COSOPT (dorzolamide hydrochloride-timolol maleate ophthalmic solution) is the combination of a topical carbonic anhydrase inhibitor and a topical beta-adrenergic receptor blocking agent.

Dorzolamide hydrochloride is described chemically as: (4S-trans)-4-(ethylamino)-5,6-dihydro-6-methyl-4H-thieno[2,3-b]thiopyran-2-sulfonamide 7,7-dioxide monohydrochloride. Dorzolamide hydrochloride is optically active. The specific rotation is:

? 25° (C=1, water) = ~ -17°.
405 nm

Its empirical formula is C₁₀H₁₆N₂O₄S₃•HCl and its structural formula is:

Dorzolamide hydrochloride has a molecular weight of 360.91. It is a white to off-white, crystalline powder, which is soluble in water and slightly soluble in methanol and ethanol.

Timolol maleate is described chemically as: (-)-1-(tert-butylamino)-3-[(4-morpholino-1,2,5-thiadiazol-3-yl)oxy]-2-propanol maleate (1:1) (salt). Timolol maleate possesses an asymmetric carbon atom in its structure and is provided as the levo-isomer. The optical rotation of timolol maleate is:

[?] 25°C in 1N HCl (C = 5) = -12.2° (?­11.7° to -12.5°).
405 nm

Its molecular formula is C₁₃H₂₄N₄O₃S•C₄H₄O₄ and its structural formula is:

Timolol maleate has a molecular weight of 432.50. It is a white, odorless, crystalline powder which is soluble in water, methanol, and alcohol. Timolol maleate is stable at room temperature.

COSOPT (dorzolamide hydrochloride-timolol maleate ophthalmic solution) is supplied as a sterile, isotonic, buffered, slightly viscous, aqueous solution. The pH of the solution is approximately 5.65, and the osmolarity is 242-323 mOsM. Each mL of COSOPT (dorzolamide hydrochloride-timolol maleate ophthalmic solution) contains 20 mg dorzolamide (22.26 mg of dorzolamide hydrochloride) and 5 mg timolol (6.83 mg timolol maleate). Inactive ingredients are sodium citrate, hydroxyethyl cellulose, sodium hydroxide, mannitol, and water for injection. Benzalkonium chloride 0.0075% is added as a preservative.

SIDE EFFECTS: Temporary blurred vision, temporary burning/stinging/itching/redness of the eye, watery eyes, dry eyes, feeling as if something is in the eye, sensitivity of eyes to light, strange taste in the mouth, headache, dizziness, or drowsiness may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: slow/irregular heartbeat, muscle weakness, mental/mood changes, coldness/numbness/pain in the hands or feet.

Tell your doctor immediately if any of these rare but very serious side effects occur: vision changes, signs of a kidney stone (e.g., pain in the back/side/abdomen, nausea/vomiting, blood in the urine), yellowing eyes or skin, dark urine, unusual tiredness/weakness, easy bruising/bleeding, signs of infection (e.g., fever, chills, persistent sore throat).

Seek immediate medical attention if any of these rare but very serious side effects occur: persistent eye redness or discharge, eye or eyelid swelling, eye pain, trouble breathing, sudden unexplained weight gain, chest pain, weakness on one side of the body, slurred speech, confusion, persistent dizziness, fainting.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using timolol/dorzolamide, tell your doctor or pharmacist if you are allergic to these drugs; or if you have any other allergies. This product may contain inactive ingredients (such as preservatives like benzalkonium chloride), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: lung disease (e.g., current or past history of asthma, severe chronic obstructive pulmonary disease), certain types of irregular heartbeats (e.g., sinus bradycardia, second or third degree AV block), certain types of heart disease (e.g., severe heart failure).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, kidney stones, liver disease, diabetes, overactive thyroid disease, muscle weakness disorders, low blood flow to the brain (cerebrovascular insufficiency), severe allergies.

If you develop an eye infection or injury, or have eye surgery, check with your doctor about whether you should continue to use your current bottle of timolol/dorzolamide. You may be advised to start using a new bottle.

Before having surgery, tell your doctor or dentist that you are using this medication.

This drug may make you dizzy or drowsy or cause temporary blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breast-feeding.