Prevalence and severity of adverse drug reactions among adult patients using default first line and modified antiretroviral combinations in Mbeya region, Tanzania

Abstract

Background information: For more than three decades now in the world, HIV /AIDS has emerged as a serious medical problem. The Government of Tanzania responded by provision of free antiretroviral (ARV) medicines to patients. The goals of ART are to provide maximal and durable suppression of viral load in patients in expectation of halting the disease progression; preventing/delaying medicine resistance, among others. Mbeya region is among the ART beneficiaries and ARVs provision started in late 2004. The antiretroviral used in the program by then included: zidovudine, didanosine, lamivudine, Abacavir, nevirapine, efavirenz, lopinavir, ritonavir , saquinavir and stavudine. Stavudine has been withdrawn from new default first line due to high adverse drug reactions. Although ADRs from these medicines are known worldwide, as a matter of fact, adverse reactions vary among various populations and geographical locations. Therefore, data that are derived from within the country are more plausible for patients monitoring, treatment guidelines review, planning and decision-making than those borrowed from another country. In response to that, a study to document the commonly reported ADRs in Tanzania was done in Dar es Salaam and Mbeya regions. However, the study reported ADRs from stavudine-based combination which was a default first line at that time but due to its higher adverse effects, currently is no longer initiated. Therefore, a new default combination is practiced which include zidovudine, lamivudine and efavirenz. Similarly, this combination has its substitutes which include nevirapine, tenofovir and emtricitabine. The last two substitutes were not evaluated in the previous studies because they were yet to be introduced in the programme. This change in default combination of ARVs first line and introduction of two substitutes in combination based regimen, demands for a follow up study to determine their adverse effects. viii Objective: To assess prevalence and severity of adverse drug reactions among adult patients using new default first line and modified antiretroviral combinations in Mbeya region, Tanzania Methodology The data (prevalence and severity of ADRs) for this study was collected retrospectively from Care and Treatment Clinic form number two (CTC 2) found in each patient’s files receiving antiretroviral therapy in Mbeya referral, regional and three district hospitals in the region. In these forms, ADRs that were reported by patients were documented by clinicians attending them. ADRs were considered as minor if the patient induced with ADR continued with the same medicines or serious when patient was switched to other medications. A study sample of 639 patients files were studied of which comprised of; 280(AZT/3TC/EFV), 280(AZT/3TC/NVP) and 79(TDF/FTC/EFV). Statistical Package for Social Science, Chi-square and Fisher’s exact tests were used to analyze the data. Results It was found that the overall prevalence of ADRs from use of new default first line combination was: skin rashes (1.07%), peripheral neuropathy (2.14%) and liver toxicity (0.36%). On the other hand, the severity was; 1 case of serious liver toxicity, 6 cases of mild peripheral neuropathy, 3cases of dry skin rash and 1 case of mild anaemia. Conclusion and Recommendation: The finding suggests that the new default first line combination is safer to the old one and therefore, recommended to continue to serve as default first line until when a better option is found.