Dosing & Uses
Dosage Forms & Strengths
timolol/dorzolamide
ophthalmic solution
- 0.5%/2%
Open-Angle Glaucoma or Ocular Hypertension
Instill 1 gtt in affected eye(s) q12hr
Dosage Forms & Strengths
timolol/dorzolamide
ophthalmic solution
- 0.5%/2%
Open-Angle Glaucoma or Ocular Hypertension
<2 years
- Contraindicated
>2 years
- Instill 1 gtt in affected eye(s) q12hr
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (34)
- acebutolol
acebutolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- artemether/lumefantrine
artemether/lumefantrine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- atenolol
atenolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- betaxolol
betaxolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- bisoprolol
bisoprolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- carvedilol
carvedilol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- celiprolol
celiprolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- clonidine
clonidine, timolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.
- dacomitinib
dacomitinib will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.
- digoxin
digoxin, timolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.
- diltiazem
diltiazem, timolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.
- epinephrine
timolol increases effects of epinephrine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of hypertension and bradycardia. Consider selective beta 1 blocker (e.g., metoprolol).
- epinephrine racemic
timolol increases effects of epinephrine racemic by pharmacodynamic synergism. Avoid or Use Alternate Drug. Risk of hypertension and bradycardia. Consider selective beta 1 blocker (e.g., metoprolol).
- esmolol
esmolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- fexinidazole
fexinidazole, timolol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to induce bradycardia. .
- fluoxetine
fluoxetine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- givosiran
givosiran will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.
- iobenguane I 131
timolol will decrease the level or effect of iobenguane I 131 by Other (see comment). Avoid or Use Alternate Drug. Based on the mechanism of action of iobenguane, drugs that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells, and thus, reduce iobenguane efficacy. Discontinue interfering drugs for at least 5 half-lives before administration of either the dosimetry or an iobenguane dose. Do not administer these drugs until at least 7 days after each iobenguane dose.
- labetalol
labetalol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- lofexidine
lofexidine, timolol. 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.
- lumefantrine
lumefantrine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- metoprolol
metoprolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- nadolol
nadolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- nebivolol
nebivolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- paroxetine
paroxetine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- penbutolol
penbutolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- pindolol
pindolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- propranolol
propranolol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- quinidine
quinidine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- rivastigmine
timolol increases toxicity of rivastigmine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive bradycardia effect may result in syncope.
- sotalol
sotalol and timolol both increase anti-hypertensive channel blocking. Avoid or Use Alternate Drug.
- umeclidinium bromide/vilanterol inhaled
timolol, umeclidinium bromide/vilanterol inhaled. pharmacodynamic antagonism. Avoid or Use Alternate Drug. If a beta-blocker must be used in patients with COPD taking a beta-agonist, consider using a beta-blocker that is beta-1 selective .
- verapamil
verapamil, timolol. Either increases toxicity of the other by unspecified interaction mechanism. Avoid or Use Alternate Drug. Can increase risk of bradycardia.
- vilanterol/fluticasone furoate inhaled
timolol, vilanterol/fluticasone furoate inhaled. pharmacodynamic antagonism. Avoid or Use Alternate Drug. If a beta-blocker must be used in patients with COPD taking a beta-agonist, consider using a beta-blocker that is beta-1 selective .
Monitor Closely (131)
- acebutolol
acebutolol and timolol both increase serum potassium. Use Caution/Monitor.
- aceclofenac
timolol and aceclofenac both increase serum potassium. Use Caution/Monitor.
aceclofenac decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - acemetacin
timolol and acemetacin both increase serum potassium. Use Caution/Monitor.
acemetacin decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - albuterol
timolol increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of albuterol by pharmacodynamic antagonism. Use Caution/Monitor. - aldesleukin
aldesleukin increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
- alfuzosin
alfuzosin and timolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- aluminum hydroxide
aluminum hydroxide decreases levels of timolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.
- amantadine
dorzolamide will decrease the level or effect of amantadine by Other (see comment). Modify Therapy/Monitor Closely. Excretion rate of amantadine increases rapidly when urine is acidic, administration of urine acidifying drugs may increase elimination of amantadine from the body. Monitor for efficacy of amantadine.
