Latanoprost + Timolol

Ophthalmic
Ocular hypertension, Open-angle glaucoma

Reactive airway diseases e.g.bronchial asthma or a history of bronchial asthma, severe COPD. Sinus bradycardia, 2nd or 3rd degree AV block, overt cardiac failure, cardiogenic shock.

Monitor heart rate and signs of cardiac failure in patients with history of severe cardiac disease. May worsen Prinzmetal angina, severe peripheral and central circulatory disorders and hypotension. Monitor for signs of bronchospasm in asthmatic patients. β-blockers may mask signs and symptoms of acute hypoglycaemia and hyperthyroidism. Prolonged treatment with latanoprost may change eye colour by increasing the amount of brown pigment in the iris especially in patients with mixed coloured irides; regular eye examination is recommended. Caution when used in aphakic patients due to risk of macular oedema. Contact lenses should be removed during application and reinserted at least 15 minutes after application. May cause transient blurring of vision; patients should not drive or operate machinery until this resolves. Pregnancy and lactation.

Increased iris pigmentation, eye irritation, eye pain, stinging and burning sensation. Rarely, bradycardia, arrhythmia, CHF, bronchospasm and allergic reactions.

Symptoms of systemic timolol overdose: Bradycardia, hypotension, bronchospasm and cardiac arrest. Treatment is symptomatic and supportive. Latanoprost overload can cause ocular irritation and conjunctival hyperaemia, no other ocular or systemic side effects are known. If latanoprost is accidentally ingested orally, gastric lavage may be used. Treatment is symptomatic and supportive.

Additive effect on the intraocular pressure and other systemic effects may occur when used with oral β-blockers, calcium channel blockers, guanethidine, antiarrhythmics, digitalis glycosides or parasympathomimetics. Concurrent use of ≥2 ophthalmic prostaglandin analogues may lead to paradoxical increase in intraocular pressure. Mydriasis may occur when used concurrently with epinephrine. β-blocker may increase hypoglycaemic effect of antidiabetic agents.

Description: Latanoprost is an analogue of prostaglandin F_2α; it reduces intraocular pressure (IOP) by increasing outflow of aqueous humour. Timolol is a non-selective adrenergic blocker. It lowers IOP by decreasing the formation of aqueous by the ciliary epithelium.
Pharmacokinetics:
Absorption: Latanoprost: Well-absorbed through the cornea; a prodrug that is activated by the esterases in the cornea.
Distribution: Latanoprost: Active metabolite has a small volume of distribution of 0.16 L/kg and protein binding of 87%.
Metabolism: Latanoprost: Active metabolite is mainly metabolised hepatically. Timolol: Largely metabolised in the liver.
Excretion: Latanoprost: Plasma half-life of active metabolite is about 17 minutes and the metabolites are excreted primarily in the urine. Timolol: Plasma half-life is about 6 hr and the metabolites are mainly excreted in the urine.

Store at 2-8°C. For opened bottles, may store below 25°C.

Antiglaucoma Preparations