ABSTRACT
Unfortunately, a number of important drugs react chemically with all antacids containing calcium, aluminium or magnesium, if any of these are present in the stomach or duodenum when the drug is swallowed. Many clinicians are unaware of the risk, and since antacids are so widely consumed by patients who ‘don’t think it worth mentioning’ to the doctor or nurse, the problem needs determined action to prevent it. Pharmacists, too, need to reinforce this message at every repeat dispensing, and to ask patients about prescription drugs whenever they sell an antacid over the counter (OTC). For those curious enough to wish to know the antacid–drug interaction involved, there are four. It includes formation of a chemical complex – complexation, adsorption of the drug by the antacid, resin binding and destruction of a drug’s acid-resistant coating due to the increased pH in the stomach that results from the antacid.
