All topical retinoids normalize keratinization and appear to have anti-inflammatory effects; whether any one topical retinoid is more effective than any other is not clear. Many dermatologists now recommend topical retinoids for first-line treatment of acne; they can be used alone or in combination with antibiotics to treat both inflamed and noninflamed acne lesions, or for maintenance treatment. Retinoid/antimicrobial combinations are more effective than either component alone, particularly for patients with inflammatory lesions.1

Adverse effects of topical retinoids include dry skin, scaling, photosensitivity, erythema, burning, and pruritus. Although only small amounts of the drug are absorbed systemically following topical application, adapalene is classified as category C (teratogenic in rats; no adequate studies in pregnant women) for use during pregnancy.

Adapalene (Differin, and generics) is available by prescription in 0.1% gel, cream, and lotion formulations and in a 0.3% gel formulation. It is also available by prescription in combination with the oxidizing agent benzoyl peroxide (Epiduo; Epiduo Forte).

The cost of one 45-gram tube ranges from about $157 for generic adapalene to $580 for Differin.2 The cost of OTC Differin Gel 0.1% was not available at the time of publication.