Background Adverse effects caused by pharmacotherapy are a problem that particularly affects the older.

Purpose To help prevent iatrogenic problems, the authors wanted to measure and describe them in a particularly vulnerable population, recently hospitalised patients aged over 70.

Materials and methods A retrospective analysis was performed of 100 new patients aged 70 and older, hospitalised in internal medicine between 1 April 2011 and 30 June 2011. Only side effects commented upon in the patient record that justified stopping or changing the dose of the drug were selected.

Results Of the 100 patients, there were 70 women and 30 men. The average age was 85 years. 30 patients (30%) experienced an adverse effect. These were 25 women and 5 men, average age 83.5. Of these 30 patients, 25 patients (83%) required the drug involved before admission while for 11 patients (37%) the reason for hospitalisation was related to the iatrogenic effect. For five patients (17%) the drug was prescribed during hospitalisation. When the iatrogenic problem was related to the reason for hospitalisation, drugs involved were psychotropic drugs, diuretics, antihypertensives and antiplatelet agents, anticoagulants, NSAIDs and oral hypoglycaemic agents. When the iatrogenic problem was related to a drug prescribed during hospitalisation, drugs involved were neuroleptics, cortisone and diuretics.

Conclusions The adverse effects of drugs in the older are an important factor of morbidity and often underestimated. 11% of hospitalisations are related to iatrogenic effects. Efforts to prevent iatrogenic problems should reflect the risk/benefit ratio. The introduction of drugs known to cause problems requires close monitoring; adverse effects require early and rapid reporting and more frequent dialogue between hospital doctors and other health professionals prior to the discharge of the patient. The pharmacist's role in the validation of requirements remains central.