- amifostine
amifostine, timolol. 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
timolol and amiloride both increase serum potassium. Modify Therapy/Monitor Closely.
- amiodarone
amiodarone will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
amiodarone, timolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of cardiotoxicity with bradycardia. - amlodipine
timolol and amlodipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- amobarbital
amobarbital decreases levels of timolol 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
timolol increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of arformoterol by pharmacodynamic antagonism. Use Caution/Monitor. - articaine
timolol, articaine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Increased effects of epinephrine in anesthetic; risk of hypertension and bradycardia. Do NOT D/C chronic beta blocker Tx prior to anesthetic administration. Consider selective beta 1 blocker (e.g., metoprolol).
- asenapine
asenapine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
asenapine and timolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely. - aspirin
timolol and aspirin both increase serum potassium. Use Caution/Monitor.
aspirin decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - aspirin rectal
timolol and aspirin rectal both increase serum potassium. Use Caution/Monitor.
aspirin rectal decreases effects of timolol 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 timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
timolol and aspirin/citric acid/sodium bicarbonate both increase serum potassium. Use Caution/Monitor. - atazanavir
atazanavir increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of hypotension, bradycardia, AV block, and prolonged PR interval. Consider lowering beta blocker dose.
- atenolol
atenolol and timolol both increase serum potassium. Use Caution/Monitor.
- avanafil
avanafil increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
- bendroflumethiazide
timolol increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- betaxolol
betaxolol and timolol both increase serum potassium. Use Caution/Monitor.
- bismuth subsalicylate
bismuth subsalicylate, timolol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Blockage of renal prostaglandin synthesis; may cause severe hypertension.
- bisoprolol
bisoprolol and timolol both increase serum potassium. Use Caution/Monitor.
- bretylium
timolol, bretylium. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Each drug may cause hypotension.
- bumetanide
timolol increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- bupivacaine
timolol, bupivacaine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Use extreme caution during concomitant use of bupivacaine and antihypertensive agents.
- bupropion
bupropion will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- butabarbital
butabarbital decreases levels of timolol 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 timolol 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.
- calcium acetate
calcium acetate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
- calcium carbonate
calcium carbonate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
calcium carbonate decreases levels of timolol 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 timolol by unspecified interaction mechanism. Use Caution/Monitor.
- calcium citrate
calcium citrate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
- calcium gluconate
calcium gluconate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
- candesartan
candesartan and timolol both increase serum potassium. Use Caution/Monitor.
timolol, candesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy. - carbenoxolone
timolol increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carbidopa
carbidopa increases effects of timolol 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 and timolol both increase serum potassium. Use Caution/Monitor.
- celecoxib
celecoxib will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
timolol and celecoxib both increase serum potassium. Use Caution/Monitor.
celecoxib decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - celiprolol
celiprolol and timolol both increase serum potassium. Use Caution/Monitor.
- chloroprocaine
timolol, chloroprocaine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Increased effects of epinephrine in anesthetic; risk of hypertension and bradycardia. Do NOT D/C chronic beta blocker Tx prior to anesthetic administration. Consider selective beta 1 blocker (e.g., metoprolol).
- chloroquine
chloroquine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- chlorothiazide
timolol increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpropamide
timolol decreases effects of chlorpropamide by pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers may also mask the symptoms of hypoglycemia.
- chlorthalidone
timolol increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- choline magnesium trisalicylate
timolol and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.
choline magnesium trisalicylate decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - cimetidine
cimetidine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- citalopram
citalopram increases levels of timolol by decreasing metabolism. Use Caution/Monitor.
- clevidipine
timolol and clevidipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- clonidine
timolol, clonidine. Mechanism: pharmacodynamic synergism. Modify Therapy/Monitor Closely. Non selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.
- cobicistat
cobicistat will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- cyclopenthiazide
timolol increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- darifenacin
darifenacin will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- dasiglucagon
timolol 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.
