Adverse reactions as a cause of hospital admission in the aged.

Truly elderly people comprise an increasingly large fraction of the population and consume a disproportionate amount of drugs. Over the last 25 years a number of different studies have illustrated that advancing age is associated with adverse drug reactions (ADRs). Advancing age is also associated with polypharmacy and multiple pathology, and this complex inter-relationship makes it difficult to conclude that age itself is a causative factor for ADRs. ADRs resulting in hospital admission have been the subject of study for many years, but it has not been consistently demonstrated that advancing age is a predisposing factor. Early studies used the method of intensive inpatient monitoring and identified digoxin, diuretics, aspirin, psychotropics and cytotoxics as drugs of concern. Smaller more recent studies have used more sophisticated statistical techniques to identify predisposing factors. Nonsteroidal anti-inflammatory drugs have been added to the list of drugs that may cause ADR-related hospital admission. Polypharmacy, and altered pharmacokinetics and pharmacodynamics are possible causative factors; however, variable compliance and multiple pathology may cause difficulties with attributing causality. Some basic guidelines for sensible prescribing would almost certainly result in fewer ADRs in the elderly, including those ADRs severe enough to result in hospital admission.