Adapalene

Adapalene is a synthetic retinoid-like topical medication used primarily to treat mild to moderate acne vulgaris. It is available in various formulations, including gels, creams, and lotions, with common concentrations of 0.1% and 0.3%. In many regions, the 0.1% formulation is sold over the counter, while higher strengths and formulations may require a prescription.

The drug acts as a retinoid receptor agonist, with relatively selective activity on retinoic acid receptors, particularly RAR beta and gamma. By normalizing keratinocyte differentiation and reducing abnormal keratinization, adapalene helps prevent the formation of microcomedones. It also exerts anti-inflammatory effects, contributing to a reduction in inflammatory acne lesions.

Adapalene is indicated for people usually aged 12 years and older who have comedonal or inflammatory acne. It is typically applied once daily in a thin layer to clean, dry skin, often at bedtime. If irritation occurs, a patient may reduce frequency or use a moisturizer. In combination therapies, adapalene may be paired with benzoyl peroxide or antibiotics, though regimens should follow medical guidance to minimize irritation.

Common adverse effects include local skin irritation, redness, dryness, and flaky skin. Photosensitivity can increase, so sun protection is advised during treatment. Pregnancy is categorized as warning to consult a clinician, and patients should discuss use if pregnant or planning pregnancy. Systemic exposure from topical use is minimal.

Pharmacokinetically, adapalene has low systemic absorption and is largely metabolized locally, with excretion primarily via the urine. Brand examples include Differin, among others. The medication is generally well tolerated when used with appropriate precautions and gradual initiation.