Drug-Food Interactions

Abstract

The magnitude of pharmacological response to an orally administered drug is directly related to the extent and rate of gastrointestinal absorption of the drug. The absorption of drugs is influenced by many factors such as gastric pH, gut motility, and structure of the absorptive surface (Levine, 1970). The mixing of drugs with foods or beverages may alter these factors affecting the absorption through changes in their ionisation, stability, solubility, or transit time. Thus, food intake may increase the bioavailability of many drugs while it reduces that of others (Welling, 1977; Melander, 1978). The reduced absorption may result in prolonged drug action, and conversely when absorption is increased the blood level may be increased, perhaps to toxic levels. The clinical significance of drug-food interactions is reviewed in this chapter.