Efavirenz replacement by immediate full-dose nevirapine is safe in HIV-1-infected patients in Cambodia

Background 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. Objectives 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). Methods 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. Results Between April and December 2004, 394 patients were switched from efavirenz to FDN. 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). Conclusions Our results indicate that an FDN switch from efavirenz does not appear to result in more AEs than when nevirapine is initiated with escalating doses. These data are particularly relevant in resource-limited settings.