Brinzolamide / Timolol

What it is and how it works

Brinzolamide inhibits carbonic anhydrase II in the ciliary body, reducing bicarbonate formation and aqueous humour secretion. Timolol, a non-selective beta-adrenoceptor blocker, also reduces aqueous production; the combination lowers intra-ocular pressure more than either agent alone.

Indications

Reduction of elevated intra-ocular pressure in open-angle glaucoma or ocular hypertension when monotherapy provides insufficient reduction.

Dosage and administration (summary)

One drop into the affected eye(s) twice daily; shake well before use. Separate from other topical eye medicines by at least 5 minutes.

Contraindications

Bronchial asthma or history of asthma, severe COPD; sinus bradycardia, sick sinus syndrome, second- or third-degree AV block, overt cardiac failure or cardiogenic shock; severe allergic rhinitis; hyperchloraemic acidosis; severe renal impairment; hypersensitivity to sulfonamides.

Warnings and precautions

Timolol is absorbed systemically and may cause bradycardia, hypotension, bronchospasm and masking of hypoglycaemia or thyrotoxicosis signs; nasolacrimal occlusion reduces systemic absorption. Brinzolamide is a sulfonamide — discontinue if serious hypersensitivity reactions occur; caution with corneal endothelial compromise. Transient blurred vision and taste disturbance are common; remove soft contact lenses before instillation (benzalkonium chloride).

Pregnancy

Should not be used in pregnancy unless clearly necessary; monitor the neonate for beta-blockade if used near delivery.

Storage and supply

Store according to the manufacturer’s instructions (no special temperature requirement for most products); discard 4 weeks after first opening.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.