Pharmacodynamics in Geriatric Patients: Effects of Age

Age-related pharmacodynamic changes are less understood due to challenges in measuring drug responses.

Cross-sectional studies providing data on age-related pharmacodynamic differences assume that the average differences between age groups reflect the changes individuals undergo as they age.

Notably, these assumptions may not accurately reflect changes over time due to difficulties in distinguishing between certain parameters.

However, changes in pharmacodynamics due to aging can alter drug responses.

For instance, benzodiazepines show increased sensitivity in older adults. Some cause stronger cognitive and sedative effects, even with unchanged drug levels in the body.

Also, warfarin shows greater inhibition of the synthesis of vitamin K-dependent clotting factors in older patients compared to younger ones at similar plasma concentrations.

Additionally, ꞵ-adrenergic receptor sensitivity declines with age, affecting drug responses.

Factors include impaired signal transduction, downregulation of ꞵ-adrenergic receptors, and decreased activity of Gs proteins. These factors necessitate drug dosage adjustments, with appropriate safety evaluation.