- desflurane
desflurane, timolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
- desvenlafaxine
desvenlafaxine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg
- diclofenac
timolol and diclofenac both increase serum potassium. Use Caution/Monitor.
diclofenac decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - diflunisal
timolol and diflunisal both increase serum potassium. Use Caution/Monitor.
diflunisal decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - digoxin
timolol and digoxin both increase serum potassium. Use Caution/Monitor.
timolol increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor. Enhanced bradycardia. - diltiazem
timolol and diltiazem both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- diphenhydramine
diphenhydramine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- dobutamine
timolol increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of dobutamine by pharmacodynamic antagonism. Use Caution/Monitor. - dopexamine
timolol increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of dopexamine by pharmacodynamic antagonism. Use Caution/Monitor. - doxazosin
doxazosin and timolol both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- dronedarone
dronedarone will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- drospirenone
timolol and drospirenone both increase serum potassium. Modify Therapy/Monitor Closely.
- duloxetine
duloxetine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- eliglustat
eliglustat increases levels of timolol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of timolol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
- ephedrine
timolol increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of ephedrine by pharmacodynamic antagonism. Use Caution/Monitor. - epinephrine
timolol increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. - epinephrine inhaled
timolol decreases effects of epinephrine inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Beta2-adrenergic blockers may may inhibit bronchodilatory effects of epinephrine.
- epinephrine racemic
timolol increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. - eprosartan
eprosartan and timolol both increase serum potassium. Use Caution/Monitor.
timolol, eprosartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy. - esmolol
esmolol and timolol both increase serum potassium. Use Caution/Monitor.
- ethacrynic acid
timolol increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ether
timolol, 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
timolol and etodolac both increase serum potassium. Use Caution/Monitor.
etodolac decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - etomidate
etomidate, timolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
- fedratinib
fedratinib will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.
- felodipine
timolol and felodipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- fenbufen
timolol and fenbufen both increase serum potassium. Use Caution/Monitor.
- fenoprofen
timolol and fenoprofen both increase serum potassium. Use Caution/Monitor.
fenoprofen decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - fingolimod
timolol 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.
- flurbiprofen
timolol and flurbiprofen both increase serum potassium. Use Caution/Monitor.
flurbiprofen decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - formoterol
timolol increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of formoterol by pharmacodynamic antagonism. Use Caution/Monitor. - furosemide
timolol increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- gentamicin
timolol increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- glimepiride
timolol decreases effects of glimepiride by pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers may also mask the symptoms of hypoglycemia.
- glipizide
timolol decreases effects of glipizide by pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers may also mask the symptoms of hypoglycemia.
- glucagon
glucagon decreases toxicity of timolol 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
glucagon intranasal decreases toxicity of timolol 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
timolol decreases effects of glyburide by pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers may also mask the symptoms of hypoglycemia.
- guanfacine
timolol, guanfacine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Non selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.
- haloperidol
haloperidol will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- hydralazine
hydralazine increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects.
- hydrochlorothiazide
timolol increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ibuprofen
timolol and ibuprofen both increase serum potassium. Use Caution/Monitor.
ibuprofen decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - ibuprofen IV
ibuprofen IV decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
timolol and ibuprofen IV both increase serum potassium. Use Caution/Monitor. - imatinib
imatinib will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- indacaterol, inhaled
indacaterol, inhaled, timolol. 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.
- indapamide
timolol increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- indomethacin
timolol and indomethacin both increase serum potassium. Use Caution/Monitor.
indomethacin decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - insulin aspart
timolol, insulin aspart. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin degludec
timolol, 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
timolol, 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
timolol, insulin detemir. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin glargine
timolol, insulin glargine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin glulisine
timolol, insulin glulisine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin inhaled
timolol, 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
timolol, insulin lispro. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin NPH
timolol, insulin NPH. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- insulin regular human
timolol, insulin regular human. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Non selective beta blockers delay recovery of normoglycemia after insulin induced hypoglycemia; however, they also inhibit insulin secretion, so long term beta blocker Tx may result in reduced glucose tolerance. Insulin induced hypoglycemia may induce hypertension during non selective beta blocker Tx.
