A pharmacovigilance study of adults on highly active antiretroviral therapy, South Africa: 2007 - 2011

Of the 1.6 million South African people infected with human immunodeficiency virus (HIV), approximately 970,000 (55%) have been initiated on HAART. Despite these numbers, very little has been published about the safety profile of antiretroviral (ARV) medicines in the country. This study was performed at the Medunsa National Pharmacovigilance Centre and aimed to describe the demographic characteristics of patients enrolled in the pharmacovigilance surveillance study; highly active antiretroviral therapy (HAART) initiation regimen patterns; reasons for regimen changes; and adverse effects of ARV medicines.

A cohort study of HIV-infected individuals aged 15 years or older who were on ARV medicines was conducted at four sentinel sites.

After HAART initiation, with an average lapse of 17.8 months (range: 0 - 83.8 months), 2,815 patients were enrolled into the study. Results show that patients were observed for 1,606.2 person-years for pharmacy visits (collection of ARV medicines) and 817.1 person-years for clinical visits (consultation with the doctor). Females constituted 69.6% (1,958/2,815) of the study population. Almost all patients initiated HAART on first-line regimens (2,801/2,815). Some patients (6.7%, 190/2,815) dropped out of the study after HAART initiation. Reasons for regimen changes were not recorded for 2.5% (22/891) of the patients who changed regimens. The primary reason for regimen changes was drug-related toxicity (76.1%, 678/891), mostly evident in patients taking first-line regimens. Adverse effects experienced by patients were polyneuropathy (24.0%, 163/678); lipodystrophy (23.9%, 162/678); neuropathy (10.6%, 72/678); and suspected lactic acidosis (3.8%, 26/678).

The majority of prescribers complied with the HAART guidelines and initiated most patients on first-line regimens. However, adverse effects are evident in patients taking first-line regimens. We recommend that the Department of Health should introduce less toxic first-line ARV regimens. Future efforts will aim to initiate patients on HAART and enrol them into the study simultaneously to determine early risk profiles of ARV medicines.