Drug-induced hyponatremia. Three cases in elderly patients.

Three cases of drug-induced hyponatremia were seen during a three-month per iod in the same 27-bed internal medicine unit. Two were due to carbamazepin e and the one to fluoxetine. All three patients were elderly. Age-related a lterations in the regulation of water and sodium stores and the frequent co morbidity of elderly patients are associated with an increased risk of hypo natremia, in particular due to drugs. Inappropriate andiuretic hormone secr etion may also play a role. Drug use is often overlooked as a possible caus e of hyponatremia. The main drugs known to cause hyponatremia are reviewed. They include diuretic agents, oral antidiabetic agents, neuroleptics, anti depressants, nonsteroidal antiinflammatory drugs, and some aniticancer agen ts.