DRUG INTERACTIONS
Drug Interactions: Concomitant use of SUSTIVA and St. John’s wort (Hypericum perforatum) or St. John’s wort-containing products is not recommended. Coadministration of non-nucleoside reverse transcriptase inhibitors (NNRTIs), including SUSTIVA, with St. John’s wort is expected to substantially decrease NNRTI concentrations and may result in suboptimal levels of efavirenz and lead to loss of virologic response and possible resistance to efavirenz or to the class of NNRTIs.
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OVERDOSAGE
Some patients accidentally taking 600 mg twice daily have reported increased nervous system symptoms. One patient experienced involuntary muscle contractions.
Treatment of overdose with SUSTIVA (efavirenz) should consist of general supportive measures, including monitoring of vital signs and observation of the patient’s clinical status. Administration of activated charcoal may be used to aid removal of unabsorbed drug. There is no specific antidote for overdose with SUSTIVA. Since efavirenz is highly protein bound, dialysis is unlikely to significantly remove the drug from blood.
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CONTRAINDICATIONS
SUSTIVA (efavirenz) is contraindicated in patients with clinically significant hypersensitivity to any of its components.
SUSTIVA should not be administered concurrently with astemizole, bepridil, cisapride, midazolam, pimozide, triazolam, or ergot derivatives because competition for CYP3A4 by efavirenz could result in inhibition of metabolism of these drugs and create the potential for serious and/or life-threatening adverse events (eg, cardiac arrhythmias, prolonged sedation, or respiratory depression). SUSTIVA should not be administered concurrently with standard doses of voriconazole because SUSTIVA significantly decreases voriconazole plasma concentrations. Adjusted doses of voriconazole and efavirenz may be administered concomitantly (see CLINICAL PHARMACOLOGY, Tables 1 and 2; PRECAUTIONS: Drug Interactions, Table 5; and DOSAGE AND ADMINISTRATION: Dosage Adjustment).
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