Isotretinoin

# Isotretinoin ## Overview - **Classification**: Systemic Retinoid (Vitamin A derivative) - **Mechanism**: Reduces sebaceous gland size and sebum production, normalizes follicular keratinization, and has anti-inflammatory properties. ## Primary Indications 1. **Severe recalcitrant nodular acne**: unresponsive to conventional therapies, including systemic antibiotics. 2. **Acne with significant psychological distress**: or risk of permanent scarring. ## Adult Dosing ### Standard Dosing **Severe Recalcitrant Nodular Acne** - **Dose**: Start with **0.5 mg/kg/day** - **Frequency**: Once or twice daily - **Route**: Oral - **Duration**: Typically **15-20 weeks** or until cumulative dose of **120-150 mg/kg** is reached. - **Dose escalation**: May increase to **1 mg/kg/day** as tolerated. - **Maximum Dose**: **2 mg/kg/day** for very severe disease or truncal acne; generally no more than **1 mg/kg/day** is tolerated. ### Dose Adjustments - **Renal Impairment**: Use with extreme caution; **start at lower dose** (**10 mg/day**) and monitor closely. - **Hepatic Impairment**: Generally **contraindicated** due to risk of hepatotoxicity. - **Elderly Patients**: Not well studied; use with caution due to potential comorbidities. ## Pediatric Dosing ### Neonates (0-28 days) - **Not indicated**. - **Special Notes**: Safety and efficacy not established. ### Infants (1-12 months) - **Not indicated**. - **Special Notes**: Safety and efficacy not established. ### Children (1-12 years) - **Indication**: Severe recalcitrant nodular acne, only if deemed medically necessary and after puberty. - **Dose**: **0.5 mg/kg/day** - **Frequency**: Once or twice daily - **Maximum**: Can increase to **1 mg/kg/day** if tolerated. - **Special Notes**: Close monitoring for growth plates and adverse effects required. ### Adolescents (13-18 years) - **Indication**: Severe recalcitrant nodular acne. - **Dose**: **0.5 mg/kg/day** initially. - **Frequency**: Once or twice daily. - **Maximum**: Can increase to **1 mg/kg/day** as tolerated. Max cumulative dose **120-150 mg/kg**. - **Special Notes**: Same iPLEDGE requirements as adults for females of childbearing potential. ## Safety Information ### Contraindications - **Absolute**: **Pregnancy** (Category X), known hypersensitivity to retinoids. - **Absolute**: Females of childbearing potential not adhering to iPLEDGE program requirements. - **Absolute**: Breastfeeding. - **Relative**: Concomitant use with tetracyclines (risk of pseudotumor cerebri). ### Common Adverse Effects - **Very Common (>10%)**: Cheilitis (dry lips), dry skin, dry eyes, epistaxis, elevated triglycerides, arthralgia/myalgia. - **Common (1-10%)**: Photosensitivity, headache, rash, pruritus, elevated LFTs. - **Serious but Rare**: Psychiatric effects (depression, suicidal ideation), pseudotumor cerebri (benign intracranial hypertension), inflammatory bowel disease (controversial link), severe allergic reactions. ### Key Drug Interactions - **Tetracyclines**: Increased risk of pseudotumor cerebri (benign intracranial hypertension). - **Vitamin A Supplements**: Increased risk of hypervitaminosis A toxicity (e.g., bone changes, headache). - **Progestin-Only Contraceptives**: May decrease efficacy; two forms of contraception required for females. - **Alcohol**: May exacerbate liver enzyme elevations and hypertriglyceridemia. ## Monitoring & Follow-up - **Before Treatment**: Two negative pregnancy tests (females), baseline LFTs, fasting lipid panel (triglycerides, cholesterol), CBC. - **During Treatment**: Monthly pregnancy tests (females), monthly LFTs and fasting lipid panel (adjust frequency based on results). - **Clinical Signs**: Monitor for mood changes, vision changes, severe headache, muscle/joint pain, GI symptoms, skin infections. ## Clinical Pearls - 💡 **Take with Food**: Administer with a high-fat meal to significantly improve absorption. - 💡 **iPLEDGE Program**: Strict adherence is mandatory for all patients, especially females of childbearing potential (two forms of contraception required). - 💡 **Skin Care**: Counsel patients on aggressive moisturizing for skin/lips, use of artificial tears, and broad-spectrum sunscreen. - 💡 **Avoid Waxing**: Skin becomes fragile; avoid waxing, dermabrasion, or laser resurfacing during and for 6 months post-treatment. - 💡 **Donation Restrictions**: Patients should not donate blood during treatment and for 1 month after discontinuation. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.