Objective: To determine the incidence and risk factors for rash in Thai patients takingour 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 o 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 tavudine/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 incidences were EFV (20%), NVP BD (21%), NVPOD (38%) and NVP + EFV (67%). The proportions of patients with grade, II and III within the four treatment arms are as follows: EFV, 4.3, 13 and 2.9%; NVP BD, 2.3, 15.9 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 × 106 cells/l, high body mass index (>21.3 kg/m2 ), and a rise in CD4 (≥53× 106 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 ash 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