- irbesartan
irbesartan and timolol both increase serum potassium. Use Caution/Monitor.
timolol, irbesartan. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Risk of fetal compromise if given during pregnancy. - isoproterenol
timolol increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of isoproterenol by pharmacodynamic antagonism. Use Caution/Monitor. - isradipine
timolol and isradipine both increase anti-hypertensive channel blocking. Modify Therapy/Monitor Closely.
- ivabradine
ivabradine, timolol. 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, timolol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.
- ketoprofen
timolol and ketoprofen both increase serum potassium. Use Caution/Monitor.
ketoprofen decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - ketorolac
timolol and ketorolac both increase serum potassium. Use Caution/Monitor.
ketorolac decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - ketorolac intranasal
timolol and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.
ketorolac intranasal decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - labetalol
labetalol and timolol both increase serum potassium. Use Caution/Monitor.
- lasmiditan
timolol 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
timolol increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
timolol decreases effects of levalbuterol by pharmacodynamic antagonism. Use Caution/Monitor. - levodopa
levodopa increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
- lidocaine
timolol, lidocaine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Increased effects of epinephrine in anesthetic; risk of hypertension and bradycardia. Do NOT D/C chronic beta blocker Tx prior to anesthetic administration. Consider selective beta 1 blocker (e.g., metoprolol).
timolol increases levels of lidocaine by decreasing elimination. Use Caution/Monitor. Risk of hypertension and bradycardia. Consider selective beta 1 blocker (e.g., metoprolol). - lisdexamfetamine
dorzolamide will increase the level or effect of lisdexamfetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.
- lopinavir
lopinavir increases levels of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of PR prolongation and cardiac arrhythmias. .
Minor (28)
- adenosine
timolol, adenosine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Bradycardia.
- agrimony
agrimony increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- brimonidine
brimonidine increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- cevimeline
cevimeline increases effects of timolol by unspecified interaction mechanism. Minor/Significance Unknown.
- ciprofloxacin
ciprofloxacin increases levels of timolol by decreasing metabolism. Minor/Significance Unknown. May also rarely decrease beta blocker levels.
- cocaine
timolol increases effects of cocaine by pharmacodynamic synergism. Minor/Significance Unknown. Risk of angina.
- cornsilk
cornsilk increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- dihydroergotamine
dihydroergotamine, timolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.
- dihydroergotamine intranasal
dihydroergotamine intranasal, timolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Additive vasospasm.
- dipyridamole
dipyridamole, timolol. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of bradycardia.
- escitalopram
escitalopram increases levels of timolol by decreasing metabolism. Minor/Significance Unknown.
- fenoldopam
fenoldopam increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.
- forskolin
forskolin increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- imaging agents (gadolinium)
timolol, imaging agents (gadolinium). Mechanism: unknown. Minor/Significance Unknown. Increased risk of anaphylaxis from contrast media.
- levobetaxolol
levobetaxolol increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- maitake
maitake increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- melatonin
melatonin decreases toxicity of timolol by pharmacodynamic antagonism. Minor/Significance Unknown. Melatonin may correct beta blocker induced sleep disturbances.
- metipranolol ophthalmic
metipranolol ophthalmic increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- neostigmine
timolol, neostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.
- noni juice
timolol and noni juice both increase serum potassium. Minor/Significance Unknown.
- octacosanol
octacosanol increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- physostigmine
timolol, physostigmine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive bradycardia.
- pilocarpine
pilocarpine increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- reishi
reishi increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- shepherd's purse
shepherd's purse, timolol. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.
- tizanidine
tizanidine increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.
- treprostinil
treprostinil increases effects of timolol by pharmacodynamic synergism. Minor/Significance Unknown.
- yohimbe
timolol decreases toxicity of yohimbe by pharmacodynamic antagonism. Minor/Significance Unknown.
