor.

• formoterol

  formoterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of formoterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• furosemide

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

• gentamicin

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

• glucagon

  glucagon decreases toxicity of atenolol by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Coadministration of glucagon with beta-blockers may have transiently increased pulse and blood pressure.

• hydrochlorothiazide

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

• glucagon intranasal

  glucagon intranasal decreases toxicity of atenolol by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Coadministration of glucagon with beta-blockers may have transiently increased pulse and blood pressure.

• glycopyrrolate

  glycopyrrolate increases levels of atenolol by unknown mechanism. Use Caution/Monitor.

• glycopyrrolate inhaled

  glycopyrrolate inhaled increases levels of atenolol by unknown mechanism. Use Caution/Monitor.

• hydralazine

  hydralazine increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects.

• hydrochlorothiazide

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

• ibuprofen

  ibuprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ibuprofen both increase serum potassium. Use Caution/Monitor.
  
  ibuprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ibuprofen IV

  ibuprofen IV increases and chlorthalidone 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.
  
  ibuprofen IV decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ibuprofen IV both increase serum potassium. Use Caution/Monitor.
  
  chlorthalidone will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• indacaterol, inhaled

  indacaterol, inhaled, chlorthalidone. Other (see comment). Use Caution/Monitor. Comment: Caution is advised in the coadministration of indacaterol neohaler with non-potassium-sparing diuretics.
  
  indacaterol, inhaled, atenolol. Other (see comment). Use Caution/Monitor. Comment: Beta-blockers and indacaterol may interfere with the effect of each other when administered concurrently. Beta-blockers may produce severe bronchospasm in COPD patients. Therefore, patients with COPD should not normally be treated with beta-blockers. However, under certain circumstances, e.g. as prophylaxis after myocardial infarction, there may be no acceptable alternatives to the use of beta-blockers in patients with COPD. In this setting, cardioselective beta-blockers could be considered, although they should be administered with caution.
  
  chlorthalidone, indacaterol, inhaled. serum potassium. Use Caution/Monitor. Combination may increase risk of hypokalemia.

• indapamide

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

• indomethacin

  indomethacin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  indomethacin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and indomethacin both increase serum potassium. Use Caution/Monitor.

• insulin degludec

  chlorthalidone 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.
  
  atenolol, insulin degludec. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• insulin degludec/insulin aspart

  chlorthalidone 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.
  
  atenolol, insulin degludec/insulin aspart. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• insulin inhaled

  chlorthalidone 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.
  
  atenolol, insulin inhaled. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• iodixanol

  atenolol increases toxicity of iodixanol by unspecified interaction mechanism. Use Caution/Monitor. Use of beta-blockers lowers the threshold for and increases the severity of contrast reactions, and reduces the responsiveness of treatment of hypersensitivity reactions with epinephrine. .

• irbesartan

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

• irbesartan

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

• isoproterenol

  atenolol increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of isoproterenol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  isoproterenol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.

• isradipine

  atenolol, isradipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• juniper

  juniper, chlorthalidone. 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.

• ivabradine

  ivabradine, atenolol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Most patients receiving ivabradine will also be treated with a beta-blocker. The risk of bradycardia increases with coadministration of drugs that slow heart rate (eg, digoxin, amiodarone, beta-blockers). Monitor heart rate in patients taking ivabradine with other negative chronotropes.

• ketamine

  ketamine, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• ketoprofen

  ketoprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketoprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ketoprofen both increase serum potassium. Use Caution/Monitor.

• ketorolac

  atenolol and ketorolac both increase serum potassium. Use Caution/Monitor.
  
  ketorolac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketorolac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• ketorolac intranasal

  atenolol and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.
  
  ketorolac intranasal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  ketorolac intranasal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• labetalol

  atenolol and labetalol both increase serum potassium. Use Caution/Monitor.
  
  labetalol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lasmiditan

  atenolol increases effects of lasmiditan by pharmacodynamic synergism. Use Caution/Monitor. Lasmiditan has been associated with a lowering of heart rate (HR). In a drug interaction study, addition of a single 200-mg dose of lasmiditan to propranolol decreased HR by an additional 5 bpm compared to propranolol alone, for a mean maximum of 19 bpm.

• levalbuterol

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

• levalbuterol

  atenolol increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of levalbuterol by pharmacodynamic antagonism. Use Caution/Monitor.

• levodopa

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

• lily of the valley

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

• lornoxicam

  atenolol and lornoxicam both increase serum potassium. Use Caution/Monitor.
  
  lornoxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• liraglutide

  chlorthalidone 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

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

• lornoxicam

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

• losartan

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

• lurasidone

  lurasidone increases effects of atenolol 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 chlorthalidone 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 chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).

• maraviroc

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

• maraviroc

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

• meclofenamate

  atenolol and meclofenamate both increase serum potassium. Use Caution/Monitor.
  
  meclofenamate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  meclofenamate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mefenamic acid

  mefenamic acid decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
  
  mefenamic acid increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mefloquine

  mefloquine increases levels of atenolol by decreasing metabolism. Use Caution/Monitor. Risk of arrhythmia.

• meloxicam

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

• meloxicam

  atenolol and meloxicam both increase serum potassium. Use Caution/Monitor.
  
  meloxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• metaproterenol

  metaproterenol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of metaproterenol by pharmacodynamic antagonism. Use Caution/Monitor.

• methoxsalen

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

• methyclothiazide

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

• methyclothiazide

  chlorthalidone and methyclothiazide both decrease serum potassium. Use Caution/Monitor.

• metolazone

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

• metoprolol

  metoprolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and metoprolol both increase serum potassium. Use Caution/Monitor.

• mometasone inhaled

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

• moxisylyte

  moxisylyte and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• mycophenolate

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

• nabumetone

  nabumetone increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nabumetone decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and nabumetone both increase serum potassium. Use Caution/Monitor.

• nadolol

  nadolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and nadolol both increase serum potassium. Use Caution/Monitor.

• naproxen

  atenolol and naproxen both increase serum potassium. Use Caution/Monitor.
  
  naproxen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  naproxen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• nebivolol

  nebivolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and nebivolol both increase serum potassium. Use Caution/Monitor.

