Isotretinoína Mer (Isotretinoin)

Isotretinoin is a retinoid used in dermatology to treat severe forms of acne that are resistant to conventional therapy.

• Severe recalcitrant nodular acne: markedly reduces inflammatory lesions and prevents formation of new nodules.
• Acne vulgaris unresponsive to other therapies: improves overall skin clearance and reduces scarring risk.
• Persistent cystic acne: diminishes cyst formation and promotes long‑term remission.

• Isotretinoin binds to nuclear retinoic acid receptors, modulating gene expression that leads to decreased sebaceous gland size and reduced sebum production. It also normalizes follicular keratinization and exerts anti‑inflammatory effects, thereby limiting the proliferation of Cutibacterium acnes and the formation of acne lesions.

Isotretinoin may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Dry skin and mucous membranes: including cheilitis and xerosis.
• Photosensitivity: increased susceptibility to sunburn.
• Elevated liver enzymes: mild transaminase rise.
• Hypertriglyceridemia: rise in serum triglyceride levels.
• Musculoskeletal discomfort: joint or muscle aches.
• Mood changes: irritability or mild depressive symptoms.

Serious or Rare Side Effects

• Severe depression or suicidal ideation.
• Pancreatitis: associated with marked hypertriglyceridemia.
• Inflammatory bowel disease exacerbation.
• Teratogenicity: severe fetal malformations if exposure occurs during pregnancy.
• Pseudotumor cerebri: increased intracranial pressure.
• Severe hepatotoxicity: significant liver enzyme elevation.

Isotretinoin requires careful monitoring and patient education due to its potency and risk profile.

• Pregnancy: contraindicated; ensure effective contraception and negative pregnancy test before initiation.
• Breastfeeding: avoid use as drug is excreted in milk and may harm the infant.
• Liver function: monitor transaminases and bilirubin regularly.
• Lipid profile: check serum triglycerides and cholesterol at baseline and during therapy.
• Mood monitoring: assess for depressive symptoms or suicidal thoughts throughout treatment.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture and direct sunlight.

Isotretinoin can interact with several medications, altering efficacy or increasing toxicity.

Major Interactions (Avoid)

• Vitamin A supplements: additive toxicity leading to severe hypervitaminosis A.
• Tetracycline antibiotics: increased risk of intracranial hypertension (pseudotumor cerebri).
• Systemic corticosteroids: heightened risk of psychiatric adverse events.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: possible reduction in contraceptive effectiveness; additional barrier methods recommended.
• Anticoagulants (e.g., warfarin): potential alteration of INR; monitor coagulation parameters.
• Lipid‑lowering agents (e.g., fibrates): may exacerbate triglyceride elevations; check lipid levels regularly.