Isoin 20 Capsule contains isotretinoin 20 mg, a retinoid derivative primarily indicated for the treatment of severe recalcitrant nodular acne that is unresponsive to conventional therapies such as systemic antibiotics. Isotretinoin works by reducing sebaceous gland size and sebum production, inhibiting the growth of acne-causing bacteria, and exerting anti-inflammatory effects, thereby addressing multiple pathogenic factors involved in acne development. This medication is typically prescribed under strict medical supervision due to its potent efficacy and potential for serious adverse effects. Isoin 20 Capsule should be administered orally with food to enhance absorption, and the dosage regimen is individualized based on patient response and tolerability. Common side effects include dry skin, cheilitis, and photosensitivity, while more severe risks involve teratogenicity, hepatotoxicity, hyperlipidemia, and mood alterations. Therefore, regular monitoring of liver function tests, lipid profile, and pregnancy status in females of childbearing potential is essential during therapy. Patients are advised to avoid vitamin A supplementation and to use effective contraception throughout treatment and for a specified period afterward. Isoin 20 Capsule is contraindicated in pregnancy and should be used cautiously in patients with pre-existing liver or lipid disorders. This medication offers a valuable option for patients with severe acne unresponsive to other treatments, improving clinical outcomes and quality of life when used appropriately.