Timolol maleate
Glaucoma · Rx
Trade namesTimoptic, Timoptic-XE (gel), Istalol, Betimol, Timoptic Ocudose (PF)
Drug classNon-selective beta-blocker
Strength0.25%, 0.5%
AvailabilityRx
Mechanism of actionNon-selective beta-adrenergic antagonist; reduces aqueous humour production by the ciliary epithelium. ~20-25% IOP reduction.
Indication / reason for useOpen-angle glaucoma and ocular hypertension; common second agent or fixed-combination partner.
Usual adult dosing1 drop once or twice daily (gel-forming and Istalol are once daily). Punctal occlusion / eyelid closure for 2 min reduces systemic absorption.
PreservativeBAK 0.01% (Ocudose is preservative-free) , a preservative-free option exists
Contact lensesRemove lenses; reinsert after 15 minutes. BAK also accumulates in soft lenses.
Common / important adverse effectsSystemic beta-blockade: bradycardia, hypotension, bronchospasm, worsening heart block/CHF, fatigue, depression, reduced exercise tolerance, masking of hypoglycemia symptoms, impotence; ocular stinging, dry eye, corneal anesthesia.
Contraindications & cautionsReactive airway disease / asthma / severe COPD, sinus bradycardia, 2nd/3rd-degree AV block, overt cardiac failure, cardiogenic shock.
Pregnancy / lactationBeta-blocker of choice among ocular hypotensives if one is needed; monitor neonate for bradycardia if used near term. Avoid during breastfeeding or monitor infant.
Practice notesLeast effective at night (aqueous production already low during sleep). Ask about inhalers and pulse before prescribing.
Chair-side reference only. Dosing, contraindications and pregnancy guidance here are not exhaustive. Confirm against the current prescribing information and the patient’s full history before prescribing or advising.