Latanoprost

Pharmacological properties

the active substance of the drug xalatan - latanoprost - is an analogue of prostaglandin f2α, a selective agonist of the prostanoid receptor fp, which reduces intraocular pressure (IOP) by increasing the outflow of intraocular fluid from the eye. a decrease in IOP in a person begins approximately 3-4 hours after the administration of the drug, and the maximum effect is observed after 8-12 hours. A decrease in IOP is maintained for at least 24 hours.

Basic studies have shown that Xalatan is effective in monotherapy. In addition, clinical studies of the combined use of the drug have been conducted. They included studies whose results indicate that latanoprost is effective in combination with β-adrenergic blockers (timolol). Short-term (1 or 2 weeks) studies show that the action of latanoprost is additive when used in combination with adrenergic receptors agonists (dipivalyl epinephrine), oral carbonic anhydrase inhibitors (acetazolamide) and at least partially additive when used with cholinergic agonists (pilocarpine).

The results of clinical studies indicate that latanoprost does not significantly affect the production of intraocular fluid. No effect of latanoprost on the blood-ophthalmic barrier was revealed.

Latanoprost did not cause leakage of fluorescein in the posterior segment of the human pseudophakic eyes during short-term treatment.

No significant pharmacological effects of latanoprost in clinical doses on the cardiovascular and respiratory systems have been identified.

Children. The effectiveness of Xalatan in patients ≤18 years of age was demonstrated in a 12-week double-blind clinical trial of latanoprost compared with timolol in 107 patients who were diagnosed with intraocular hypertension and childhood glaucoma. In this study, the gestational age of the newborn should have been at least 36 weeks. Patients received 0.005% latanoprost 1 time per day or 0.5% timolol (or a choice of 0.25% for patients under the age of 3 years) 2 times a day. The primary endpoint for efficacy was the average IOP reduction relative to baseline at week 12 of the study. The average IOP reduction in the groups of patients receiving latanoprost and timolol was similar. In all studied age groups (from birth to 3 years, 3–12 years and 12–18 years), the average reduction in IOP at the 12th week of the study in patients receiving latanoprost and patients receiving timolol was similar. However, data on the effectiveness of latanoprost in the age group of patients from birth to 3 years were obtained only for 13 patients and there was no significant effectiveness in 4 patients who represented the age group from birth to 1 year in the clinical study. Data on the use of the drug in preterm infants (those born before the 36th week of pregnancy) are not available.

IOP reduction rates in the subgroup of patients with primary congenital glaucoma (PVG) / infant glaucoma were similar in patients treated with latanoprost and patients treated with timolol. The results in the non-PVG subgroup (i.e., patients with, for example, juvenile open-angle glaucoma, aphakic glaucoma) and PVG patients were similar.

The effect on IOP was manifested after the 1st week of treatment (table) and continued for 12 weeks of the study in the same way as in adults.

Table

IOP reduction (mmHg) at the 12th week of the study, depending on the group of active treatment and the initial diagnosis

* SP - standard error.

** Corrected calculation indicator based on the covariance analysis model (ANCOVA).

Pharmacokinetics Latanoprost (molecular weight - 432.58) is an isopropyl ether of the active substance, that is, a prodrug that is itself inactive, but after hydrolysis with the formation of acid, latanoprost becomes biologically active.

Prodrugs penetrate well through the cornea, and all drugs that enter the intraocular fluid hydrolyze when passing through the cornea.

Human studies have shown that C_max in IOP is achieved after 2 h