Changes in Pharmacokinetics and Pharmacodynamics in the Elderly Patient

Abstract

The use of pharmacologic agents in elderly patients is one of the most difficult aspects of patient care. An understanding of the common physiologic changes expected with aging is helpful to anticipate changes expected in pharmacokinetic parameters. Distribution, metabolism, and excretion are significantly altered for many drugs. In addition, pharmacodynamic variations in elderly patients may increase or decrease sensitivity to a medication independent of pharmacokinetic changes. These alterations are particularly noteworthy with cardiovascular and central nervous system agents. Current controversies regarding the application of estimation of renal function to drug dosing and use of the Beers criteria of medications potentially inappropriate in the elderly are discussed.

Factors related to excessive polypharmacy (≥15 medications) in an outpatient population from Colombia

“…The correct prescription in the elderly people is difficult because in many studies this population is often excluded, and the approved doses may not be adjusted for them . In addition, many medications should be used with caution because of age‐related changes in pharmacokinetics and pharmacodynamics …”

General practitioners' prescribing patterns for the elderly in a province of Iran

“…The proper use of pharmacological products is a challenging aspect in the care of older patients 1. Inappropriate prescribing of medicines for the elderly is commonly observed throughout the world with prevalence ranging from 5.8 to 41% in Europe 2.…”

Pharmacotherapy in the ageing patient: The impact of age per se (A review)

“…Chronological age-based clinical decision-making is a generalised approach which neglects the enormous heterogeneity that exists in the health status and responses to medications in older patients (Hutchison and O'Brien 2007;Cho et al, 2011). Moreover, chronological age is not a reliable selection criterion for the identification of patients who need treatment interventions, such that eligible patients may be falsely excluded (Schuurmans et al, 2004).…”

“…Physiological changes that affect the pharmacodynamic behaviour of a medication include altered receptor number, receptor affinity, and homeostatic reserve (Bowie and Slattum, 2007). The altered sensitivity of ␤1-adrenergic receptors is a classic example of pharmacodynamic alterations in the elderly, presenting as a decreased response to ␤1-adrenergic agonists and an increased response to ␤1-adrenergic blockers (Hutchison and O'Brien, 2007). The number of cardiac muscarinic receptors also decreases with advancing age (Poller et al, 1997).…”