Amfenac is a nonsteroidal anti-inflammatory drug (NSAID) primarily used for its analgesic and anti-inflammatory properties. It works by inhibiting cyclooxygenase (COX) enzymes, there by reducing the production of prostaglandins responsible for pain and inflammation. Amfenac was developed as part of research into effective NSAIDs and is known as the active metabolite of nepafenac, an ophthalmic prodrug. Researchers found that amfenac provides potent anti-inflammatory effects, especially in ocular tissues, which led to its use in eye-related conditions. Over time, it gained recognition in clinical practice, particularly in ophthalmology for managing postoperative inflammation and pain following cataract surgery. Today, amfenac remains an important medication for reducing inflammation and discomfort, especially in eye conditions and certain inflammatory disorders.
BRAND NAMES
Nevanac: A widely recognized ophthalmic brand containing Nepafenac, which is converted in the eye to amfenac.
Amfenac (generic): Available in some markets as a direct formulation, especially for research or specialized use.
Nevaclot / Nepaflam: Regional brands (mainly in Asia) containing nepafenac that acts via amfenac.
Acular (related NSAID): Contains Ketorolac, often mentioned alongside amfenac-class drugs for similar ophthalmic uses.
MECHANISM OF ACTION
Amfenac acts primarily as a nonsteroidal anti-inflammatory drug (NSAID) by inhibiting cyclooxygenase (COX-1 and COX-2) enzymes, which are responsible for converting arachidonic acid into prostaglandins key mediators of inflammation, pain, and swelling. By reducing prostaglandin synthesis, amfenac effectively decreases inflammation, relieves pain, and limits tissue swelling. In ophthalmic applications, it is produced locally in ocular tissues from its prodrug Nepafenac, enabling targeted anti-inflammatory action, especially after procedures like cataract surgery. Unlike mucolytic agents, amfenac does not influence mucus secretion or clearance but instead works by suppressing inflammatory pathways to provide therapeutic relief.
PHARMACOKINETICS
Absorption :
Amfenac is not usually given directly but is formed in the eye after administration of its prodrug Nepafenac. Nepafenac easily penetrates the cornea due to its lipophilic nature and is quickly converted into active amfenac, enabling effective local absorption in ocular tissues with minimal systemic exposure.
Distribution:
Amfenac is mainly distributed within ocular tissues after topical administration of its prodrug Nepafenac, where it penetrates structures such as the cornea, aqueous humor, iris, and ciliary body to exert its anti-inflammatory effects, while systemic distribution remains minimal due to its localized action.
Metabolism :
Amfenac is formed in ocular tissues from its prodrug Nepafenac and, after exerting its effect, is further metabolized mainly in the liver into inactive metabolites that are eliminated via the kidneys, with minimal systemic involvement due to low absorption.
Excretion:
Amfenac is primarily excreted as inactive metabolites via the urine, with only a minimal amount eliminated unchanged, while systemic exposure is low due to its localized ocular administration, and fecal excretion is negligible.
PHARMACODYNAMICS
Amfenac is a potent NSAID with pharmacodynamic effects centered on inhibiting cyclooxygenase (COX) enzymes, thereby reducing prostaglandin synthesis. Its main actions are anti-inflammatory, analgesic, and anti-swelling, particularly in ocular tissues. Amfenac helps control postoperative inflammation, pain, and discomfort, with minimal systemic effects due to its localized delivery.
ADMINISTRATION
Amfenac is an NSAID given as 0.1% eye drops to reduce pain and inflammation after eye surgery. Usually, one drop is applied to the affected eye three times daily, starting a day before surgery and continuing for up to two weeks. Hands should be washed before use, contact lenses removed, and the dropper should not touch the eye. Side effects may include redness or irritation, and use should be avoided in those allergic to NSAIDs.
DOSAGE AND STRENGTH
Amfenac is administered ophthalmically via its prodrug Nepafenac. The standard dosage for adults is one drop in the affected eye three times daily, typically starting one day before ocular surgery and continuing for up to two weeks postoperatively to control inflammation and pain. Pediatric dosing is generally one drop three times daily, with duration adjusted according to clinical response. Topical ocular administration ensures localized therapeutic effect, and systemic dosing is not recommended.
DRUG INTERACTIONS
Amfenac can interact with other NSAIDs, corticosteroids, or medications that affect bleeding or renal function, although systemic interactions are minimal due to its localized ocular use. Caution is advised in patients with known hypersensitivity to amfenac, nepafenac, or other NSAIDs, as re-exposure can trigger allergic reactions or ocular irritation.
FOOD INTERACTIONS
Amfenac has no significant interactions with food, and its ophthalmic formulation can be used regardless of meals. Since it is administered locally to the eye, oral intake, alcohol, or diet does not affect its absorption or efficacy.
CONTRAINDICATIONS
Amfenac is contraindicated in patients with a known hypersensitivity to amfenac, nepafenac, or other NSAIDs. It should also be avoided in individuals with active eye infections, severe corneal epithelial defects, or a history of ocular surface disease that could be worsened by topical NSAID use.
SIDE EFFECTS
Eye irritation or discomfort
Burning or stinging sensation upon instillation
Redness of the eye (conjunctival hyperemia)
Itching or watering of the eye
Blurred vision or transient visual disturbances
Foreign body sensation in the eye
Rarely, corneal complications with prolonged use
Systemic side effects are uncommon due to minimal absorption
TOXICITY
The most serious toxicity of Amfenac is ocular surface damage, such as corneal epithelial defects or ulceration, especially with prolonged use. Other potential toxicities include eye irritation, redness, burning, or allergic reactions. Systemic toxicity is rare due to minimal absorption, but caution is advised in patients with NSAID hypersensitivity or preexisting ocular conditions.
