Dorzolamide timolol eye drops are a prescription eye drop that combines two medicines:
- Dorzolamide — a carbonic anhydrase inhibitor
- Timolol — a nonselective beta-blocker
They work together to lower intraocular pressure by reducing the production of aqueous humor in the eye. They’re used for open-angle glaucoma or ocular hypertension.
Brand names and strengths
- Often sold as Cosopt: dorzolamide 2% + timolol maleate 0.5% per mL
- A preservative-free version is available in some places (Cosopt PF)
How to use
- Dose: typically 1 drop in the affected eye(s) twice daily (morning and evening). Your doctor’s instructions may differ.
- If you use more than one eye drop, space them by about 5–10 minutes.
- Administration tips:
- Wash hands before use.
- Tilt head back, gently pull down the lower eyelid to make a small pocket.
- Instill 1 drop, close the eye, and press gently on the inner corner of the eye for 1–2 minutes to reduce drainage.
- Avoid touching the dropper tip to your eye or any surface.
- If you wear contact lenses, remove lenses before using the drops and wait at least 15 minutes to reinsert (for products containing preservative benzalkonium chloride). If you’re using the preservative-free version, check the label for guidance.
- Storage: follow the label; keep the bottle tightly closed and at room temperature unless instructed otherwise.
Common side effects
- Local: burning, stinging, dry eyes, tearing, blurred vision, redness.
- Metallic or bitter taste may occur after blinking.
- Some people may have conjunctival irritation or itching.
Potential but less common/systemic effects
- Timolol (beta-blocker) can cause systemic effects such as slow heart rate (bradycardia), low blood pressure, dizziness, fatigue, or bronchospasm (especially in people with asthma or COPD). Rarely, it can interfere with other heart or lung medicines.
- Dorzolamide (sulfonamide-related) can cause allergic skin reactions; rare metabolic or electrolyte effects with improper use.
Who should use caution
- Asthma, COPD, or other lung problems; certain heart rhythm disorders; slow heart rate or certain kinds of heart block.
- Known sulfonamide allergy (inform your doctor; it doesn’t automatically rule out use, but requires caution).
- Pregnancy or breastfeeding; talk with your clinician about risks and alternatives.
- If you’re taking other eye medicines, especially other beta-blocker eye drops or systemic beta-blockers, discuss with your doctor to avoid excessive beta-blockade.
When to contact a clinician
- Severe eye pain, vision changes, or signs of an eye infection.
- Symptoms of a systemic beta-blocker reaction (very slow heart rate, dizziness, wheezing).
- Signs of an allergic reaction (rash, swelling, trouble breathing).
If you’d like, tell me:
- Are you currently prescribed this medication or considering it?
- Do you have asthma, COPD, heart rhythm problems, or a sulfa allergy?
- Do you wear contact lenses?
I can tailor the information to your situation or help with any specific questions about dosing, safety, or what to expect. This is informational only and not a substitute for a clinician’s advice.