Timolol

TIMOPTIC

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Pronunciation: TYE-moe-loel (tim-OP-tik)

Timolol ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Timolol ballicule

Timolol TIMOPTIC mascot mnemonic cartoon — Visual mnemonic: Timolol mascot
**“Timmy Time”**
LOL cap → β blocker

What it isBeta-receptor antagonist eye drop that reduces aqueous production; open-angle glaucoma.

Why this oneThe benchmark ocular beta blocker, it is inexpensive and adds effectively to a prostaglandin analog.

What limits itEye drops can still cause bradycardia and bronchospasm; use punctal occlusion and avoid in asthma or heart block.

Timolol molecular structure (skeletal formula) — Molecular structure: Timolol

FDA-approved for

hypertension (1978)
glaucoma (1978)

FDA label

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FDA dosing	Population	Start	Target	Max
Elevated intraocular pressure (ocular hypertension, open-angle glaucoma)	Adults	1 drop of 0.25% in affected eye(s) BID	1 drop of 0.5% BID if response inadequate; may change to 1 drop QD once IOP controlled	1 drop of 0.5% BID (higher doses add no IOP reduction)

Titration Approximately 4 weeks (IOP response may take a few weeks to stabilize)

Renal Undefined

Hepatic Undefined

Systemically absorbed — beta-blocker class adverse reactions (bronchospasm, cardiac failure) can occur with eye drops.

Instructions

Instill in affected eye(s)
When switching to once daily, confirm response with IOP measured at different times of day (diurnal variation)
Do not combine with a second topical beta-blocker

Available strengths

drops 0.25, 0.5 %
tab 5, 10, 20 mg
sol 2.5, 3.4, 5, 6.8 mg/mL

Contraindications

Bronchial asthma or history of bronchial asthma; severe COPD
Sinus bradycardia; second- or third-degree AV block
Overt cardiac failure
Cardiogenic shock

Cautions

Systemic absorption — severe respiratory/cardiac reactions incl. death
Cardiac failure
Obstructive pulmonary disease
Major surgery (impaired reflex cardiac response under anesthesia)
Diabetes mellitus (masks hypoglycemia)
Thyrotoxicosis (masks signs; abrupt withdrawal → thyroid storm)

Adverse reactions

Burning and stinging on instillation (~1 in 8)
Headache
Asthenia/fatigue
Bradycardia
Arrhythmia
Hypotension
Dizziness
Bronchospasm, dyspnea
Ocular irritation (conjunctivitis, blepharitis, keratitis)
Dry eyes
Visual disturbances
Nausea

Pregnancy No adequate human studies; no malformations in animals at high oral doses — use only if benefit justifies fetal risk.

Lactation Detected in human milk after oral and ophthalmic dosing; decide whether to discontinue nursing or the drug.

Cost

Timolol (TIMOPTIC)

Strength		#/mo	generic $/unit	CostPlus
0.25 %	drops	per unit		not offered
0.5 %	drops	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Timolol is dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

Available combined with: dorzolamide / timolol

Generic entry2016

NO BOXED WARNINGS

Principal riskSystemic beta blockade from eye drops: bradycardia and bronchospasm

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger2 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryUnknown / historical label unavailable

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.

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Memory aids: interaction avatars

CYP2D6 substrate

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