CLINICALLY SIGNIFICANT DRUG-DRUG INTERACTION IN A LARGE ANTIRETROVIRAL TREATMENT CENTRE IN LAGOS, NIGERIA

Abstract

Background An important cause of treatment failure to antiretroviral therapy (ART) is the potential interaction between the antiretroviral (ARV) drugs and concomitant drugs (CD) used for the treatment of opportunistic infections and comorbid ailments in HIV-infected patients. Objectives The study evaluated potential Clinically Significant Drug Interactions (CSDIs) occurring between recommended ART regimens and their CD. Method This study was carried out in a large HIV treatment centre supported by AIDS Preventive initiative in Nigeria (APIN) clinic in a teaching hospital in Lagos, Nigeria, caring for over 20,000 registered patients. Electronic Medical Records (EMRs) of 500 patients, who received treatment between 2005 and 2015, were selected using systematic random sampling, reviewed retrospectively, and evaluated for potential CSDIs using Liverpool HIV Pharmacology Database and other databases for drug-drug interaction check. Results Majority of patients, 421 (84%) prescribed CDs were at risk of CSDIs, of which 410 (82%) were moderate and frequently involved co-trimoxazole + combinations of Nucleoside Reverse Transcriptase Inhibitors (NRTIs) such as zidovudine (or stavudine) /lamivudine 386 (77.2%) and Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs) or Protease Inhibitors (PIs) + artemisinin-based combination therapies (ACTs) 296 (59.2%). Age (p=0.13), sex (p=0.32) and baseline CD4+ cell counts (p=0.20) were not significantly associated with CSDIs. The interactions, however, were significantly associated with the development of antiretroviral treatment failure (p <0.001) which occurred in nearly a third 139 (27.8%) of the patients. Conclusion There is a high prevalence of CSDIs between ART and CDs, most of which were categorized as moderate. Further studies are required to evaluate the pharmacokinetic and clinical relevance of these interactions.