Generic drug: dorzolamide hydrochloride-timolol maleate

Brand name: Cosopt

What is Cosopt (dorzolamide hydrochloride-timolol maleate), and how does it work?

Cosopt (dorzolamide hydrochloride-timolol maleate) is a prescription eye drop solution that contains two medicines, dorzolamide hydrochloride called an ophthalmic carbonic anhydrase inhibitor and timolol maleate called a beta-blocker.

Cosopt is used to lower high pressure in the eye in people with open-angle glaucoma or ocular hypertension when a beta-blocking medicine alone does not work to control the eye pressure. It is not known if Cosopt is safe and effective in children 2 years of age and younger.

What are the side effects of Cosopt?

Cosopt may cause serious side effects, including:

  • severe breathing problems. These breathing problems can happen in people who have asthma, chronic obstructive pulmonary disease, or heart failure and can cause death. Tell your healthcare provider right away if you have breathing problems while using Cosopt.
  • heart failure. This can happen in people who already have heart failure and in people who have never had heart failure before. Tell your healthcare provider right away if you get any of these symptoms of heart failure while taking Cosopt:
  • serious sulfa (sulfonamide) reactions. Serious reactions including death can happen in people who are allergic to sulfonamide medicines like one of the medicines in Cosopt. Other serious reactions can include:
    • severe skin reactions
    • liver problems
    • blood problems
  • Stop using Cosopt and call your healthcare provider or get emergency help right away if you get any of these symptoms of an allergic reaction:
  • increased allergic reactions. People who have a genetic history of developing allergies (atopy) or who have a history of severe anaphylactic reactions from different allergens may have increased allergic reactions while taking beta-blockers, like one of the medicines in Cosopt. Your usual dose of epinephrine used to treat your anaphylactic reactions may not work as well. Stop using Cosopt and call your healthcare provider or get emergency help right away if you get any of these symptoms of an allergic reaction:
    • swelling of your face, lips, mouth, or tongue
    • trouble breathing
    • wheezing
    • severe itching
    • skin rash, redness, or swelling
    • dizziness or fainting
    • fast heartbeat or pounding in your chest
    • sweating
  • worsening muscle weakness. Muscle weakness symptoms including double vision or drooping eyelids can happen while using Cosopt. Muscle weakness can get worse in people who already have problems with muscle weakness like myasthenia gravis.
  • swelling of eye. Some people with low counts of certain types of cells in the eye have developed corneal edema when using Cosopt. Call your healthcare provider if you have swelling in your eyes.

The most common side effects of Cosopt include:

  • eye burning
  • eye stinging
  • eye redness
  • blurred vision
  • eye tearing
  • eye itching
  • a bitter, sour, or unusual taste after putting in your eyedrops

These are not all the possible side effects of Cosopt.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA1088

What is the dosage for Cosopt?

  • The dose is one drop of Cosopt in the affected eye(s) two times daily.
  • If more than one topical ophthalmic drug is being used, the drugs should be administered at least five minutes apart

What drugs interact with Cosopt?

Oral Carbonic Anhydrase Inhibitors

  • There is a potential for an additive effect on the known systemic effects of carbonic anhydrase inhibition in patients receiving an oral carbonic anhydrase inhibitor and Cosopt.
  • The concomitant administration of Cosopt and oral carbonic anhydrase inhibitors is not recommended.

High-Dose Salicylate Therapy

  • Although acid-base and electrolyte disturbances were not reported in the clinical trials with dorzolamide hydrochloride ophthalmic solution, these disturbances have been reported with oral carbonic anhydrase inhibitors and have, in some instances, resulted in drug interactions (e.g., toxicity associated with high-dose salicylate therapy). Therefore, the potential for such drug interactions should be considered in patients receiving Cosopt.

Beta-Adrenergic Blocking Agents

  • Patients who are receiving a beta-adrenergic blocking agent orally and Cosopt should be observed for potential additive effects of beta-blockade, both systemic and on intraocular pressure.
  • The concomitant use of two topical beta-adrenergic blocking agents is not recommended.

Calcium Antagonists

  • Caution should be used in the coadministration of beta-adrenergic blocking agents, such as Cosopt, and oral or intravenous calcium antagonists because of possible atrioventricular conduction disturbances, left ventricular failure, and hypotension. In patients with impaired cardiac function, coadministration should be avoided.

Catecholamine-Depleting Drugs

  • Close observation of the patient is recommended when a beta-blocker is administered to patients receiving catecholamine-depleting drugs, such as reserpine, because of possible additive effects and the production of hypotension and/or marked bradycardia, which may result in vertigo, syncope, or postural hypotension.

Digitalis And Calcium Antagonists

  • The concomitant use of beta-adrenergic blocking agents with digitalis and calcium antagonists may have additive effects in prolonging atrioventricular conduction time.

CYP2D6 Inhibitors

  • Potentiated systemic beta-blockade (e.g., decreased heart rate, depression) has been reported during combined treatment with CYP2D6 inhibitors (e.g., quinidine, SSRIs) and timolol.

Clonidine

  • Oral beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. There have been no reports of exacerbation of rebound hypertension with ophthalmic timolol maleate.

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Is Cosopt safe to use while pregnant or breastfeeding?

  • There are no adequate and well-controlled studies in pregnant women. Cosopt should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
  • It is not known whether dorzolamide is excreted in human milk.
  • Timolol maleate has been detected in human milk following oral and ophthalmic drug administration.
  • Because of the potential for serious adverse reactions from Cosopt in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Summary

Cosopt (dorzolamide hydrochloride-timolol maleate) is a prescription eye drop solution that contains two medicines, dorzolamide hydrochloride called an ophthalmic carbonic anhydrase inhibitor and timolol maleate called a beta-blocker. Cosopt is used to lower high pressure in the eye in people with open-angle glaucoma or ocular hypertension when a beta-blocking medicine alone does not work to control the eye pressure. Serious side effects of Cosopt include severe breathing problems, heart failure, and serious sulfa (sulfonamide) reactions.

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Medically Reviewed on 3/18/2021
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All sections courtesy of the U.S. Food and Drug Administration