Agentsretinoids

Agentsretinoids is a nonstandard term used to describe pharmacological compounds that influence the retinoid signaling pathway. In most literature the term retinoids or retinoid-like agents is used. These compounds act by engaging retinoic acid receptors (RARs) and retinoid X receptors (RXRs) or by altering retinoid metabolism, thereby modulating the transcription of genes involved in cell differentiation, proliferation, and apoptosis.

Classification and mechanism: They include natural retinoids such as retinol, retinaldehyde, and retinoic acids (all-trans-RA, 9-cis-RA), as well as synthetic retinoids such as tretinoin, adapalene, isotretinoin, acitretin, alitretinoin, and bexarotene (a rexinoid). Mechanistically, many act as agonists of RARs and RXRs, forming heterodimers that bind retinoic acid response elements to regulate gene expression; some influence retinoid metabolism or signaling in RAR- or RXR-independent ways.

Clinical uses: In dermatology, retinoid agents treat acne, photoaging, and psoriasis; topical agents reduce keratinization while systemic retinoids can improve severe nodular acne. In oncology, all-trans retinoic acid is a cornerstone for acute promyelocytic leukemia; rexinoids and other retinoids are explored in other cancers and in combination therapies.

Safety and regulation: Retinoids can be teratogenic; systemic therapy requires monitoring and, for some products, enrollment in regulatory programs (for example, isotretinoin programs to prevent fetal exposure). Common adverse effects include mucocutaneous dryness, cheilitis, photosensitivity, and hepatotoxicity or lipid abnormalities with systemic agents; long-term use can affect bone turnover. Patients should avoid excessive sun exposure and adhere to medical supervision.

Research and future directions: Ongoing work includes developing selective RAR or RXR modulators with improved safety, topical formulations, and combination regimens to minimize systemic exposure. See also retinoids, retinoic acid receptors, rexinoids.