ORIGINAL RESEARCH Efavirenz replacement by immediate full-dose nevirapine is safe in HIV-1-infected patients in Cambodia D Laureillard, 1,3 N Prak, 2 M Fernandez, 2,3 C Ngeth, 2 S Moeung, 2 V Riel, 2 V Chhneang, 2 S Song, 2 C Quillet 2,3 and C Piketty 1 1 APHP, Department of Immunology, Georges Pompidou European Hospital, Paris, France, 2 Infectious Diseases Department, Khmero-Sovietic Friendship Hospital, Phnom Penh, Cambodia, and 3 Cambodian Heath Committee, Phnom Penh, 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. Keywords: Cambodia, efavirenz, HIV infection, nevirapine Received: 6 September 2007, accepted 11 April 2008 Introduction The efficacy and safety of nonnucleoside reverse tran- scriptase inhibitor (NNRTI)-based regimens have been demonstrated in the treatment of HIV-1-infected patients [1–3]. The World Health Organization recommends the use of an NNRTI-based regimen as first-line antiretroviral treatment in resource-limited settings [4]. Specifically, experiences with a generic fixed-dose combination (FDC) with nevirapine have been widely documented in resource- limited settings [5–11]. In June 2001, the first pilot antiretroviral treatment programme was initiated in the Infectious Disease Depart- ment in Khmer-Soviet Friendship Hospital, Phnom Penh, Cambodia, with the support of Me ´decins Sans Frontie `res, a nongovernmental organization, in partnership with the National Center for the Control of HIV, AIDS and STD (NCHADS) and the Ministry of Health. At the beginning of the programme, an efavirenz-containing regimen was chosen as first-line therapy. Subsequently, in 2003, the first national recommendations were published, which proposed using stavudine, lamivudine and nevirapine in an FDC as first-line therapy. To conform to these national Correspondence: Dr Didier Laureillard, Ho ˆpital Europe ´en Georges Pompidou, 20 Rue Leblanc, 75015 Paris, France. Tel: 33 1 56 09 25 62; fax: 33 1 56 09 30 26; e-mail: didier.laureillard@egp.aphp.fr DOI:10.1111/j.1468-1293.2008.00597.x HIV Medicine (2008), 9, 514–518 r 2008 British HIV Association 514