Evaluation of drug-drug interactions among patients with chronic kidney disease in a South-Eastern Nigeria tertiary hospital: a retrospective study

Introduction The risk of drug-drug interactions (DDIs) is high in patients with chronic kidney disease (CKD) necessitating dose adjustments or the avoidance of drug combinations. This study aimed to evaluate DDIs among patients with CKD in the University of Nigeria Teaching Hospital (UNTH), Enugu, South-East Nigeria. Methods This study was a retrospective review of patients with CKD who received treatment at the nephrology unit of UNTH between January 2004 and December 2014. The drug-drug interactions (DDIs) of the prescribed drugs were classified using the RxList interaction checker. The IBM SPSS Version 21.0 was utilized for statistical analysis with P-value ≤ 0.05, considered statistically significant. Results A total of 749 DDIs were identified from the folders of the 169 patients with CKD that were eligible. Majority were above 50 years old and in stage 4 or 5 CKD. Furosemide, lisinopril and amlodipine were the most frequently prescribed drugs and had the greatest likelihood for nephrotoxicity. The number of medications and hypertension (as co-morbidity) were significant and independent predictors of DDIs among the patients. About 70% of the drug combinations required monitoring as they fell within the "significant category" of the RxList interaction checker. The most common interactions were between lisinopril and furosemide; furosemide and calcium carbonate; lisinopril and calcium carbonate. Conclusion The prevalence of DDIs was high among the CKD patients. Prescribers and pharmacists in Nigerian hospitals may need to pay close attention to prescriptions of patients with CKD to identify, prevent and resolve undesirable DDIs.