Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Timolol is a non-selective beta blocker used mostly as eye drops: it reduces the production of fluid inside the eye, lowering eye pressure in glaucoma and ocular hypertension. Tablets were used for high blood pressure and migraine, and a gel form treats infant haemangiomas. It is sold as Timoptic, among other names.
Timolol is broken down mainly by CYP2D6, and enough of an eye drop reaches the blood to slow the heart in some people; studies linked CYP2D6 poor metabolizer status to higher levels and more slowing of the heart rate. Studies have also looked at ADRB1 for eye pressure response. The findings come from a few studies, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Timolol. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CYP2D6 CYP2D6*1, CYP2D6*3, CYP2D6*4, CYP2D6*5: Level 3. Other. 2.
rs16947: Level 3. Toxicity: Bradycardia. 1.
ADRB1 rs1801252: Level 3. Efficacy. 1.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Beta Blockers (class) (Beta Blockers)
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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