• nicardipine

  atenolol, nicardipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nitazoxanide

  nitazoxanide, chlorthalidone. Either increases levels of the other by Mechanism: plasma protein binding competition. Use Caution/Monitor.

• nifedipine

  atenolol, nifedipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nimodipine

  atenolol, nimodipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nisoldipine

  atenolol, nisoldipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nitroglycerin rectal

  nitroglycerin rectal, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Beta-blockers blunt the reflex tachycardia produced by nitroglycerin without preventing its hypotensive effects. If beta-blockers are used with nitroglycerin in patients with angina pectoris, additional hypotensive effects may occur.
  
  nitroglycerin rectal, chlorthalidone. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Observe for possible additive hypotensive effects during concomitant use. .

• norepinephrine

  norepinephrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of norepinephrine by pharmacodynamic antagonism. Use Caution/Monitor.

• oliceridine

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

• olmesartan

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

• olodaterol inhaled

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

• ospemifene

  chlorthalidone, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely.

• oxaprozin

  atenolol and oxaprozin both increase serum potassium. Use Caution/Monitor.
  
  oxaprozin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  oxaprozin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• oxymetazoline topical

  oxymetazoline topical increases and atenolol decreases sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• parecoxib

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

• parecoxib

  atenolol and parecoxib both increase serum potassium. Use Caution/Monitor.
  
  parecoxib decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• penbutolol

  penbutolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and penbutolol both increase serum potassium. Use Caution/Monitor.

• pentobarbital

  pentobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of pentobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• pindolol

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

• phenobarbital

  phenobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of phenobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• phenoxybenzamine

  phenoxybenzamine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• phentolamine

  phentolamine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• pindolol

  atenolol and pindolol both increase serum potassium. Use Caution/Monitor.

• pirbuterol

  atenolol increases and pirbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of pirbuterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  pirbuterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.

• piroxicam

  piroxicam increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  piroxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and piroxicam both increase serum potassium. Use Caution/Monitor.

• pivmecillinam

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

• ponesimod

  ponesimod and atenolol both increase pharmacodynamic synergism. Use Caution/Monitor. Beta-blockers may have additive effects on lowering HR. Consider resting HR before initiating ponesimod in patients on stable dose of beta-blocker. Refer to the ponesimod prescribing information for more dosing information.

• porfimer

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

• potassium acid phosphate

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

• potassium chloride

  atenolol and potassium chloride both increase serum potassium. Modify Therapy/Monitor Closely.
  
  potassium chloride increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.

• potassium citrate

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

• prazosin

  prazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• probenecid

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

• primidone

  primidone decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of primidone. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• propofol

  propofol, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• propranolol

  atenolol and propranolol both increase serum potassium. Use Caution/Monitor.
  
  propranolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• sacubitril/valsartan

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

• salicylates (non-asa)

  salicylates (non-asa) decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  salicylates (non-asa) increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.

• salmeterol

  salmeterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of salmeterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salsalate

  salsalate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  salsalate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and salsalate both increase serum potassium. Use Caution/Monitor.

• secobarbital

  secobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of secobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• shark cartilage

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

• sevoflurane

  sevoflurane, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• sildenafil

  atenolol increases effects of sildenafil by additive vasodilation. Use Caution/Monitor. Sildenafil has systemic vasodilatory properties and may further lower blood pressure in patients taking antihypertensive medications. Monitor blood pressure response to sildenafil in patients receiving concurrent blood pressure lowering therapy.

• silodosin

  silodosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• siponimod

  siponimod, atenolol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Caution when siponimod is initiated in patients receiving beta-blocker treatment because of additive effects on lowering heart rate. Temporary interruption of beta-blocker may be needed before initiating siponimod. Beta-blocker treatment can be initiated in patients receiving stable doses of siponimod.

• sodium bicarbonate

  sodium bicarbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium citrate/citric acid

  sodium citrate/citric acid decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of chlorthalidone 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 chlorthalidone 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

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

• sotalol

  atenolol and sotalol both increase serum potassium. Use Caution/Monitor.
  
  sotalol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• spironolactone

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

• succinylcholine

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

• sulfasalazine

  atenolol and sulfasalazine both increase serum potassium. Use Caution/Monitor.
  
  sulfasalazine increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sulfasalazine decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• sulindac

  atenolol and sulindac both increase serum potassium. Use Caution/Monitor.
  
  sulindac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sulindac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• tadalafil

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

• telmisartan

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

• temocillin

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

• terazosin

  terazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• terbutaline

  atenolol increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of terbutaline by pharmacodynamic antagonism. Use Caution/Monitor.
  
  terbutaline and chlorthalidone both decrease serum potassium. Use Caution/Monitor.

• theophylline

  atenolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.

• ticarcillin

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

• timolol

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

• tolfenamic acid

  tolfenamic acid increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  tolfenamic acid decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and tolfenamic acid both increase serum potassium. Use Caution/Monitor.

• tolmetin

  tolmetin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and tolmetin both increase serum potassium. Use Caution/Monitor.
  
  tolmetin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tolvaptan

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

• toremifene

  chlorthalidone, 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

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

• torsemide

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

• triamterene

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

• trientine

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

• valsartan

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

• umeclidinium bromide/vilanterol inhaled

  umeclidinium bromide/vilanterol inhaled and chlorthalidone 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 chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• verapamil

  atenolol and verapamil both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• vilanterol/fluticasone furoate inhaled

  vilanterol/fluticasone furoate inhaled and chlorthalidone 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

  chlorthalidone 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.

• xipamide

  xipamide increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor.
  
  xipamide increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor.

Minor (170)

• acarbose

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

• aceclofenac

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

• acemetacin

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

• acyclovir

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

• adenosine

  atenolol, adenosine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Bradycardia.

• agrimony

  agrimony increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.
  
  agrimony increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• albuterol

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

• ampicillin

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

• aminohippurate sodium

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

• anticholinergic/sedative combos

  anticholinergic/sedative combos decreases levels of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• antipyrine

  atenolol increases levels of antipyrine by decreasing metabolism. Minor/Significance Unknown.

