HIV This Week

Laureillard D, Prak N, Fernandez M, Ngeth C, Moeung S, Riel V, Chhneang V, Song S, Quillet C and Piketty C. Efavirenz replacement by immediate full-dose nevirapine is safe in HIV-1-infected patients in Cambodia. HIV Medicine 2008; DOI: 10.1111/j.1468-1293.2008.00597.x

Efavirenz is used for the antiretroviral treatment of HIV/tuberculosis-coinfected patients in developing countries. A switch to nevirapine is regularly carried out because of the cost and side effects of efavirenz. Pharmacokinetic studies suggested that nevirapine should be initiated at full dose when used as a substitute for efavirenz. The aim of this study was to measure the cumulative incidence of adverse events (AEs) related to nevirapine in patients switched from efavirenz to immediate full-dose nevirapine (FDN). In 2001 an antiretroviral treatment programme was initiated with the first-line regimen stavudine, lamivudine and efavirenz. In 2003, the fixed-dose combination of stavudine, lamivudine and nevirapine was recommended. Thus, first-line therapy was changed and FDN was initiated when patients were switched from efavirenz to nevirapine. Between April and December 2004, 394 patients were switched from efavirenz to full does nevirapine. The cumulative incidence of AEs related to nevirapine was 13.2% [95% confidence interval (CI) 10.2– 16.7] and that of severe AEs was 8.9% (95% CI 6.5–11.9). In women the incidence of AEs was 17.6% (95% CI 12.1–24.3) and that of severe AEs was 12.2% (95% CI 7.7–18.2). Laureillard et al’s results indicate that a full dose nevirapine switch from efavirenz does not appear to result in more adverse events than when nevirapine is initiated with escalating doses. These data are particularly relevant in resource-limited settings.

Editors’ note: Efavirenz is more expensive than nevirapine, should not be used in women of childbearing potential, and has a long plasma half-life. This is the first study evaluating a switch from an efavirenz-containing regimen to a nevirapine-containing one where full-dose nevirapine rather than escalating doses of nevirapine were used to overcome efavirenz competition for cytochrome CYP 3A4 and reduce the risk of nevirapine resistance. It is encouraging that increased adverse effects were not seen .