Isotretinoin is a medication used for the treatment of severe acne. It is sometimes used in prevention of certain skin cancers. It is a retinoid, meaning it derives from vitamin A and is found in small quantities naturally in the body. Isotretinoin binds to and activates nuclear retinoic acid receptors (RAR), thereby regulating cell proliferation and differentiation. This agent also exhibits immunomodulatory and anti-inflammatory responses and inhibits ornithine decarboxylase, thereby decreasing polyamine synthesis and keratinization.
Humans and other mammals
For the treatment of severe recalcitrant nodular acne
Isotretinoin, a retinoid, is indicated in the treatment of severe recalcitrant nodular acne. Nodules are inflammatory lesions with a diameter of 5 mm or greater. The nodules may become suppurative or hemorrhagic. "Severe," by definition, means "many" as opposed to "few or several" nodules. Clinical improvement in nodular acne patients occurs in association with a reduction in sebum secretion. The decrease in sebum secretion is temporary and is related to the dose and duration of treatment with Accutane, and reflects a reduction in sebaceous gland size and an inhibition of sebaceous gland differentiation.
Mechanism of action
Isotretinoin noticeably reduces the production of sebum and shrinks the sebaceous glands. It stabilises keratinization and prevents comedones from forming. It also reduces inflammation in moderate-severe inflammatory acne. The exact mechanism of action is unknown, however it is known that it alters DNA transcription.