clonidine vs dorzolamide/timolol
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Side-by-side comparison of clonidine and dorzolamide/timolol. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
7.8 Clonidine Oral beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine.
Catapres
Cosopt
Clonidine (Catapres) is a medicine used to treat high blood pressure. It can be used alone or with other blood pressure medicines.
Cosopt is an eye drop that lowers pressure inside the eye. It combines two medicines to treat glaucoma and high eye pressure.
Clonidine is used to treat high blood pressure. High blood pressure can lead to heart disease, stroke, and kidney problems. This medicine helps to lower your blood pressure to a safer level.
Cosopt is used to lower high pressure in your eyes. It treats open-angle glaucoma and ocular hypertension. These conditions can damage the optic nerve and cause vision loss. Cosopt is for people who haven't responded well to beta-blocker eye drops alone.
Clonidine works in the brain to lower blood pressure. It tells your blood vessels to relax and widen. This makes it easier for blood to flow through your body, which lowers blood pressure.
Cosopt has two medicines. Dorzolamide lowers eye pressure by reducing fluid production in the eye. Timolol lowers eye pressure by blocking certain receptors in the eye.
- • Dry mouth (occurs in about 40 out of 100 people)
- • Drowsiness (occurs in about 33 out of 100 people)
- • Dizziness (occurs in about 16 out of 100 people)
- • Constipation (occurs in about 10 out of 100 people)
- • Feeling sleepy or sedated (occurs in about 10 out of 100 people)
- • Bitter, sour, or unusual taste
- • Eye burning or stinging
- • Redness of the eye
- • Blurred vision
- • Superficial punctate keratitis (small spots on the cornea)
- Pain 3,038
- Fatigue 2,925
- Nausea 2,920
- Headache 2,798
- Hypertension 2,595
- Treatment not working 1,369
- Tiredness 444
- Headache 356
- Pain 321
- Eye pain 292
If you suddenly stop taking clonidine, your blood pressure may increase. This can cause serious problems. Talk to your doctor before stopping this medicine.
Cosopt contains timolol, which can cause breathing problems like asthma. If you have asthma or severe lung disease, you should not use Cosopt. Cosopt can also cause heart problems, including heart failure. If you have heart problems, talk to your doctor before using Cosopt. Cosopt contains dorzolamide, a sulfonamide. Rarely, severe reactions to sulfonamides, including fatal reactions, have occurred. If you have a sulfonamide allergy, you should not use Cosopt.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if clonidine will harm your unborn baby. Talk to your doctor if you are breastfeeding.
It is not known if Cosopt will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if Cosopt passes into breast milk. Talk to your doctor about the best way to feed your baby if you use Cosopt.
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How to Read This clonidine vs dorzolamide/timolol Comparison
clonidine is classified in the Central Alpha-2 Agonist drug class, while dorzolamide/timolol sits within the CAI / Beta-Blocker Combination (Ophthalmic) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, clonidine has 14,276 submissions while dorzolamide/timolol has 2,782. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to the beta-blocker in the eye drops can make blood pressure rise even higher if you suddenly stop taking your clonidine medication.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for clonidine or dorzolamide/timolol.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.