Adverse Effects
>10%
Dorzolamide
- Ocular burning, stinging, discomfort (33%)
- Bitter taste (25%)
- Superficial punctate keratitis (10-15%)
- Ocular allergic reactions (10%)
Frequency Not Defined
Dorzolamide
- Blurred vision
- Ocular dryness
- Photophobia
- Ocular redness
- Tearing
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
Timolol
- Arrythmia
- Bradycardia
- Syncope
- Fatigue
- Headache
- Dyspnea
- Bronchospasm
- Chest pain
- Edema
- Paresthesia
- Nausea
- Rales
- Depression
- Decreased exercise tolerance
- Raynaud's phenomenon
Warnings
Contraindications
Age <2 years
Hypersensitivity, asthma, severe COPD, sinus bradycardia, 2nd/3rd degree AV block (except in patients with artificial pacemaker), overt cardiac failure, cardiogenic shock
Cautions
Dorzolamide (a sulfonamide) and, although administered topically, is absorbed systemically; same types of adverse reactions attributable to sulfonamides may occur with topical administration, including severe skin reactions; severe respiratory reactions, including death due to bronchospasm in patients with asthma, and rarely death in association with cardiac failure, reported following systemic or ophthalmic administration of timolol maleate
Hypersensitivity may occur; fatalities have occurred, although rarely, due to severe reactions to sulfonamides including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias; sensitization may recur when a sulfonamide is readministered irrespective of route of administration; if signs of serious reactions or hypersensitivity occur, discontinue use of this preparation
Bacterial keratitis associated with use of multiple-dose containers of topical ophthalmic products, inadvertently contaminated by patients who, in most cases, had concurrent corneal disease or disruption of ocular epithelial surface
Conjunctivitis reported with chronic administration (may resolve upon discontinuation of therapy)
Sympathetic stimulation may be essential for support of circulation in diminished myocardial contractility; its inhibition by beta-adrenergic receptor blockade may precipitate more severe failure; in patients without history of cardiac failure continued depression of myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure; discontinue therapy at first sign or symptom of cardiac failure
Not for use as monotherapy in angle-closure glaucoma
Use caution in diabetes, heart failure, psychiatric disease (may cause or exacerbate CNS depression), peripheral vascular disease
Not for administration to patients with chronic obstructive pulmonary disease (e.g., chronic bronchitis, emphysema) of mild or moderate severity, bronchospastic disease, or a history of bronchospastic disease (other than bronchial asthma or a history of bronchial asthma, in which timolol is contraindicated)
Patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions; patients with a history of atopy or a history of severe anaphylactic reactions to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens
Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (eg, diplopia, ptosis, and generalized weakness); timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms
Beta-adrenergic receptor blocking agents may mask signs and symptoms of acute hypoglycemia; administer with caution in patients subject to spontaneous hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents
Beta-adrenergic blocking agents may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism; manage carefully patients suspected of developing thyrotoxicosis to avoid abrupt withdrawal of beta-adrenergic blocking agents that might precipitate thyroid storm
Not studied in patients with severe renal impairment (CrCl <30 mL/min); not recommended; dorzolamide and its metabolite are excreted predominantly by kidney
Use with caution in hepatic impairment; not studed
There is increased potential for developing corneal edema in patients with low endothelial cell counts; use caution
Avoid concomitant administration with systemic beta-blockers or carbonic anhydrase inhibitors
Use caution in patients taking calcium channel blockers, cardiac glycosides, or inhaled anesthetic agents
Mediated reflexes during surgery
- Necessity or desirability of withdrawal of beta-adrenergic blocking agents prior to major surgery is controversial; beta-adrenergic receptor blockade impairs ability of the heart to respond to beta-adrenergically mediated reflex stimuli; this may augment risk of general anesthesia in surgical procedures
- Some patients receiving beta-adrenergic receptor blocking agents have experienced protracted severe hypotension during anesthesia; difficulty in restarting and maintaining heartbeat has also been reported; for these reasons, in patients undergoing elective surgery, some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents
- If necessary during surgery, effects of beta-adrenergic blocking agents may be reversed by sufficient doses of adrenergic agonists
Pregnancy & Lactation
Pregnancy Category: C
Lactation: Excreted in breast milk; not recommended
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Dorzolamide: Sulfonamide and carbonic anhydrase inhibitor; inhibition of carbonic anhydrase in ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport
Timolol: Nonselective beta-adrenergic receptor blocker; reduces IOP by reducing production of aqueous humor
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Formulary
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