The safety and efficacy of unoprostone 0.15% versus brimonidine 0.2%

A review of neuropsychiatric adverse events from topical ophthalmic brimonidine

Brimonidine is a first-line topical medication for increased intraocular pressure and glaucoma which may be used alone or in conjunction with other topical therapies. Its structural and pharmacological comparabilities to clonidine give way to the hypothesis that it may cause neuropsychiatric side effects. The majority of case reports citing brimonidine toxicity, either for topical or peripheral exposure, include pediatric age groups but especially infants. Among the latter, a dose-response phenomenon is evident. Dose-response correlates have also been shown among adults. Case series and prospective double-blind treatment studies also give evidence for the occurrence of several central nervous system adverse reactions. Topical ophthalmic brimonidine use should be followed for the occurrence of neuropsychiatric disturbances generally, and enhanced vigilance should be maintained for at-risk populations.

An evidence-based review of unoprostone isopropyl ophthalmic solution 0.15% for glaucoma: place in therapy

Glaucoma is a progressive, neurodegenerative optic nerve disease that can cause significant visual morbidity and affects over 60 million people worldwide. The only known modifiable risk factor for glaucoma at this time is elevated intraocular pressure (IOP), which may be treated with medications, laser therapy, and/or incisional surgery. Topical ocular medications are commonly used as first-line therapy for glaucoma, although side effects may limit their use. Unoprostone is a novel 22-carbon ocular hypotensive agent that may be advantageous in treating some patients with open angle glaucoma or ocular hypertension. Unlike the 20-carbon prostanoids, such as latanoprost, that lower IOP primarily through an increase in uveoscleral outflow, unoprostone may lower IOP through increased aqueous outflow via the conventional trabecular meshwork pathway. Although not as efficacious as other prostanoids, unoprostone is effective for IOP reduction both as monotherapy and adjunctive therapy with timolol. Unoprostone has decreased affinity for the prostaglandin F2α receptor, which may explain its well tolerated ocular and systemic side effect profile compared with other prostanoids.

Brimonidine 0.2% vs unoprostone 0.15% both added to timolol maleate 0.5% given twice daily to patients with primary open-angle glaucoma or ocular hypertension

PURPOSE

To compare the efficacy and safety of brimonidine 0.2% vs unoprostone 0.15%, both added to timolol maleate 0.5% each given twice daily.

METHODS

In this prospective, multi-centred, double-masked, crossover comparison, patients were randomized to one treatment group for a 6-week treatment period, and then crossed over to the opposite treatment. Measurements were performed at 0800, 1000, 1600, 1800, and 2000 h at baseline and at the end of each treatment period.

RESULTS

In all, 33 patients entered this trial and 29 completed. The baseline trough intraocular pressure (IOP) was 23.3+/-2.4 and the diurnal curve IOP was 22.0+/-1.3 mmHg. For the brimonidine and timolol maleate treatment group, the trough IOP was 21.6+/-3.3 and the diurnal curve IOP was 19.8+/-2.1 mmHg, while the timolol and unoprostone treatment showed a trough IOP of 20.9+/-3.8 and a diurnal curve IOP of 19.3+/-2.4 mmHg. There was no significant difference between treatment groups at any time point for the diurnal curve, or in the reduction from baseline (P>0.05). Both treatments failed to statistically reduce the IOP from baseline at 1800 h. There was no difference between treatment groups regarding ocular and systemic unsolicited adverse events, but patients admitted to more dryness (P=0.02) and burning upon instillation (P<0.0001) with unoprostone by survey.

CONCLUSION

Brimonidine 0.2% or unoprostone 0.15% added to timolol maleate 0.5% provide similar efficacy and safety throughout the daytime diurnal curve.