• arformoterol

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

• aspirin

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

• aspirin rectal

  chlorthalidone 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

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

• atropine

  atropine increases levels of atenolol by unknown mechanism. Minor/Significance Unknown.

• atropine IV/IM

  atropine IV/IM increases levels of atenolol by unknown mechanism. Minor/Significance Unknown.

• balsalazide

  chlorthalidone 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 chlorthalidone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• birch

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

• bitter melon

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

• brimonidine

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

• budesonide

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

• cevimeline

  cevimeline increases effects of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• calcitriol topical

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

• calcium acetate

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

• calcium carbonate

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

• calcium chloride

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

• calcium citrate

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

• calcium gluconate

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

• carbenoxolone

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

• cefadroxil

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

• cefamandole

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

• cefpirome

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

• celecoxib

  chlorthalidone 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 chlorthalidone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorothiazide

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

• chlorpropamide

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

• choline magnesium trisalicylate

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

• cocaine

  atenolol increases effects of cocaine by pharmacodynamic synergism. Minor/Significance Unknown. Risk of angina.

• colestipol

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

• cornsilk

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

• corticotropin

  corticotropin, chlorthalidone. pharmacodynamic synergism. Minor/Significance Unknown. Possible enhanced electrolyte loss.

• cortisone

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

• cosyntropin

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

• cyclopenthiazide

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

• deflazacort

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

• dexamethasone

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

• diazoxide

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

• diclofenac

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

• diflunisal

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

• dihydroergotamine

  dihydroergotamine, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.

• dihydroergotamine intranasal

  dihydroergotamine intranasal, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.

• dipyridamole

  dipyridamole, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of bradycardia.

• dobutamine

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

• dopexamine

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

• ephedrine

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

• epinephrine

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

• epinephrine racemic

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

• epoprostenol

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

• escitalopram

  escitalopram increases levels of atenolol by decreasing metabolism. Minor/Significance Unknown.

• etodolac

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

• fenbufen

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

• fenoldopam

  fenoldopam increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.

• fenoprofen

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

• flavoxate

  flavoxate increases effects of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• fludrocortisone

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

• flurbiprofen

  chlorthalidone 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 chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia (theoretical).

• folic acid

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

• formoterol

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

• forskolin

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

• ganciclovir

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

• guanfacine

  atenolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.

• glimepiride

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

• glipizide

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

• glyburide

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

• goldenrod

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

• hydrochlorothiazide

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

• hydrocortisone

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

• ibuprofen

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

• imaging agents (gadolinium)

  atenolol, imaging agents (gadolinium). Mechanism: unknown. Minor/Significance Unknown. Increased risk of anaphylaxis from contrast media.

• indapamide

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

• indomethacin

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

• insulin aspart

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

• insulin detemir

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

• insulin glargine

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

• insulin glulisine

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

• insulin lispro

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

• insulin NPH

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

• insulin regular human

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

• isoproterenol

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

• ketoprofen

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

• ketorolac

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

• ketorolac intranasal

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

• L-methylfolate

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

• levalbuterol

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

• levobetaxolol

  levobetaxolol increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• lornoxicam

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

• magnesium chloride

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

• magnesium citrate

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

• magnesium hydroxide

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

• magnesium oxide

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

• magnesium sulfate

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

• maitake

  maitake increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• meclofenamate

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

• mefenamic acid

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

• melatonin

  melatonin decreases toxicity of atenolol by pharmacodynamic antagonism. Minor/Significance Unknown. Melatonin may correct beta blocker induced sleep disturbances.

• meloxicam

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

• mesalamine

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

• metaproterenol

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

• metformin

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

• methyclothiazide

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

• methylprednisolone

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

• metipranolol ophthalmic

  metipranolol ophthalmic increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• metolazone

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

• miglitol

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

• minoxidil

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

• nabumetone

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

• naproxen

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

• nateglinide

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

• neostigmine

  atenolol, neostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.

• noni juice

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

• norepinephrine

  norepinephrine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• octacosanol

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

• octacosanol

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

• oxaprozin

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

• oxybutynin

  atenolol increases levels of oxybutynin by decreasing metabolism. Minor/Significance Unknown.

• oxybutynin topical

  atenolol increases levels of oxybutynin topical by decreasing metabolism. Minor/Significance Unknown.

• oxybutynin transdermal

  atenolol increases levels of oxybutynin transdermal by decreasing metabolism. Minor/Significance Unknown.

• parecoxib

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

• physostigmine

  atenolol, physostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.

• pilocarpine

  pilocarpine increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• pioglitazone

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

• pirbuterol

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

• piroxicam

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

• prednisolone

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

• prednisone

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

• reishi

  reishi increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.
  
  reishi increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.

• repaglinide

  chlorthalidone 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, atenolol. 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 chlorthalidone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• rosiglitazone

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

• salicylates (non-asa)

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

• salmeterol

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

• salsalate

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

• saxagliptin

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

• sitagliptin

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

• sulfadiazine

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

• sulfamethoxazole

  chlorthalidone increases levels of sulfamethoxazole by unspecified interaction mechanism. Minor/Significance Unknown.
  
  chlorthalidone, sulfamethoxazole. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• sulfasalazine

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

• sulfisoxazole

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

• sulindac

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

• terbutaline

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

• tizanidine

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

• tolazamide

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

• treprostinil

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

• tolbutamide

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

• tolfenamic acid

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

• tolmetin

  chlorthalidone 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 chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.

• triamcinolone acetonide injectable suspension

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

• trilostane

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

• trimethoprim

  chlorthalidone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• valganciclovir

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

• verteporfin

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

• vildagliptin

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

• willow bark

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

• yohimbe

  atenolol decreases toxicity of yohimbe by pharmacodynamic antagonism. Minor/Significance Unknown.

