Prescribing optimally in the elderly: Understanding the pharmacology

The chronological age of 65 years is now recognized as a definition of an elderly person. All aspects of pharmacokinetics are affected by aging. The change in absorption is though, often not a major clinical problem in elderly, but significant changes can be observed in distribution, metabolism, and excretion of drugs. Due to reduced renal excretion and hepatic metabolism, the clearance of most of the drug is reduces in older adults. Adverse drug reactions (ADRs) occur about twice as often in the elderly, due to their more sensitivity to drugs than the younger. Inappropriate diagnosis, irrational prescribing, infrequent monitoring, polypharmacy and long-term therapy make them prone to various ADRs. Drug interactions are more frequent in the elderly because of polypharmacy. In spite of appropriate diagnosis, elderly patients are often inadequately managed. This may be due to ignorance of altered physiology of an elderly person, inappropriately too high dose prescribed, inadequate treatment of symptoms specially pain, pharmacodynamic changes of drug effecting in elderly and inappropriate monitoring. Studies have shown that an elderly patient is usually taking 3–12 drugs daily. A prescription always has inherent vulnerability of risk, if anticipated benefits are not properly balanced with foreseeable harm. This is especially important when the prescription is for elderly population as the functional capacity of all organs are reduced gradually after the age of 40 years, leading to higher incidence of diseases and ADRs. Therefore, the prescriber should be cautious about the age dependent changes, during calculating the dose.