Patient Education


Generic name

Dorzolamide hydrochloride and timolol maleate


Cosopt is a combination drug of 2% Trusopt® and 0.5% timolol.

Mechanism of action

This is a combination drug with a carbonic anhydrase inhibitor (dorzolamide) and a beta blocker (timolol). Dorzolamide helps reduce pressure within the eye (intraocular pressure) by decreasing fluid (aqueous humor) production. Timolol lowers intraocular pressure by decreasing aqueous humor production and increasing drainage.


Treatment of open angle glaucoma and ocular hypertension.


Instill one drop of Cosopt ophthalmic solution into the affected eye(s) two times daily.

Use with caution in patients with/during:
  1. Timolol should NOT be used in patients with preexisting cardiac disease, such as severe bradycardia, advanced AV block, cardiogenic shock, coronary artery disease, vasospastic angina, or congestive heart failure, particularly those with severe left ventricular dysfunction.
  2. Asthma or pulmonary disease (COPD, emphysema, bronchitis)
  3. Diabetes mellitis because it can mask symptoms of hypoglycemia
  4. Hyperthyroidism because it may mask tachycardia
  5. Using an oral beta blocker
  6. Renal impairment or severe renal disease (with a creatinine clearance less than 30 milliliters per minute)
  7. Hepatic disease
  8. Raynaud's disease or peripheral vascular disease
  9. Myasthenia gravis
  10. Sulfonamide hypersensitivity
  11. Psoriasis
  12. Pregnancy, breastfeeding, or in children
Common Side Effects
  • Eye itching
  • Taste changes
  • Ocular burning and/or stinging
  • Blurred vision
Life-Threatening Symptoms
  • Chest pain
  • Angioedema (swelling of the lips, eyes, or tongue)
  • Difficulty breathing
Less Common to Rare Side Effects
  • Dizziness
  • Nausea
  • Stomach or back pain
  • Upper respiratory infection
  • Cloudy vision
  • Headache
  • Eyelid edema (swelling of the eyelids due to fluid accumulation)
  • Conjunctivitis (inflammation of the conjunctiva)
  • Hypertension (high blood pressure)
  • Dry eyes
  • Cough
  • Conjunctival edema (swelling of the conjunctiva due to fluid accumulation)
  • Corneal erosion or staining
  • Upset stomach
  • Eye pain, tearing, or discharge
  • Increased bleeding

Dorzolamide is a sulfonamide and has may cause a severe allergic reaction in patients with a sulfa drug allergy.