Overview
DESCRIPTION Isotretinoin, a retinoid, is available as isotretinoin capsules in 10-mg, 20-mg, 30-mg and 40-mg soft gelatin capsules for oral administration. Each capsule contains yellow wax, butylated hydroxyanisole, edetate disodium, hydrogenated vegetable oil, tocopherol, and soybean oil.
Mechanism of Action
CLINICAL PHARMACOLOGY Isotretinoin is a retinoid, which when administered in pharmacologic dosages of 0.5 to 1 mg/kg/day (see DOSAGE AND ADMINISTRATION ), inhibits sebaceous gland function and keratinization. The exact mechanism of action of isotretinoin is unknown. Nodular Acne Clinical improvement in nodular acne patients occurs in association with a reduction in sebum secretion. The decrease in sebum secretion is temporary and is related to the dose and duration of treatment with isotretinoin capsules, and reflects a reduction in sebaceous gland size and an inhibition of sebaceous gland differentiation. 1 Pharmacokinetics Absorption Due to its high lipophilicity, oral absorption of isotretinoin is enhanced when given with a high-fat meal.
Indications
- INDICATIONS AND USAGE Severe Recalcitrant Nodular Acne Isotretinoin capsules are 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. "Severe," by definition, 2 means "many" as opposed to "few or several" nodules. Because of significant adverse effects associated with its use, isotretinoin capsules should be reserved for patients with severe nodular acne who are unresponsive to conventional therapy, including systemic antibiotics.
Common Doses
- 1 mg
- 2 mg
- 0.5 mg
Dosage
DOSAGE AND ADMINISTRATION Isotretinoin capsules should be administered with a meal (see PRECAUTIONS: Information for Patients ). The recommended dosage range for isotretinoin capsules are 0.5 to 1 mg/kg/day given in two divided doses with food for 15 to 20 weeks. In studies comparing 0.1, 0.5, and 1 mg/kg/day 8 , it was found that all dosages provided initial clearing of disease, but there was a greater need for retreatment with the lower dosages.
Black Box Warning
CONTRAINDICATIONS AND WARNINGS Isotretinoin capsules must not be used by patients who are or may become pregnant. There is an extremely high risk that life-threatening birth defects will result if pregnancy occurs while taking isotretinoin capsules in any amount, even for short periods of time. Potentially any fetus exposed during pregnancy can be affected. There are no accurate means of determining whether an exposed fetus has been affected.
Contraindications
- CONTRAINDICATIONS Pregnancy Category X See Boxed CONTRAINDICATIONS AND WARNINGS . Allergic Reactions Isotretinoin capsules are contraindicated in patients who are hypersensitive to this medication or to any of its components (see PRECAUTIONS: Hypersensitivity ).
Side Effects
- ADVERSE REACTIONS Clinical Trials and Postmarketing Surveillance The adverse reactions listed below reflect the experience from investigational studies of isotretinoin , and the postmarketing experience. The relationship of some of these events to isotretinoin therapy is unknown. Many of the side effects and adverse reactions seen in patients receiving isotretinoin are similar to those described in patients taking very high doses of vitamin A (dryness of the skin and mucous membranes, e.g. of the lips, nasal passage, and eyes).
Interactions
- Drug Interactions Vitamin A: Because of the relationship of isotretinoin capsules to vitamin A, patients should be advised against taking vitamin supplements containing vitamin A to avoid additive toxic effects. Tetracyclines: Concomitant treatment with isotretinoin capsules and tetracyclines should be avoided because isotretinoin capsules use has been associated with a number of cases of pseudotumor cerebri (benign intracranial hypertension), some of which involved concomitant use of tetracyclines.