indication

For the treatment of pain and inflammation associated with cataract surgery.

pharmacology

Low but quantifiable plasma concentrations of nepafenac and amfenac were observed in the majority of subjects 2 and 3 hours postdose, respectively, following bilateral topical ocular TID dosing of nepafenac ophthalmic suspension, 0.1%. The mean steady-state Cmax for nepafenac and for amfenac were 0.310 ± 0.104 ng/ml and 0.422 ± 0.121 ng/ml, respectively, following ocular administration.

mechanism of action

Nepafenac is a prodrug. After penetrating the cornea, nepafenac undergoes rapid bioactivation to amfenac, which is a potent NSAID that uniformly inhibits the COX1 and COX2 activity.

toxicity

Ocularly applied non-steroidal anti-inflammatory drugs may cause increased bleeding of ocular tissues (including hyphemas) in conjunction with ocular surgery.

biotransformation

Nepafenac (prodrug) is deaminated to amfenac (active compound) in the ciliary body epithelium, retina, and choroid by intraocular hydrolases. Subsequently, amfenac undergoes extensive metabolism to more polar metabolites involving hydroxylation of the aromatic ring leading to glucuronide conjugate formation.

absorption

Nepafenac rapidly cross the cornea (6 times faster than diclofenac in vitro).

route of elimination

After oral administration of 14C-nepafenac to healthy volunteers, urinary excretion was found to be the major route of radioactivity elimination, accounting for approximately 85% of the dose, while fecal excretion represented approximately 6% of the dose. Nepafenac (prodrug) and amfenac (active compound) were not quantifiable in the urine.