Tretinoides

Tretinoides, commonly referred to as retinoids in English, are a class of chemical compounds derived from vitamin A. They include natural retinoids such as retinol and retinal, and synthetic derivatives such as tretinoin (all-trans retinoic acid), isotretinoin, adapalene, tazarotene, and bexarotene. They exert biological effects by binding to nuclear receptors—retinoic acid receptors (RARs) and, for some compounds, retinoid X receptors (RXRs)—which modulate gene expression and influence cell differentiation, proliferation, and apoptosis.

In clinical use, retinoids have broad dermatological and oncological applications. Topical retinoids like tretinoin, adapalene, and tazarotene are commonly prescribed for acne management and for reducing signs of photoaging and improving skin texture. Oral isotretinoin is reserved for severe nodular acne. In oncology, all-trans retinoic acid is a standard part of treatment for acute promyelocytic leukemia (APL). Some retinoids are explored for other cancers and dermatologic conditions, owing to their differentiation- and anti-proliferation-inducing properties.

Formulation and pharmacokinetics vary by agent and route. Topical preparations come as creams, gels, or lotions, while systemic retinoids are given orally. They are lipophilic and are metabolized in the liver, with pharmacokinetics influenced by the specific compound. Dosing depends on indication, formulation, and patient factors, often with concomitant photoprotection.

Safety and regulation are important considerations. Retinoids are teratogenic; systemic use typically requires strict pregnancy prevention programs and monitoring of liver function and lipid levels. Common adverse effects include irritation, dryness, peeling, and increased photosensitivity. Long-term or high-dose systemic retinoids require careful medical supervision.