Influence of food on absorption of antimicrobial drugs

Abstract

Interactions between food and drugs affecting drug absorption are widely recognized in human medicine but have received little attention in the veterinary sphere. The most common outcome of these interactions is reduced or delayed absorption of the drug, although in some instances absorption can be increased or unaffected. The mechanisms responsible are complex and involve both food- induced changes in gut physiology and direct interactions between food components and drugs. The clinical significance of interactions affecting antimicrobial drugs is uncertain. However, impaired absorption is more likely to hinder antimicrobial efficacy than to help it. Accordingly, it seems prudent to fast patients for 2 hours before and 2 hours after administration of those agents whose absorption can be impaired substantially by food, namely most penicillins and tetracyclines, some cephalosporins and certain erythromycin products. A few antimicrobial drugs may not require food restriction (chloramphenicol, erythromycin estolate, hetacillin) and some could be given with food to improve absorption (erythromycin esters, griseofu1vin, nitrofurantoin) or reduce gastric irritation associated with dosage (doxycyc1ine, metronidazole, nitrofurantoin).