ABSTRACT
Current antiretroviral treatment (ART) guidelines recommend different combinations that have led to major improvements in the management of HIV and AIDS in the developed and developing world. With the rapid approval of many agents; health care providers may not be able to familiarise themselves with them all. This lack of knowledge leads to increased risk of dose- prescribing errors; especially by non-HIV and AIDS specialists. The purpose of this retrospective non-experimental; quantitative drug utilisation study was to evaluate if antiretrovirals (ARVs) are prescribed according to the recommended prescribed daily doses (PDDs) in a section of the private health care sector in South Africa (SA). Analysed ARV prescriptions (49995; 81096 and 88988) for HIV and AIDS patients were claimed from a national medicine claims database for the period 1 January 2005 through to 31 December 2007. ARV prescriptions prescribed by general practitioners (GPs) with PDDs not according to the recommended ARV dosing increased dramatically; from 12.33 in 2005 to 24.26 in 2007. Those prescribed by specialists (SPs) increased from 15.46 in 2005 to 35.20 in 2006 and decreased to 33.16 in 2007. The highest percentage of ARV prescriptions with PDDs not according to recommended ARV dosing guidelines was identified in ARV regimens with lopinavir-ritonavir at a PDD of 1066.4/264 mg and efavirenz at a PDD of 600 mg prescribed to patients in the age group of Group 3 (19 years age ? 45 years). These regimens were mostly prescribed by GPs rather than SPs. There is a need for more education for all health care professionals and/or providers in the private health care sector in SA on recommended ARV doses; to avoid treatment failures; development of resistance; drug-related adverse effects and drug interactions
Subject(s)
Anti-HIV Agents , PrescriptionsABSTRACT
Background: The introduction of human immunodeficiency virus (HIV) protease inhibitors (PIs) has led to a dramatic decline in the morbidity and mortality associated with HIV infection. However; the concomitant use of PIs and other antiretrovirals (ARVs) can be complicated by drug-drug interactions (DDIs); adversely affecting levels of PIs. Methods: A quantitative; retrospective drug utilisation study was performed using data obtained from the medicine claims database of a pharmacy benefit management company during 2004; 2005 and 2006. The possible DDIs found among ARVS themselves were identified using the classification by Tatro.Results: The percentage of ARV prescriptions claimed of the total number of medicine items increased from 1.68(n = 43 482) during 2004 to 3.18(n = 51 613) during 2005; then to 4.74(n = 47 085) during 2006. A total of 1 326; 1 863 and 960 possible DDIs were identified among ARVs themselves for 2004; 2005 and 2006 respectively. Of these; ritonavir (unboosted or boosted) presented with the most possible DDIs; accounting for 74.28(n = 985) for 2004; 67.90(n = 1 265) for 2005; and 27.50(n = 264) for 2006. The highest prevalence of DDIs identified was between ritonavir (unboosted) and saquinavir (n = 974; 5) for 2005 and 2006; followed by indinavir (n = 490; 129; 155) for 2004 to 2006; and efavirenz (n = 274) for only 2004; then ritonavir (boosted); co-formulated as lopinavir/ritonavir; and efavirenz (n = 118; 88; 34) for 2004 to 2006; nevirapine (n = 49; 37) for 2004 and 2005; indinavir (n = 9) for 2004; and saquinavir (n = 22) for 2006.Conclusion: These findings indicate that concomitant use of PIs such as ritonavir; a potent cytochrome P450(CYP)3A4 enzyme inhibitor; and other ARVs is complicated by possible DDIs and therefore further studies need to be done on the ARV combinations and management of these DDIs. How to cite this article: Katende-Kyenda; N.L.; Lubbe; M.S.; Serfontein; J.H.P.; Truter; I. 2009. Analysis of possible drug-drug interactions between ritonavir and other antiretrovirals in a section of the private health care sector in South Africa. African Journal of Primary Health Care et Family Medicine; 1(1); Art. #21; 6 pages. DOI: 10.4102/ phcfm.v1i1.21