SSAT063- Pharmacokinetics of Efavirenz 400 mg Once Daily During Pregnancy in HIV-1 Infected Women

The purpose of the study is to measure the drug levels in your blood and to find out whether a reduced dose (400mg) of the anti-HIV medication Efavirenz is safe when taken during pregnancy. The study will recruit HIV infected women who take Efavirenz as part of their anti-hiv treatment and who are pregnant. Efavirenz has been shown to be safe in pregnancy and at the standard dose that everybody takes of 600mg once a day, it shows levels that are enough to treat HIV and give birth to a HIV negative baby. Efavirenz at a dose of 400mg once daily works against HIV too but this dose has not been given to HIV positive pregnant women. People with HIV may benefit from using a dose of efavirenz of 400mg instead of 600mg, as lower drug doses could have fewer side effects and be tolerated better. Dose reduction would also make the drug cheaper. This would allow more people to be treated and free up money for other important work in the fight against HIV such as education and prevention programs. However, it is not known whether 400mg of Efavirenz works as well as 600mg of Efavirenz during pregnancy and this is why the investigators are conducting this study, which aims to measure the amount of Efavirenz 400mg in HIV pregnant women's bodies when they are taking 400mg of Efavirenz once a day.