Nepafenac is administered locally in the eye and hepatic exposure is insignificant.

Benzophenone

Nepafenac is a non-steroid anti-inflammatory prodrug used in the treatment of postoperative pain and inflammation associated with cataract surgery (SPC). It is administered as eye drops.

Following the 3 times daily dosing of nepafenac eye drops in both eyes, maximal plasma concentration of nepafenac and amfenak were in the order of 0,5 ng/ml (SPC) which is well below 1,0 µM concentration and hepatic exposure is therefore regarded as insignificant.

Nepafenac is converted by ocular tissue hydrolases to the active drug amfenac. Amfenac is further hydroxylated, bound to glucoronic acid and excreted as glucuronide conjugates (SPC). In vitro studies show that neither nepafenac nor amfenac show inhibitory effects on the major CYP450 metabolizing enzymes (CYP3A4, CYP2C9) (SPC).