title: The relationship of absorption characteristics and gastrointestinal side effects of oral antimicrobial agents.
abstract: Normal bowel flora play an important role in preserving gastrointestinal (GI) function. They inhibit colonization by pathogenic bacteria, help in the metabolism of by-products of drugs and endogenous substances, aid in the synthesis of vitamins, and stimulate nonspecific host immune systems that protect against potential pathogens. Antimicrobial agents that are poorly absorbed from the GI tract can substantially alter the bowel flora. Narrow-spectrum antimicrobial agents are less likely to disrupt the bowel flora than broad-spectrum agents. Drugs that undergo extensive enterohepatic circulation can also disrupt normal flora. Knowledge of the extent of GI absorption, bile excretion, and spectrum of activity allows prediction of the likelihood of GI side effects. For example, clindamycin, which is relatively poorly absorbed and has significant bile secretion, is associated with a high incidence of diarrhea. The use of an antibiotic with a relatively narrow spectrum, excellent GI absorption, and minimal bile excretion should reduce the incidence of GI side effects.
authors.affiliation: Mt. Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: R F
authors.initials: RF
authors.lastname: Grossman
mesh_terms: D000284:Administration, Oral; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D004755:Enterobacteriaceae / Q000254:growth & development; D006801:Humans; D007408:Intestinal Absorption; D007422:Intestines / Q000187:drug effects* / Q000382:microbiology; D013270:Stomach / Q000187:drug effects* / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents