Interaction between different drugs is a common, and preventable, cause for toxicity reactions among elderly patients.

Up to five per cent of all hospital admissions occur because of adverse drug reactions. Often these occur because of interactions between different drugs. Older patients are especially vulnerable in this respect, as they are often taking many different medications.

Doctors in Toronto monitored admissions to hospital for toxic effects among a large group of patients prescribed various medications. They were able to identify many potential drug-drug interactions in these cases. For example, patients with digoxin toxicity were 20 times more likely to have taken the antibiotic clarithromycin in the previous weeks.

Computerised technology should be improved to make doctors more easily aware of such potential interactions, say the researchers. Then an alternative drug can be prescribed or, at the very least, the patient can be carefully monitored.

Source

Journal of the American Medical Association 2nd April 2003