Alltransretinoic

All-trans retinoic acid (ATRA), also known as alltransretinoic acid, is the all-trans isomer of retinoic acid and a retinoid that is the active metabolite of vitamin A (retinol). It functions as a ligand for nuclear retinoic acid receptors, regulating transcription of genes involved in cell differentiation, development, and maintenance of tissues.

In medicine, ATRA is used as differentiation therapy for acute promyelocytic leukemia (APL), where it promotes the maturation of malignant promyelocytes and can induce remission when used with other treatments such as arsenic trioxide or chemotherapy. It is also applied topically for dermatologic conditions such as acne vulgaris and signs of photoaging, in formulations that promote epidermal turnover and collagen remodeling.

Mechanism of action centers on binding to retinoic acid receptors (RARα, RARβ, RARγ), which form heterodimers with retinoid X receptors (RXR) to regulate transcription of retinoic acid–responsive genes. In APL, a PML-RARα fusion protein blocks differentiation; ATRA relieves this block, enabling leukemic cells to differentiate and ultimately die or mature.

Safety and adverse effects include teratogenicity, making pregnancy contraindicated during treatment. Common side effects are mucocutaneous dryness, cheilitis, headaches, and hepatotoxicity. A potentially life-threatening retinoic acid syndrome (differentiation syndrome) can occur during treatment and requires prompt recognition and management.

Formulations and administration vary by indication: systemic therapy uses oral capsules for APL, while dermatologic use employs topical gels or creams. The pharmacokinetic profile features a relatively short half-life, necessitating regular dosing and clinical monitoring for adverse events.