For patients across Africa, the drugs on national formularies may be systematically mis-dosed — not because of supply failures, but because the genetic blueprints that determine how those drugs are metabolized have never been factored into prescribing guidelines. This blind spot has measurable consequences for the 1.4 billion people on a continent that harbors more genetic diversity than the rest of the world combined.
A systematic review published in Clinical Pharmacology and Therapeutics examined pharmacogenomic gaps across the WHO Model Essential Medicines List (EML) and the national EMLs of all 52 African countries. Of the 447 unique systemic medicines on the 2023 WHO EML, 58 — roughly 13% — carry established pharmacogenomic biomarker guidance, meaning known gene-drug interactions exist that should, in principle, inform dosing or drug selection. Across African national lists, which collectively catalogued 774 such medicines, approximately one in eight drugs per country was linked to actionable pharmacogenomic recommendations. The analysis also evaluated eight African countries for their capacity to implement pharmacogenomics-guided dosing, assessing whether appropriate drug formulations enabling dose adjustment were even registered and available.
This work matters beyond Africa. Pharmacogenomics has historically been shaped by data from European ancestry populations, creating compounding inequities: the populations with the greatest genetic diversity receive the least tailored drug guidance. Variants in CYP2D6, CYP2C19, and DPYD — enzymes central to metabolizing psychiatric medications, antiplatelet agents, and chemotherapy — show substantially different frequency distributions in African populations compared to European cohorts. An essential medicines framework that ignores these realities is not evidence-based in any meaningful sense. The study's scope is impressive, but its core limitation is structural: identifying the gap is not the same as closing it. Implementing pharmacogenomic testing at scale in low-resource settings requires infrastructure, trained personnel, and cost reduction in genotyping technologies. Nevertheless, this analysis serves as a high-resolution map of where targeted investment would yield the greatest therapeutic benefit — an incremental but necessary step toward precision medicine that actually reaches the populations who need it most.