Background: Inter-individual variability in response to antiplatelet therapy poses a significant challenge in the secondary prevention of ischemic heart disease (IHD). The bioactivation of clopidogrel relies heavily on the cytochrome P450 enzyme system, particularly the CYP2C19 isoenzyme. While loss-of-function alleles (CYP2C19*2 and *3) are known to reduce therapeutic efficacy globally, localized data on genetic polymorphisms and corresponding clinical outcomes within East African populations remain sparse. Methods: This study utilized a robust bioanalytical approach to correlate CYP2C19 genotypes with clinical outcomes in IHD patients. Genomic DNA was extracted from whole blood samples of patients undergoing routine clopidogrel therapy. Genotyping was performed using real-time polymerase chain reaction (RT-PCR). Standardized High-Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) was validated and deployed to quantify active clopidogrel thiol metabolite concentrations (Cmax and Tmax). Platelet reactivity was monitored alongside clinical endpoints, including major adverse cardiovascular events (MACE), over a 6-month follow-up period. Results: Genetic screening revealed a high prevalence of intermediate (34.2%) and poor (8.5%) metabolizer phenotypes. Pharmacokinetic profiling validated that carriers of the loss-of-function CYP2C19*2 allele exhibited a statistically significant decrease in active metabolite Cmax compared to extensive metabolizers. Consequently, poor metabolizers demonstrated heightened residual platelet reactivity, which directly correlated with a 2.4-fold increased risk of recurrent ischemic events (p < 0.05). Conclusion: These findings underscore the critical utility of integrating bioanalytical and pharmacogenomic screening tools in cardiovascular care. Tailoring antiplatelet selection based on localized genetic profiles holds immense potential to reduce treatment failure, optimize therapeutic outcomes, and advance precision medicine in regional cardiovascular care paradigms.

Dr. Jordan Garvin Bakwatanisa has completed his Bachelor of Pharmacy degree from Mbarara University of Science and Technology (MUST), Uganda, and is currently an active academic researcher serving as a Masters of Pharmacology Fellow at the same institution. He has extensive professional experience in pharmaceutical management and clinical care. His research interests lie at the intersection of clinical pharmacology, cardiovascular therapeutics, and personalized medicine. Driven by a commitment to public health advocacy, he leads initiatives aimed at enhancing therapeutic efficacy and patient safety within regional healthcare systems.