• acarbose

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

• acebutolol

  Monitor Closely (2)acebutolol and atenolol both increase serum potassium. Use Caution/Monitor.
  
  acebutolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)acebutolol and atenolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• aceclofenac

  Monitor Closely (3)aceclofenac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aceclofenac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and aceclofenac both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of aceclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acemetacin

  Monitor Closely (3)atenolol and acemetacin both increase serum potassium. Use Caution/Monitor.
  
  acemetacin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  acemetacin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of acemetacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acyclovir

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

• adenosine

  Minor (1)atenolol, adenosine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Bradycardia.

• agrimony

  Minor (2)agrimony increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.
  
  agrimony increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• albiglutide

  Monitor Closely (1)chlorthalidone 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.

• albuterol

  Monitor Closely (3)atenolol decreases effects of albuterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  albuterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)albuterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• aldesleukin

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

• alfuzosin

  Monitor Closely (1)alfuzosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• aluminum hydroxide

  Monitor Closely (1)aluminum hydroxide decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• amifostine

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

• aminohippurate sodium

  Minor (1)chlorthalidone 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, chlorthalidone. 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)chlorthalidone 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, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of cardiotoxicity with bradycardia.

• amlodipine

  Monitor Closely (1)atenolol, amlodipine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• amobarbital

  Monitor Closely (1)amobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of amobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• ampicillin

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

• anticholinergic/sedative combos

  Minor (1)anticholinergic/sedative combos decreases levels of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• antipyrine

  Minor (1)atenolol increases levels of antipyrine by decreasing metabolism. Minor/Significance Unknown.

• arformoterol

  Monitor Closely (3)arformoterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of arformoterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)arformoterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• asenapine

  Monitor Closely (1)asenapine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• aspirin

  Monitor Closely (3)atenolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• aspirin rectal

  Monitor Closely (3)aspirin rectal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  atenolol and aspirin rectal both increase serum potassium. Use Caution/Monitor.
  
  aspirin rectal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone 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 (3)aspirin/citric acid/sodium bicarbonate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and aspirin/citric acid/sodium bicarbonate both increase serum potassium. Use Caution/Monitor.
  
  aspirin/citric acid/sodium bicarbonate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of aspirin/citric acid/sodium bicarbonate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• atazanavir

  Monitor Closely (1)atazanavir increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypotension, bradycardia, AV block, and prolonged PR interval. Consider lowering beta blocker dose.

• atenolol

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

• atropine

  Minor (1)atropine increases levels of atenolol by unknown mechanism. Minor/Significance Unknown.

• atropine IV/IM

  Minor (1)atropine IV/IM increases levels of atenolol by unknown mechanism. Minor/Significance Unknown.

• avanafil

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

• balsalazide

  Minor (1)chlorthalidone 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 chlorthalidone by increasing elimination. Use Caution/Monitor. May increase the hypokalemic effects of thiazide diuretics.

• benazepril

  Monitor Closely (1)benazepril, chlorthalidone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Enhanced hypotensive effects. Increased risk of nephrotoxicity. Monitor blood pressure and renal function.

• bendroflumethiazide

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

• betaxolol

  Monitor Closely (2)betaxolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and betaxolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and betaxolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• birch

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

• bismuth subsalicylate

  Monitor Closely (1)bismuth subsalicylate, atenolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.

• bisoprolol

  Monitor Closely (2)bisoprolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and bisoprolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and bisoprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• bitter melon

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

• bretylium

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

• brimonidine

  Minor (2)brimonidine increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.
  
  brimonidine increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• budesonide

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

• bumetanide

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

• buprenorphine, long-acting injection

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

• butabarbital

  Monitor Closely (1)butabarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butabarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• butalbital

  Monitor Closely (1)butalbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of butalbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• calcifediol

  Monitor Closely (1)chlorthalidone 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, chlorthalidone. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Potential additive hypercalcemia.

• calcium acetate

  Monitor Closely (1)calcium acetate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.Minor (1)chlorthalidone increases levels of calcium acetate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium carbonate

  Monitor Closely (2)calcium carbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
  
  calcium carbonate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.Minor (1)chlorthalidone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium chloride

  Monitor Closely (1)calcium chloride decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.Minor (1)chlorthalidone increases levels of calcium chloride by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium citrate

  Monitor Closely (1)calcium citrate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.Minor (1)chlorthalidone increases levels of calcium citrate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• calcium gluconate

  Monitor Closely (1)calcium gluconate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.Minor (1)chlorthalidone increases levels of calcium gluconate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• candesartan

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

• captopril

  Monitor Closely (1)captopril, chlorthalidone. Either increases toxicity 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

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

• carbidopa

  Monitor Closely (2)carbidopa increases effects of chlorthalidone 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.
  
  carbidopa increases effects of atenolol 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 (2)carvedilol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and carvedilol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and carvedilol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• cefadroxil

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

• cefamandole

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

• cefpirome

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

• celecoxib

  Monitor Closely (3)celecoxib increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and celecoxib both increase serum potassium. Use Caution/Monitor.
  
  celecoxib decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of celecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celiprolol

  Monitor Closely (3)celiprolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  chlorthalidone decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
  
  atenolol and celiprolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and celiprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• cephalexin

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

• cevimeline

  Minor (1)cevimeline increases effects of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• chlorothiazide

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

• chlorpropamide

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

• chlorthalidone

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

• cholestyramine

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

• choline magnesium trisalicylate

  Monitor Closely (3)choline magnesium trisalicylate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  choline magnesium trisalicylate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of choline magnesium trisalicylate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• clevidipine

  Monitor Closely (1)atenolol, clevidipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• clonidine

  Monitor Closely (2)clonidine, atenolol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Sympatholytic action may worsen sinus node dysfunction and atrioventricular (AV) block.
  
  atenolol, clonidine. Mechanism: pharmacodynamic synergism. Modify Therapy/Monitor Closely. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.Serious - Use Alternative (1)clonidine, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• cocaine

  Minor (1)atenolol increases effects of cocaine by pharmacodynamic synergism. Minor/Significance Unknown. Risk of angina.

• colestipol

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

• cornsilk

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

• corticotropin

  Minor (1)corticotropin, chlorthalidone. pharmacodynamic synergism. Minor/Significance Unknown. Possible enhanced electrolyte loss.

