Empirical Investigation of Factors Affecting Drug Bioavailability in Malnourished Paediatric Patients in Zamfara State

Malnutrition significantly alters drug disposition in children, yet the empirical evidence base on how severe acute malnutrition affects the bioavailability of commonly used paediatric drugs in Nigerian settings is limited. This study empirically investigated factors affecting drug bioavailability in malnourished paediatric patients receiving treatment at a therapeutic feeding centre in Gusau, Zamfara State, North West Nigeria. A prospective pharmacokinetic study design was employed. Forty malnourished children aged 6 months to 59 months with SAM and 40 adequately nourished children were enrolled as cases and controls. Amoxicillin and artemether-lumefantrine were selected as study drugs due to their programmatic importance in SAM management. Standardised oral doses were administered, and blood samples collected at defined time points for HPLC-based concentration analysis. Pharmacokinetic parameters derived included Cmax, Tmax, and AUC. Results showed significantly reduced amoxicillin AUC in SAM children compared to controls (mean 42.3 versus 74.8 mg.h/L; p < 0.001), and significantly delayed lumefantrine absorption (mean Tmax 5.2 versus 3.1 hours; p < 0.01). Malnutrition severity, albumin level, and co-existing oedema were significant predictors of reduced bioavailability. The study provides novel empirical pharmacokinetic data from a Nigerian SAM population, demonstrating clinically relevant bioavailability reductions that may necessitate dose adjustments and recommends pharmacokinetically guided dosing protocols for critically ill malnourished children. Keywords: drug bioavailability, malnutrition, paediatric pharmacokinetics, Zamfara State, severe acute malnutrition