Latanoprost is safe and well tolerated as adjunctive therapy for long-term treatment of the most common form of glaucoma, according to an article in the July issue of the Archives of Ophthalmology, one of the JAMA/Archives journals.
Glaucoma is a condition in which the pressure inside the eyes rises. If untreated, glaucoma may damage the optic nerve and other parts of the eye, and my lead to blindness. According to information in the article, latanoprost is a derivative of the chemical prostaglandin F2-alpha. Prostaglandin derivatives have been shown to help lower intraocular pressure (IOP).
Albert Alm, M.D., of University Hospital, Uppsala, Sweden, and colleagues evaluated the safety and efficacy of 0.005 percent latanoprost administered once daily for five years as adjunctive therapy to other IOP-lowering drugs in patients whose IOP was uncontrolled with a single form of therapy. Patients with primary open-angle glaucoma (the most common form of glaucoma in the West) or exfoliation glaucoma (a form of glaucoma in which abnormal deposits are found on the surface of the lens and on other structures inside the eyeball) who completed a three-year, open-label, uncontrolled prospective trial could enter a two-year extension phase.
Among 519 patients enrolled in the original three-year study, 380 enrolled in the extension phase. The researchers examined the incidence and progression of increased iris pigmentation among the patients, assessed from high-resolution color photographs taken at baseline and at 14 subsequent visits. IOP and adverse events were also recorded.
"In all, 127 (33.4 percent) of 380 patients who continued in the extension phase had developed increased iris pigmentation in one or both eyes after five years of adjunctive therapy with 0.005 percent latanoprost," the authors write. "In particular, more than three quarters of the patients with either green-brown or yellow-brown eyes were affected."
For those who developed iris pigmentation, onset occurred during the first eight months in 74 percent and during the first 24 months in 94 percent.
The researchers also evaluated the long-term efficacy of latanoprost in lowering IOP when administered as adjunctive therapy. "The overall mean intraocular pressure reduction from baseline of 25 percent was sustained with no need for change in intraocular pressure-lowering treatment in 70 percent of the eyes," they report.
Almost all ocular and systemic adverse events were mild in intensity. These included visual field defect (a blind spot or blind area within the normal bounds of vision), eye irritation, cataract (clouding of the lens portion of the eye), and eye abnormality.
"The results of this open-label, multicenter, multinational, uncontrolled study demonstrate that 0.005 percent latanoprost administered once daily as adjunctive therapy for up to five years is safe and effective in reducing IOP in patients with primary open-angle and exfoliative glaucoma," the authors conclude. "Treatment with latanoprost was generally well tolerated both locally and systemically.