Indications
Isotretinoin is indicated for the treatment of severe recalcitrant nodular acne. Nodules are inflammatory lesions with a diameter of 5 mm or greater. The nodules may become suppurative or hemorrhagic. Because of significant adverse effects associated with its use, Isotretinoin should be reserved for patients with severe nodular acne who are unresponsive to conventional therapy, including systemic antibiotics. In addition, Isotretinoin is indicated only for those female patients who are not pregnant, because Isotretinoin can cause severe birth defectsA single course of therapy for 15 to 20 weeks has been shown to result in complete and prolonged remission of disease in many patients. If a second course of therapy is needed, it should not be initiated until at least 8 weeks after completion of the first course, because experience has shown that patients may continue to improve while off Isotretinoin . The optimal interval before re-treatment has not been defined for patients who have not completed skeletal growth
Drug Class
Oral retinoids for Acne
Pharmacology
Isotretinoin is a synthetic retinoid which reduces sebaceous gland size and inhibits sebum production. It also regulates cell proliferation and differentiation and has dermal anti-inflammatory effect.
Dosage
Oral-Adult: Initially, 0.5 mg/kg daily in single or 2 divided doses, increased to 1 mg/kg daily if necessary. Usual duration of treatment: 16-24 wk. May repeat treatment course after at least 8 wk if relapse after first course.Child: ≥12 yr Same as adult dose.Topical: Apply Isotretinoin 0.05% gel cautiously over the affected area once or twice daily. Patients should be advised that 6-8 weeks of treatment may be required before a therapeuticeffect is observed. The safety and efficacy of Isotretinoin have not been established in children since acne vulgaris rarely present in this age group. There are no specific recommendations for use in the elderly. Acne vulgaris does not present in the elderly.
Interaction
Additive adverse effects with vit A or its derivatives. Decreased efficacy of microdosed progesterone (use 2 forms of contraception).Increased risk of local irritation with topical keratolytic or exfoliative anti-acne agents. Oxidising agents (e.g. benzoyl peroxide) may reduce the efficacy of topical isotretinoin.
Contraindications
Hypervitaminosis A, hyperlipidaemia. Hepatic impairment. Pregnancy and lactation. Concomitant admin of tetracycylines.
Side Effects
Erythema, skin exfoliation, stinging sensation, pruritus, irritation, tenderness, dry skin, hirsutism, photosensitivity, skin pigmentation, paronychia, nail dystrophy, pyogenic granuloma, increased sweating, corneal opacities, visual disturbances, headache, nausea and vomiting, arthralgia, myalgia, back pain, intracranial HTN, hyperostosis and calcinosis. Elevation of serum triglycerides, LFTs, ESR and blood glucose. Mood changes, psychotic symptoms, depression and suicidal behaviour.
Precautions
Women of childbearing potential; anorexia nervosa. History of photoallergy, psychiatric disorder (e.g. depression); pre-existing or predisposition to hypertriglyceridaemia (e.g. DM, obesity or increased alcohol intake). Genetic predisposition for age-related osteoporosis, history of childhood osteoporosis, osteomalacia or other bone metabolism disorders. Not intended for the treatment of prepubertal acne. Severe renal impairment.
Pediatric Use
Renal Impairment: Oral: Severe: Reduce initial dose (e.g. 10 mg daily), then gradually increase to 1 mg/kg as necessary.Hepatic Impairment: Oral: Contraindicated.
Storage Condition
Store between 20-25° C. Protect from light.