Dexamfetamine Absorption and Gastric pH Dependence
Dexamfetamine is a weak base, so increases in gastric acidity have limited clinical relevance for oral absorption compared with clinically relevant reductions in gastric pH produced by dedicated acidifying agents. [1], Amfexa (dexamfetamine) SmPC
Formulation and Documented Drug–pH Interactions for Amfexa
Amfexa prescribing information lists “gastrointestinal acidifying agents” as lowering absorption of amfetamines. Amfexa (dexamfetamine) SmPC, Dexamfetamine sulfate SmPC
Examples of acidifying agents listed include ascorbic acid and fruit juices. Dexamfetamine sulfate SmPC, Dexamfetamine sulfate SmPC
The effect of food on dexamfetamine absorption has not been studied, so a specific gastric-pH effect from a doughnut cannot be quantified for dexamfetamine. Dexamfetamine sulfate SmPC
Clinical Significance of “Acidification” from Doughnuts
No evidence is available that a doughnut meaningfully acidifies gastric pH to a degree comparable to listed gastrointestinal acidifying agents such as ascorbic acid or fruit juices. Amfexa (dexamfetamine) SmPC
For weak bases, absorption changes are more dependent on clinically relevant elevations of gastric pH and drug solubility than on typical dietary components. [1]
Practical Medication-Use Guidance
Amfexa should be taken in a standardized manner relative to meals to reduce day-to-day variability in exposure. Dexamfetamine sulfate SmPC
The magnitude of absorption reduction expected from doughnuts cannot be established from available product labeling or pharmacokinetic evidence. Dexamfetamine sulfate SmPC