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.
Adult: As 0.05% gel: Apply sparingly once or twice daily. Effect is observed w/in 6-8 wk of treatment.
Severe: Reduce initial dose (e.g. 10 mg daily), then gradually increase to 1 mg/kg as necessary.
Should be taken with food.
Hypervitaminosis A, hyperlipidaemia. Hepatic impairment. Pregnancy and lactation. Concomitant admin of tetracycylines.
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.
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. Potentially Fatal: Haemorrhagic pancreatitis, severe skin reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis).
Avoid exposure to natural or artificial sunlight. Avoid blood donation during therapy and for at least 1 mth following drug discontinuation. This drug may cause dizziness, drowsiness and visual disturbances, if affected, do not drive or operate machinery.
Additive adverse effects w/ vit A or its derivatives. Decreased efficacy of microdosed progesterone (use 2 forms of contraception).Increased risk of local irritation w/ topical keratolytic or exfoliative anti-acne agents. Oxidising agents (e.g. benzoyl peroxide) may reduce the efficacy of topical isotretinoin. Potentially Fatal: Development of benign intracranial HTN w/ tetracycline.
Increased bioavailability w/ food or milk.
Description: 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. Pharmacokinetics: Absorption: Absorbed from the GI tract (oral); minimal systemic absorption (topical). Increased bioavailability if taken w/ milk or food. Time to peak plasma concentrations: 1-4 hr (oral). Distribution: Protein-binding: 99.9%, mainly to albumin. Metabolism: Metabolised in the liver to 4-oxo-isotretinoin by CYP isoenzymes (mainly CYP2C8, CYP2C9, CYP3A4 and CYP2B6); also undergoes some isomerisation to tretinoin. Excretion: Via urine as metabolites and faeces, mainly as unchanged drug. Terminal elimination half-life: 21 hr (isotretinoin); 21-24 hr (4-oxo metabolite).
D10BA01 - isotretinoin ; Belongs to the class of systemic retinoid preparations used in the treatment of acne. D10AD04 - isotretinoin ; Belongs to the class of topical retinoid preparations used in the treatment of acne.
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