• cortisone

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

• cosyntropin

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

• cyclopenthiazide

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

• dasiglucagon

  Monitor Closely (1)atenolol decreases effects of dasiglucagon by unknown mechanism. Use Caution/Monitor. Dasiglucagon may stimulate catecholamine release; whereas beta blockers may inhibit catecholamines released in response to dasiglucagon. Coadministration may also transiently increase pulse and BP.

• deflazacort

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

• desflurane

  Monitor Closely (1)desflurane, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• dexamethasone

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

• diazoxide

  Minor (1)diazoxide, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperglycemia.

• dichlorphenamide

  Monitor Closely (2)dichlorphenamide and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  dichlorphenamide and atenolol both decrease serum potassium. Use Caution/Monitor.

• diclofenac

  Monitor Closely (3)diclofenac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and diclofenac both increase serum potassium. Use Caution/Monitor.
  
  diclofenac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of diclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• diflunisal

  Monitor Closely (3)diflunisal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  diflunisal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and diflunisal both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of diflunisal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• digoxin

  Monitor Closely (4)digoxin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Enhanced bradycardia.
  
  atenolol and digoxin both increase serum potassium. Use Caution/Monitor.
  
  chlorthalidone increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Hypokalemia increases digoxin effects.Serious - Use Alternative (1)digoxin, atenolol. Either decreases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• dihydroergotamine

  Minor (1)dihydroergotamine, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.

• dihydroergotamine intranasal

  Minor (1)dihydroergotamine intranasal, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.

• diltiazem

  Monitor Closely (1)atenolol and diltiazem both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)diltiazem, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• dipyridamole

  Minor (1)dipyridamole, atenolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of bradycardia.

• disopyramide

  Monitor Closely (1)atenolol increases effects of disopyramide by pharmacodynamic synergism. Use Caution/Monitor. Additive negative inotropic effects.

• dobutamine

  Monitor Closely (3)atenolol increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of dobutamine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  dobutamine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.Minor (1)dobutamine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• dopexamine

  Monitor Closely (3)dopexamine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of dopexamine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)dopexamine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• doxazosin

  Monitor Closely (1)doxazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• drospirenone

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

• empagliflozin

  Monitor Closely (1)empagliflozin, chlorthalidone. 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.

• ephedrine

  Monitor Closely (3)ephedrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of ephedrine by pharmacodynamic antagonism. Use Caution/Monitor.Minor (1)ephedrine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine

  Monitor Closely (3)epinephrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)epinephrine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epinephrine racemic

  Monitor Closely (3)atenolol decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor.
  
  epinephrine racemic and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)epinephrine racemic, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• epoprostenol

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

• eprosartan

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

• escitalopram

  Minor (1)escitalopram increases levels of atenolol by decreasing metabolism. Minor/Significance Unknown.

• esmolol

  Monitor Closely (2)atenolol and esmolol both increase serum potassium. Use Caution/Monitor.
  
  esmolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and esmolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• ethacrynic acid

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

• ether

  Monitor Closely (1)atenolol, ether. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both beta blockers and ether depress the myocardium; consider lowering beta blocker dose if ether used for anesthesia.

• etodolac

  Monitor Closely (3)etodolac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  etodolac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and etodolac both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of etodolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• etomidate

  Monitor Closely (1)etomidate, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• exenatide injectable solution

  Monitor Closely (1)chlorthalidone 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 (1)chlorthalidone 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.

• felodipine

  Monitor Closely (1)atenolol and felodipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• fenbufen

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

• fenoldopam

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

• fenoprofen

  Monitor Closely (3)fenoprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and fenoprofen both increase serum potassium. Use Caution/Monitor.
  
  fenoprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone 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 chlorthalidone 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 chlorthalidone 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 chlorthalidone 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 chlorthalidone 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).

• fexinidazole

  Serious - Use Alternative (1)fexinidazole, atenolol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to induce bradycardia. .

• fingolimod

  Monitor Closely (2)fingolimod, atenolol. pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease heart rate. Monitor for bradycardia.
  
  atenolol increases effects of fingolimod by pharmacodynamic synergism. Use Caution/Monitor. Both medications decrease heart rate. Monitor patients on concomitant therapy, particularly in the first 6 hours after fingolimod is initiated or after a treatment interruption of at least two weeks, for bradycardia and atrioventricular block. To identify underlying risk factors of bradycardia and AV block, obtain a new or recent ECG in patients using beta-blockers prior to starting fingolimod.

• flavoxate

  Minor (1)flavoxate increases effects of atenolol by unspecified interaction mechanism. Minor/Significance Unknown.

• fludrocortisone

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

• flurbiprofen

  Monitor Closely (3)flurbiprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  flurbiprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and flurbiprofen both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone 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 chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypokalemia (theoretical).

• folic acid

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

• formoterol

  Monitor Closely (3)formoterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of formoterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)formoterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• forskolin

  Minor (2)forskolin increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.
  
  forskolin increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• furosemide

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

• ganciclovir

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

• gentamicin

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

• glimepiride

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

• glipizide

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

• glucagon

  Monitor Closely (1)glucagon decreases toxicity of atenolol by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Coadministration of glucagon with beta-blockers may have transiently increased pulse and blood pressure.

• glucagon intranasal

  Monitor Closely (1)glucagon intranasal decreases toxicity of atenolol by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Coadministration of glucagon with beta-blockers may have transiently increased pulse and blood pressure.

• glyburide

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

• glycopyrrolate

  Monitor Closely (1)glycopyrrolate increases levels of atenolol by unknown mechanism. Use Caution/Monitor.

• glycopyrrolate inhaled

  Monitor Closely (1)glycopyrrolate inhaled increases levels of atenolol by unknown mechanism. Use Caution/Monitor.

• goldenrod

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

• guanfacine

  Minor (1)atenolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.

• hydralazine

  Monitor Closely (1)hydralazine increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects.

• hydrochlorothiazide

  Monitor Closely (2)atenolol increases and hydrochlorothiazide 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.

