Isotretinoin, Oral
Anti-acne Preps · Vitamin A derivative
Indications
Cystic and conglobate acne, severe acne unresponsive to antibiotic therapy.
Dosage
Adults: Initially 0.5 mg/kg body wt. daily as a single dose or in two divided doses with food for 4 wk. Adjust according to response in range 0.1-1 mg/kg body wt. daily for a further 8-12 wk. Repeat courses are not normally recommended. Max, 150 mg/kg per course. Children: Not recommended.
Adverse Effects
Dryness, erosion of mucosa. Monitor for keratitis with dry eye. Alopecia. Rise in liver enzymes and serum triglycerides (risk of fatal pancreatitis). Nausea, headache, drowsiness, sweating, mood changes, neurological disorders, psychiatric reactions, seizures, menstrual irregularities, myalgia, arthralgia. Reversible haematuria and proteinuria. Occasionally, hearing loss, allergic vasculitis, thrombocytopenia, visual disturbances (warn patient as can be sudden; refer patients for ophthalmological examination and consider withdrawal). Rarely, facial hyperpigmentation, hirsutism, acne fulminans, lymphadenopathy, blood dyscrasias, increased transaminases, triglycerides, cholesterol and blood glucose. Reports of benign intracranial hypertension (discontinue), decreased night vision.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Contraindicated in pregnancy. Lactation: Caution advised or effect undetermined. Contraindications: Renal or hepatic impairment, hyperlipidaemia, hypervitaminosis A. Soya or peanut allergy. Pregnancy (teratogenic), women of childbearing potential unless all conditions of pregnancy prevention programme are met. Precautions: Prescription must be written by a named dermatologist. Exclude pregnancy before starting treatment; effective contraceptive measures must be taken by women of child-bearing potential for 1 mth before, during and for at least 4 wks after therapy. Monitor liver function before starting treatment, 1 mth later and then at 3 mth intervals; reduce dose or discontinue if transaminase levels exceed normal. Monitor fasting serum lipids before starting treatment, 1 mth later and then at end of treatment; discontinue if hypertriglyceridaemia is uncontrolled or…
Interactions
High dose vitamin A, tetracyclines, keratolytics, exfoliative anti-acne agents.
Advice to Patient
Take with meals. Capsules may be chewed and swallowed, swallowed or opened with a large needle and contents sprinkled on applesauce or icecream. Take whole capsule with a full glass of liquid. Contact prescriber if there are acute changes in vision, changes in hearing, rectal bleeding, stomach cramps or unrelieved diarrhoea and discontinue treatment. Reduce intake of vitamin A, avoid other products containing vitamin A and increased exercise during therapy. Avoid or reduce intake of alcohol during therapy. Severe acne may occur during first week of therapy. There may be headache, loss of night vision, lethargy or disturbances in vision. Avoid direct sunlight. Wear sunscreen, eyewear and protective clothing to prevent photosensitivity. Wear normal glasses to prevent eye irritation. Avoid wax epilation and skin resurfacing procedures during therapy and for atleast 6 months thereafter…
Pharmacokinetics
Note: Pharmacokinetic parameters in adolescents (12-15 yrs) are similar to adults. Absorption: Enhanced with a high-fat meal. Protein binding: 99%-100%; primarily albumin Metabolism: Hepatic. Half-life elimination: Terminal: Parent drug: 21 hrs. Metabolite: 21-24 hrs. Time to peak, serum: 3-5 hrs. Excretion: Urine and faeces (equal amounts).
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
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