Background:Long-term toxicity of antiretroviral agents is rarely addressed in initial clinical trials. Effective pharmacovigilance is essential for long-term safety of antiretroviral therapy (ART).Materials and Methods:All adverse drug reactions (ADRs) reported due to ART between January 2014 and September 2016 were analyzed as per different drug regimens used. ADRs were also analyzed for system organ classification, seriousness, time relationship of ADRs with drug therapy, causality (as per the World Health Organization-Uppsala Monitoring Centre scale and Naranjo algorithm), and severity (Hartwig and Siegel scale). Comparison was done between (tenofovir + lamivudine + efavirenz [TLE]) and (zidovudine + lamivudine + nevirapine [ZLN]) regimens.Results:During a study period, 2983 patients were on ART. The most common drug regimen prescribed was TLE (1805) followed by ZLN (326). A total of 325 (10.89%) ADRs were reported in which 150 ADRs were reported in TLE regimens (46%) and 130 in ZLN regimens (40%). The mean age of patients with ADRs was 40 ± 12.56 years and men (58.1%) were more affected than women (41.8%). The most common system organ involved in ZLN regimen was blood (50, 39%) and skin (35, 27%), while it was neurological (63, 42%) and renal disorder (27, 18%) in TLE regimen. Most of ADRs were observed after 1 month of therapy (79.5%) and showed possible causal relation with drug therapy (78.15%). Majority of ADRs were mild in nature (86.7%). The serious ADRs were reported more in ZLN (18%) regimen as compared to TLE (9%) (P < 0.05).Conclusion:Both ART regimens are associated with ADRs affecting all body system; however, the frequency and severity of ADR are high with ZLN regimen.