• hydrocortisone

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

• ibuprofen

  Monitor Closely (3)ibuprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ibuprofen both increase serum potassium. Use Caution/Monitor.
  
  ibuprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of ibuprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ibuprofen IV

  Monitor Closely (4)ibuprofen IV increases and chlorthalidone 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.
  
  ibuprofen IV decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ibuprofen IV both increase serum potassium. Use Caution/Monitor.
  
  chlorthalidone will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• imaging agents (gadolinium)

  Minor (1)atenolol, imaging agents (gadolinium). Mechanism: unknown. Minor/Significance Unknown. Increased risk of anaphylaxis from contrast media.

• indacaterol, inhaled

  Monitor Closely (3)indacaterol, inhaled, chlorthalidone. Other (see comment). Use Caution/Monitor. Comment: Caution is advised in the coadministration of indacaterol neohaler with non-potassium-sparing diuretics.
  
  indacaterol, inhaled, atenolol. Other (see comment). Use Caution/Monitor. Comment: Beta-blockers and indacaterol may interfere with the effect of each other when administered concurrently. Beta-blockers may produce severe bronchospasm in COPD patients. Therefore, patients with COPD should not normally be treated with beta-blockers. However, under certain circumstances, e.g. as prophylaxis after myocardial infarction, there may be no acceptable alternatives to the use of beta-blockers in patients with COPD. In this setting, cardioselective beta-blockers could be considered, although they should be administered with caution.
  
  chlorthalidone, indacaterol, inhaled. serum potassium. Use Caution/Monitor. Combination may increase risk of hypokalemia.

• indapamide

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

• indomethacin

  Monitor Closely (3)indomethacin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  indomethacin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and indomethacin both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of indomethacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• insulin aspart

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

• insulin degludec

  Monitor Closely (2)chlorthalidone 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.
  
  atenolol, insulin degludec. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• insulin degludec/insulin aspart

  Monitor Closely (2)chlorthalidone 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.
  
  atenolol, insulin degludec/insulin aspart. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• insulin detemir

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

• insulin glargine

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

• insulin glulisine

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

• insulin inhaled

  Monitor Closely (2)chlorthalidone 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.
  
  atenolol, insulin inhaled. Other (see comment). Modify Therapy/Monitor Closely. Comment: Beta-blockers may either increase or decrease the blood glucose lowering effect of insulin; beta-blockers can prolong hypoglycemia (interference with glycogenolysis) or cause hyperglycemia (insulin secretion inhibited).

• insulin lispro

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

• insulin NPH

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

• insulin regular human

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

• iodixanol

  Monitor Closely (1)atenolol increases toxicity of iodixanol by unspecified interaction mechanism. Use Caution/Monitor. Use of beta-blockers lowers the threshold for and increases the severity of contrast reactions, and reduces the responsiveness of treatment of hypersensitivity reactions with epinephrine. .

• irbesartan

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

• isocarboxazid

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

• isoproterenol

  Monitor Closely (3)atenolol increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of isoproterenol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  isoproterenol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.Minor (1)isoproterenol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• isradipine

  Monitor Closely (1)atenolol, isradipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• ivabradine

  Monitor Closely (1)ivabradine, atenolol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Most patients receiving ivabradine will also be treated with a beta-blocker. The risk of bradycardia increases with coadministration of drugs that slow heart rate (eg, digoxin, amiodarone, beta-blockers). Monitor heart rate in patients taking ivabradine with other negative chronotropes.

• juniper

  Monitor Closely (1)juniper, chlorthalidone. 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.

• ketamine

  Monitor Closely (1)ketamine, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• ketoprofen

  Monitor Closely (3)ketoprofen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketoprofen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and ketoprofen both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of ketoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac

  Monitor Closely (3)atenolol and ketorolac both increase serum potassium. Use Caution/Monitor.
  
  ketorolac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  ketorolac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of ketorolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac intranasal

  Monitor Closely (3)atenolol and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.
  
  ketorolac intranasal decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  ketorolac intranasal increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .Minor (1)chlorthalidone 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)chlorthalidone decreases levels of L-methylfolate by increasing renal clearance. Minor/Significance Unknown.

• labetalol

  Monitor Closely (2)atenolol and labetalol both increase serum potassium. Use Caution/Monitor.
  
  labetalol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and labetalol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• lasmiditan

  Monitor Closely (1)atenolol increases effects of lasmiditan by pharmacodynamic synergism. Use Caution/Monitor. Lasmiditan has been associated with a lowering of heart rate (HR). In a drug interaction study, addition of a single 200-mg dose of lasmiditan to propranolol decreased HR by an additional 5 bpm compared to propranolol alone, for a mean maximum of 19 bpm.

• levalbuterol

  Monitor Closely (3)levalbuterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of levalbuterol by pharmacodynamic antagonism. Use Caution/Monitor.Minor (1)levalbuterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• levobetaxolol

  Minor (1)levobetaxolol increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• levodopa

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

• lily of the valley

  Monitor Closely (1)chlorthalidone 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 (1)chlorthalidone 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

  Monitor Closely (1)chlorthalidone increases toxicity of lithium by decreasing elimination. Use Caution/Monitor.

• lofexidine

  Serious - Use Alternative (2)lofexidine, chlorthalidone. 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, atenolol. 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 (3)atenolol and lornoxicam both increase serum potassium. Use Caution/Monitor.
  
  lornoxicam increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  lornoxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of lornoxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• losartan

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

• lurasidone

  Monitor Closely (2)lurasidone increases effects of atenolol 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 chlorthalidone 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)chlorthalidone decreases levels of magnesium chloride by increasing renal clearance. Minor/Significance Unknown.

• magnesium citrate

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

• magnesium hydroxide

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

• magnesium oxide

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

• magnesium sulfate

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

• maitake

  Monitor Closely (1)maitake increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypokalemia (theoretical interaction).Minor (1)maitake increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• maraviroc

  Monitor Closely (2)maraviroc, chlorthalidone. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.
  
  maraviroc, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of orthostatic hypotension.

• meclofenamate

  Monitor Closely (3)atenolol and meclofenamate both increase serum potassium. Use Caution/Monitor.
  
  meclofenamate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  meclofenamate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of meclofenamate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefenamic acid

  Monitor Closely (3)mefenamic acid decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
  
  mefenamic acid increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefloquine

  Monitor Closely (1)mefloquine increases levels of atenolol by decreasing metabolism. Use Caution/Monitor. Risk of arrhythmia.

