Adverse drug reactions in the elderly.

Medications probably are the single most important health care technology in preventing illness, disability, and death in the geriatric population. Age-related changes in drug disposition and pharmacodynamic responses have significant clinical implications; increased use of a number of medications raises the risk that medicine-related problems may occur. The relationship between increased use of drugs including the prescription medication and elderly is well established. Majority of ADRs (80%) causing admission or occurring in hospital are type A reactions. Although less common occurring in elderly, type B ADRs may sometimes cause serious toxicity. Studies have correlated the integral association between old age and increased rate of adverse drug reactions arising out of confounding association between age and polypharmacy contributed by age-related changes in pharmacodynamics and pharmacokinetics at least for some medical conditions. A drug combination may sometimes cause synergistic toxicity which is greater than the sum of the risks of toxicity of either agent used alone. But, strategies to increase opportunities for identifying ADRs and related problems have not been emphasised in current international policy responses especially in India to the increase in elderly population and chronic conditions. Careful epidemiological studies that encompass large numbers of elderly drug users are required to obtain this information as increased knowledge of the frequency and cost of adverse drug reactions is important in enabling both more rational therapeutic decisions by individual clinicians and more optimal social policy.