The use of nevirapine to prevent mother-to-child transmission of HIV has been controversial. Claims of high rates of toxicity have not been confirmed in clinical trials or extensive programme experience of use of the regimen. Whilst single-dose nevirapine can reduce transmission rates to approximately 10-15%, this can be halved by the addition of single-dose nevirapine to short-course regimens of zidovudine. The selection of resistant virus is reported in 20-50% of mothers and 50% of infants following one dose of nevirapine, although the impact of this on future treatment options is not fully understood. An increased risk of severe hepatotoxicity has been reported with long-term nevirapine-containing triple-therapy treatment regimens in women with CD4+ counts > 250 cells/mm3.