• melatonin

  Minor (1)melatonin decreases toxicity of atenolol by pharmacodynamic antagonism. Minor/Significance Unknown. Melatonin may correct beta blocker induced sleep disturbances.

• meloxicam

  Monitor Closely (3)meloxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  meloxicam increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and meloxicam both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mesalamine

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

• metaproterenol

  Monitor Closely (3)metaproterenol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of metaproterenol by pharmacodynamic antagonism. Use Caution/Monitor.Minor (1)metaproterenol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• metformin

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

• methoxsalen

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

• methyclothiazide

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

• methyl aminolevulinate

  Serious - Use Alternative (1)chlorthalidone, 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.

• methylprednisolone

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

• metipranolol ophthalmic

  Minor (1)metipranolol ophthalmic increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• metolazone

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

• metoprolol

  Monitor Closely (2)metoprolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and metoprolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and metoprolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• miglitol

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

• minoxidil

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

• mometasone inhaled

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

• moxisylyte

  Monitor Closely (1)moxisylyte and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• mycophenolate

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

• nabumetone

  Monitor Closely (3)nabumetone increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  nabumetone decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and nabumetone both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nadolol

  Monitor Closely (2)nadolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and nadolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and nadolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• naproxen

  Monitor Closely (3)atenolol and naproxen both increase serum potassium. Use Caution/Monitor.
  
  naproxen increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  naproxen decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nateglinide

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

• nebivolol

  Monitor Closely (2)nebivolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and nebivolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and nebivolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• neostigmine

  Minor (1)atenolol, neostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.

• nicardipine

  Monitor Closely (1)atenolol, nicardipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nifedipine

  Monitor Closely (1)atenolol, nifedipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nimodipine

  Monitor Closely (1)atenolol, nimodipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nisoldipine

  Monitor Closely (1)atenolol, nisoldipine. Either decreases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs lower blood pressure.

• nitazoxanide

  Monitor Closely (1)nitazoxanide, chlorthalidone. Either increases levels of the other by Mechanism: plasma protein binding competition. Use Caution/Monitor.

• nitroglycerin rectal

  Monitor Closely (2)nitroglycerin rectal, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Beta-blockers blunt the reflex tachycardia produced by nitroglycerin without preventing its hypotensive effects. If beta-blockers are used with nitroglycerin in patients with angina pectoris, additional hypotensive effects may occur.
  
  nitroglycerin rectal, chlorthalidone. 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 chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
  
  atenolol and noni juice both increase serum potassium. Minor/Significance Unknown.

• norepinephrine

  Monitor Closely (3)norepinephrine and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of norepinephrine by pharmacodynamic antagonism. Use Caution/Monitor.Minor (1)norepinephrine, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• octacosanol

  Minor (2)octacosanol increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.
  
  octacosanol increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.

• oliceridine

  Monitor Closely (1)oliceridine decreases effects of chlorthalidone 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 (3)atenolol, olmesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy.
  
  olmesartan increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  olmesartan and atenolol both increase serum potassium. Use Caution/Monitor.

• olodaterol inhaled

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

• ospemifene

  Monitor Closely (1)chlorthalidone, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely.

• oxaprozin

  Monitor Closely (3)atenolol and oxaprozin both increase serum potassium. Use Caution/Monitor.
  
  oxaprozin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  oxaprozin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• oxybutynin

  Minor (1)atenolol increases levels of oxybutynin by decreasing metabolism. Minor/Significance Unknown.

• oxybutynin topical

  Minor (1)atenolol increases levels of oxybutynin topical by decreasing metabolism. Minor/Significance Unknown.

• oxybutynin transdermal

  Minor (1)atenolol increases levels of oxybutynin transdermal by decreasing metabolism. Minor/Significance Unknown.

• oxymetazoline topical

  Monitor Closely (1)oxymetazoline topical increases and atenolol decreases sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• parecoxib

  Monitor Closely (3)parecoxib increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and parecoxib both increase serum potassium. Use Caution/Monitor.
  
  parecoxib decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• penbutolol

  Monitor Closely (2)penbutolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and penbutolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and penbutolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• pentobarbital

  Monitor Closely (1)pentobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of pentobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• phenobarbital

  Monitor Closely (1)phenobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of phenobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• phenoxybenzamine

  Monitor Closely (1)phenoxybenzamine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• phentolamine

  Monitor Closely (1)phentolamine and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• physostigmine

  Minor (1)atenolol, physostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.

• pilocarpine

  Minor (1)pilocarpine increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.

• pindolol

  Monitor Closely (2)pindolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and pindolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and pindolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• pioglitazone

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

• pirbuterol

  Monitor Closely (3)atenolol decreases effects of pirbuterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and pirbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  pirbuterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.Minor (1)pirbuterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• piroxicam

  Monitor Closely (3)piroxicam increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  piroxicam decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and piroxicam both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone 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, chlorthalidone. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ponesimod

  Monitor Closely (1)ponesimod and atenolol both increase pharmacodynamic synergism. Use Caution/Monitor. Beta-blockers may have additive effects on lowering HR. Consider resting HR before initiating ponesimod in patients on stable dose of beta-blocker. Refer to the ponesimod prescribing information for more dosing information.

• porfimer

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

• potassium acid phosphate

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

• potassium chloride

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

• potassium citrate

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

• prazosin

  Monitor Closely (1)prazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• prednisolone

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

• prednisone

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

• primidone

  Monitor Closely (1)primidone decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of primidone. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• probenecid

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

• propofol

  Monitor Closely (1)propofol, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• propranolol

  Monitor Closely (2)atenolol and propranolol both increase serum potassium. Use Caution/Monitor.
  
  propranolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and propranolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• reishi

  Minor (2)reishi increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.
  
  reishi increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.

• repaglinide

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

• rivastigmine

  Serious - Use Alternative (1)atenolol increases toxicity of rivastigmine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive bradycardia effect may result in syncope.

