Isotretinoin

Isotretinoin is a retinoid that targets severe forms of acne by modulating skin cell growth and sebum production.

• Severe nodular acne: reduces inflammatory lesions and prevents formation of new nodules.
• Acne vulgaris: improves overall skin clearance in patients with resistant or extensive disease.
• Cystic acne: decreases cyst formation and promotes faster lesion resolution.

• Isotretinoin acts by binding to nuclear retinoic acid receptors, leading to decreased transcription of genes involved in sebaceous gland proliferation and sebum synthesis. It normalizes follicular keratinization, reduces inflammatory cytokine production, and exerts anti‑inflammatory effects, collectively resulting in reduced acne lesion formation. Additionally, isotretinoin down‑regulates the activity of matrix metalloproteinases and modulates immune cell infiltration within the pilosebaceous unit, further contributing to its therapeutic effect.

Isotretinoin may cause a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Dry skin and lips: excessive xerosis and cheilitis.
• Elevated liver enzymes: mild transaminase increase.
• Skin sensitivity: heightened photosensitivity and irritation.
• Headache: mild to moderate tension‑type headaches.

Serious or Rare Side Effects

• Teratogenicity: severe birth defects if exposure occurs during pregnancy.
• Depression and suicidal ideation: potential mood disturbances requiring monitoring.
• Inflammatory bowel disease: rare onset or exacerbation of Crohn’s disease.
• Hypertriglyceridemia and pancreatitis: significant lipid elevation leading to pancreatic inflammation.

Before initiating isotretinoin therapy, several precautions should be observed to ensure patient safety.

• Pregnancy: contraindicated due to high teratogenic risk; effective contraception required.
• Liver function: monitor transaminases before and during treatment.
• Lipid profile: assess serum triglycerides and cholesterol regularly.
• Mood changes: screen for depression, anxiety, or suicidal thoughts throughout therapy.
• Vitamin A intake: avoid concurrent high‑dose vitamin A supplements.
• Store at ambient temperature: keep below 25 °C in original packaging, protect from moisture and light.

Isotretinoin can interact with other medicines, altering its efficacy or increasing toxicity.

Major Interactions (Avoid)

• Tetracyclines: combined use may increase risk of intracranial hypertension.
• Vitamin A supplements: additive retinoid toxicity may occur.
• Other systemic retinoids: cumulative toxicity can lead to severe adverse effects.

Moderate Interactions (Monitor Closely)

• Anticonvulsants (e.g., phenytoin, carbamazepine): enzyme induction may reduce isotretinoin levels.
• Corticosteroids: concurrent use may heighten risk of mood disturbances and skin fragility.
• Azole antifungals (e.g., ketoconazole): may increase isotretinoin plasma concentrations.