[Prevalence, associated factors, and misuse of medication in the elderly: a review].

Most elderly people use at least one medication, and about one-third use more than five drugs simultaneously. Many patients have no access to the drugs they most need, and others use unnecessary or dangerous drugs. The mean number of drugs used by the elderly, as quoted in different studies, varies from 2 to 5. Significant predictors for such misuse of medication are older age, female gender, precarious health conditions, and depression. Cardiovascular drugs, anti-rheumatics, and analgesics are the most frequently consumed therapeutic classes. Multiple use, prescription of contraindicated drugs, redundant use, and inadequate training of the health care team are associated with adverse drug effects and interactions. Better quality of prescriptions and research on drug use can bring benefits to people aged 60 years or older.