Safety and tolerance of efavirenz in different antiretroviral regimens: results from a national multicenter prospective study in 1,033 HIV-infected patients.

Purpose: To evaluate the incidence and severity of adverse events (AEs) and treatment interruption (TI) with efavirenz in a population with a high rate of intravenous drug use (IVDU).

Method: This was a national, multicenter, and observational study of HIV-infected adult patients who were starting an efavirenz-containing regimen. Evaluations of AEs were made in routine clinical practice at baseline and at least 3 months later. A total of 1,033 patients were included from 60 participating hospitals; 20% were antiretroviral naive. The risk factor for HIV infection was IVDU in 62.3%, and 6.6% of participants were on methadone.

Results: AEs affected 29.3% of participants, and treatment was interrupted in 8.23%. The most frequent AEs were CNS disturbances that affected 24.1% participants; these AEs were considered related to efavirenz in 18.5% patients. AEs were not severe, and treatment had to be interrupted in 6% of patients. Other AEs were cutaneous rash (incidence of 5.9%; 2.4% of TI), gastrointestinal disturbances (1.45%; no TI), and elevation of liver function test (0.68%; no TI). Patients taking methadone had more AEs (39.7%), mainly CNS disturbances, and TI (19.1%). Cutaneous rash was more frequent among women. Psychoactive drug consumption, previous history of psychiatric disorders, antiretroviral experience, or previous nevirapine intolerance were not associated with higher incidence of AEs.

Conclusion: Safety and tolerance of efavirenz is good in most patients, even in a population with a high rate of IVDU. The most common AEs are CNS disturbances; they are not severe and rarely lead to TI.