The United States Food and Drug Administration (FDA) has approved revisions to the package insert for Sustiva (efavirenz) capsules and tablets to include new information on potential birth defects, liver toxicity, and drug interactions.

Sustiva, which is an antiretroviral drug made by Bristol-Myers Squibb, is approved by the FDA for use in combination with other antiretroviral agents in HIV-positive adults and children older than three years of age.

Sustiva is classified as a Pregnancy Category D drug, indicating there is evidence it can cause birth defects.

The new label has updated information on fetal harm, including neural tube defects (birth defects of the brain and spinal cord), that can occur if Sustiva is taken during the first trimester of pregnancy.

The Antiretroviral Pregnancy Registry, which monitors fetal outcomes of pregnant women exposed to Sustiva, reported birth defects in about three percent of live births involving first-trimester exposure to Sustiva, and in just over 3.5 percent of live births involving second/third-trimester exposure.

Additionally, the revised label warns of potential liver toxicity in people taking Sustiva.

Although most cases of serious liver problems occurred in patients with pre-existing liver dysfunction, a few cases occurred in patients without any pre-existing liver disease.

The liver problems encountered sometimes culminated in transplantation or death.

As a result, the FDA recommends considering liver enzyme monitoring in Sustiva patients, regardless of whether they have pre-existing liver dysfunction or not.

The label also cautions that Noxafil (posaconazole), which is used to treat Candida and other yeast infections, only be taken in combination with Sustiva if the benefit of the treatment offsets the risks. Sustiva can reduce the amount of Noxafil in the blood, making it less effective for treating infections.

Finally, the FDA warns that if Sustiva is taken with Selzentry (maraviroc), changes in the dose of one of the drugs may be necessary.

For more information, please see the FDA Web site.