The oral LD50 of isotretinoin is greater than 4000 mg/kg in rats and mice ( > 600 times the recommended clinical dose of 1 mg/kg/day after normalization of the rat dose for total body surface area and > 300 times the recommended clinical dose of 1 mg/kg/day after normalization of the mouse dose for total body surface area) and is approximately 1960 mg/kg in rabbits (653 times the recommended clinical dose of 1 mg/kg/day after normalization for total body surface area). In humans, overdosage has been associated with vomiting, facial flushing, cheilosis, abdominal pain, headache, dizziness, and ataxia. These symptoms quickly resolve without apparent residual effects.
Zenatane causes serious birth defects at any dosage (see BOXED CONTRAINDICATIONS AND WARNINGS). Female patients of childbearing potential who present with isotretinoin overdose must be evaluated for pregnancy. Patients who are pregnant should receive counseling about the risks to the fetus, as described in the Boxed CONTRAINDICATIONS AND WARNINGS. Non-pregnant patients must be warned to avoid pregnancy for at least one month and receive contraceptive counseling as described in PRECAUTIONS. Educational materials for such patients can be obtained by calling the manufacturer. Because an overdose would be expected to result in higher levels of isotretinoin in semen than found during a normal treatment course, male patients should use a condom, or avoid reproductive sexual activity with a female patient who is or might become pregnant, for one month after the overdose. All patients with isotretinoin overdose should not donate blood for at least one month.
Category X. See BOXED CONTRAINDICATIONS AND WARNINGS.
Zenatane is contraindicated in patients who are hypersensitive to this medication or to any of its components. (see PRECAUTIONS: Hypersensitivity).
Last reviewed on RxList: 4/15/2013
This monograph has been modified to include the generic and brand name in many instances.
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