Incidence and risk factors for rash in Thai patients randomized to regimens with nevirapine, efavirenz or both drugs

Objective: To determine the incidence and risk factors for rash in Thai patients taking four different non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens. Methods: HIV-positive antiretroviral-naive patients enrolled in the 2NN study in Thailand and followed for at least 1 week were included. Patients were randomized to efavirenz (EFV) 600 mg once daily (OD) versus nevirapine (NVP) 200 mg twice daily (BD) versus NVP 400 mg (OD versus NVP 400 mg OD + EFV 800 mg OD with stavudine/lamivudine. Results: Of 202 patients 95 (47%) and 69 (34.2%) developed a rash from all reasons and from NNRTI respectively. For NNRTI-related rash the incidence were EFV (20%) NVP BD (21%) NVPOD (38%) and NVP + EFV (67%). The proportions of patients with grade I II and III within the four treatment arms are as follows: EFV 4.3 13 and 2.9%; NVP BD 2.3 5.9 and 2.3%; NVP OD 12.8 19.1 and 6.4%; and NVP + EFV 11.9 47.6 and 7.1%. Multivariate analyses showed females with CD4 cell count =250 x 10(6) cells/l high body mass index (>21.3 kg/m(2) and a rise in CD4 (=53 x 10(6) cells/l) and alanine aminotransferase (ALT) (=34 U/l) at week 4 to be risk factors for rash. Conclusions: Thai patients had a high incidence of NNRTI- related rash when treated with NVP + EFV or NVP OD. NVP if used BD had the same rash incidence as EFV for rash of all grades. Females and persons with earlier HIV disease or with a large rise in CD4+ cell count after starting therapy are at greater risk for NNRTI-related rash. (authors)