The FDA has approved phentolamine ophthalmic solution (Ryzumvi) 0.75% for treatment-induced mydriasis, Viatris and Ocuphire Pharma .
The approval stipulates use of the eye drops to manage pupillary dilation by adrenergic agonists or parasympatholytic agents. An estimated 100 million people in the U.S. undergo comprehensive eye exams that include dilation of the pupils, or mydriasis. Persisting for up to 24 hours, mydriasis can cause light sensitivity, blurred vision, and other ocular side effects that can affect a person's ability to read, work, and drive.
Support for the approval came from the MIRA clinical trial program, comprising four phase I-III clinical trials, including one study involving pediatric patients. Collectively, the studies involved more than 600 patients ages 12-80, who had mydriasis induced by phenylephrine, tropicamide, or a combination of hydroxyamphetamine hydrobromide and tropicamide.
Study participants were randomized to phentolamine ophthalmic solution or placebo, administered 1 hour after pupillary dilation. In , significantly more patients treated with the active eye drops had a reduction in baseline pupil diameter to ≤0.2 mm (P<0.01) at assessments that occurred from 1 through 24 hours after mydriasis induction. Subgroup analyses showed similar efficacy across all age groups.
The most commonly reported ocular adverse events (AEs) among patients treated with phentolamine ophthalmic solution were stinging and burning (16%) and conjunctival hyperemia (12%). The only non-ocular AE in the trials was dysgeusia (6%).
According to the companies' statement, pupillary dilation is controlled primarily by radial iris dilator muscles, which are activated by alpha-1 adrenergic receptors. Phentolamine binds to the receptors on radial iris dilator muscles surrounding the pupil to reduce pupil diameter.
Company officials expect the phentolamine eye drops to become available in the U.S. during the first half of 2024.