Isonoin 20 Soft Gelatin 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 antibiotics and topical agents. Isotretinoin acts 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 of acne. The soft gelatin capsule formulation ensures optimal bioavailability and ease of administration. Isonoin 20 should be used under strict medical supervision due to its potential for serious adverse effects, including teratogenicity, hepatotoxicity, and lipid abnormalities. Prior to initiation, baseline liver function tests, lipid profile, and pregnancy testing in women of childbearing potential are mandatory. Regular monitoring during therapy is essential to detect and manage side effects promptly. Patients must adhere to contraceptive measures throughout treatment and for a specified period after discontinuation to prevent fetal exposure. Common adverse reactions include dry skin, cheilitis, and photosensitivity. Isonoin 20 is contraindicated in pregnancy, hypersensitivity to isotretinoin, and patients with hepatic impairment or hyperlipidemia. This medication should be prescribed by dermatologists experienced in isotretinoin therapy to ensure safe and effective use.