| Click Here to view online. |
 |
|
|
| |
Phentolamine (Nyxol) Clinical Trials Next in the Pipeline for Presbyopia
|
By Y. Ralph Chu, MD
|
While VUITY (pilocarpine hydrochloride ophthalmic solution, 1.25%, Allergan) is the first and only FDA-approved drop for presbyopia correction currently, the pipeline in this category remains robust and exciting. Specifically, my practice has been involved with the FDA clinical trial for phentolamine ophthalmic solution, 0.75% (Nyxol, Ocuphire Pharma). Phentolamine is a non-selective alpha-1 and alpha-1 adrenergic antagonist that binds to the alpha-1 receptors on the iris dilator muscle. This mechanism allows moderate decrease in pupil diameter which improves reading vision without sacrificing distance vision.
One potential advantage of phentolamine’s mechanism of action is that it does not engage the ciliary muscle, compared with cholinergic miotics, that minimize the risk of accommodative spasm, headaches and/or retinal issues. Also, phentolamine’s duration of action is over 12 hours, which gives patients the option of to instill the drop before bedtime so they don’t need to reach for their glasses when they wake up.
Phentolamine ophthalmic solution has been studied in 12 clinical trials, including four Phase 3 FDA trials, and has a favorable safety profile with no headaches or systemic side effects such as changes in heart rate or blood pressure. Investigators noticed mild and transient redness in some patients due to the on-target effect on smooth muscle in conjunctival blood vessels.
The FDA clinical trials are pursuing two different indications: phentolamine alone or phentolamine in combination with 0.4% low-dose pilocarpine for additional pupil modulation effects. Early results from these trials appear promising. We are excited about the expanding choices that will be available to all eye care providers and patients in the future. |
 |
Ralph Chu, MD, is the founder and medical director of Chu Vision Institute in Bloomington, MN. |
|
|
|
|
| Follow us: |
|
|
|
