Extreme Bioavailability Variability

Extreme bioavailability variability from 5-200% characterises drugs exhibiting substantial interindividual absorption differences. Formulation-related variability from pharmaceutical differences causes content uniformity failures. Physiological variability from gastrointestinal motility and pH differences explains absorption fluctuations. Drug interactions from concomitant medications dramatically alter absorption. Individual metabolism variation produces wide exposure differences.

Narrow therapeutic index drugs exhibiting extreme variability necessitate therapeutic drug monitoring. Bioequivalence studies establish interchangeability despite high variability. Modified-release formulations reduce variability through controlled absorption. Formulation optimisation minimises absorption inconsistency. Regulatory submissions justify dosing recommendations accounting for variability.