• rose hips

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

• rosiglitazone

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

• sacubitril/valsartan

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

• salicylates (non-asa)

  Monitor Closely (3)salicylates (non-asa) decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  salicylates (non-asa) increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone 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 (3)salmeterol and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol decreases effects of salmeterol by pharmacodynamic antagonism. Use Caution/Monitor.
  
  atenolol increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)salmeterol, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• salsalate

  Monitor Closely (3)salsalate increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  salsalate decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and salsalate both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of salsalate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• saquinavir

  Serious - Use Alternative (1)saquinavir, atenolol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased risk of PR prolongation and cardiac arrhythmias.

• saxagliptin

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

• secobarbital

  Monitor Closely (1)secobarbital decreases levels of atenolol by increasing metabolism. Use Caution/Monitor. Consider a higher beta-blocker dose during coadministration of secobarbital. Atenolol, sotalol, nadolol less likely to be affected than other beta blockers.

• sevoflurane

  Monitor Closely (1)sevoflurane, atenolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.

• shark cartilage

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

• shepherd's purse

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

• sildenafil

  Monitor Closely (1)atenolol increases effects of sildenafil by additive vasodilation. Use Caution/Monitor. Sildenafil has systemic vasodilatory properties and may further lower blood pressure in patients taking antihypertensive medications. Monitor blood pressure response to sildenafil in patients receiving concurrent blood pressure lowering therapy.

• silodosin

  Monitor Closely (1)silodosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• siponimod

  Monitor Closely (1)siponimod, atenolol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Caution when siponimod is initiated in patients receiving beta-blocker treatment because of additive effects on lowering heart rate. Temporary interruption of beta-blocker may be needed before initiating siponimod. Beta-blocker treatment can be initiated in patients receiving stable doses of siponimod.

• sitagliptin

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

• sodium bicarbonate

  Monitor Closely (1)sodium bicarbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium citrate/citric acid

  Monitor Closely (1)sodium citrate/citric acid decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (1)sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of chlorthalidone 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 (1)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of chlorthalidone 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)chlorthalidone and sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol both decrease serum potassium. Modify Therapy/Monitor Closely.

• sotalol

  Monitor Closely (2)atenolol and sotalol both increase serum potassium. Use Caution/Monitor.
  
  sotalol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and sotalol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• spironolactone

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

• squill

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

• succinylcholine

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

• sulfadiazine

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

• sulfamethoxazole

  Minor (2)chlorthalidone increases levels of sulfamethoxazole by unspecified interaction mechanism. Minor/Significance Unknown.
  
  chlorthalidone, sulfamethoxazole. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• sulfasalazine

  Monitor Closely (3)atenolol and sulfasalazine both increase serum potassium. Use Caution/Monitor.
  
  sulfasalazine increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sulfasalazine decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• sulfisoxazole

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

• sulindac

  Monitor Closely (3)atenolol and sulindac both increase serum potassium. Use Caution/Monitor.
  
  sulindac increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  sulindac decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.Minor (1)chlorthalidone will increase the level or effect of sulindac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tadalafil

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

• telmisartan

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

• temocillin

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

• terazosin

  Monitor Closely (1)terazosin and atenolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.

• terbutaline

  Monitor Closely (3)atenolol increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol decreases effects of terbutaline by pharmacodynamic antagonism. Use Caution/Monitor.
  
  terbutaline and chlorthalidone both decrease serum potassium. Use Caution/Monitor.Minor (2)chlorthalidone, terbutaline. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive hypokalemic effects.
  
  terbutaline, chlorthalidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Hypokalemia.

• theophylline

  Monitor Closely (1)atenolol, theophylline. Other (see comment). Use Caution/Monitor. Comment: Beta blockers (esp. non selective) antagonize theophylline effects, while at the same time increasing theophylline levels and toxicity (mechanism: decreased theophylline metabolism). Smoking increases risk of interaction.

• ticarcillin

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

• timolol

  Monitor Closely (2)timolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  atenolol and timolol both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)atenolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.

• tizanidine

  Minor (2)tizanidine increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.
  
  tizanidine increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.

• tolazamide

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

• tolbutamide

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

• tolfenamic acid

  Monitor Closely (3)tolfenamic acid increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  tolfenamic acid decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and tolfenamic acid both increase serum potassium. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of tolfenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolmetin

  Monitor Closely (3)tolmetin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and tolmetin both increase serum potassium. Use Caution/Monitor.
  
  tolmetin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of tolmetin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolvaptan

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

• toremifene

  Monitor Closely (1)chlorthalidone, 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)torsemide and chlorthalidone both decrease serum potassium. Use Caution/Monitor.
  
  atenolol increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• treprostinil

  Minor (2)treprostinil increases effects of atenolol by pharmacodynamic synergism. Minor/Significance Unknown.
  
  treprostinil increases effects of chlorthalidone by pharmacodynamic synergism. Minor/Significance Unknown.

• tretinoin

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

• tretinoin topical

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

• triamcinolone acetonide injectable suspension

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

• triamterene

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

• trientine

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

• trilostane

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

• trimethoprim

  Minor (1)chlorthalidone, trimethoprim. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Risk of hyponatremia.

• umeclidinium bromide/vilanterol inhaled

  Monitor Closely (1)umeclidinium bromide/vilanterol inhaled and chlorthalidone 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)chlorthalidone will increase the level or effect of valganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• valsartan

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

• verapamil

  Monitor Closely (1)atenolol and verapamil both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)verapamil, atenolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.

• verteporfin

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

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (1)vilanterol/fluticasone furoate inhaled and chlorthalidone 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)chlorthalidone decreases effects of vildagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Thiazide dosage >50 mg/day may increase blood glucose.

• vitamin D

  Monitor Closely (1)chlorthalidone 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.

• willow bark

  Minor (1)chlorthalidone 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 atenolol by pharmacodynamic synergism. Use Caution/Monitor.
  
  xipamide increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor.

• yohimbe

  Minor (1)atenolol decreases toxicity of yohimbe by pharmacodynamic antagonism. Minor/Significance Unknown.