About Isotretinoin Vitamin A isomer, Retinoic Acid Derivative, Anti-acne. Mechanism of Action of Isotretinoin Isotretinoin is a 13-cis-retinoic acid and is used in the treatment of severe nodulocystic acne. Isotretinoin decreases sebocyte number and reduces sebum synthesis and therefore used in the treatment of acne.It reduces sebaceous gland size and inhibits sebaceous gland differentiation. Isotretinoin reduces the production of sebum and shrinks the sebaceous glands. It stabilises keratinization and prevents comedones formation. It alters DNA transcription Interactions for Isotretinoin Alcohol: Etretinate formed in presence of alcohol. Antibacterials: Possible increased risk of benign intracranial hypertension with tetracyclines. Warfarin: Possible reduction in anticoagulant effect. Antiepileptics: Plasma concentration of carbamazepine may be reduced. Cytotoxic drugs: Plasma concentration of methotrexate may be increased.