Pharmacokinetics in Geriatric Patients: Effect of Age on Drug Absorption

As people age, various changes in body systems, including the gastrointestinal tract, skin, eyes, and pulmonary system, can affect drug absorption and efficacy.

The gastrointestinal tract experiences increased gastric pH, delayed emptying, and decreased motility but does not typically alter oral drug absorption.

Transdermal drug delivery is optimal for older individuals, offering unaffected drug absorption and reduced side effects.

In contrast, subcutaneous absorption is influenced by changes in vascular capillaries and lymphatic channels, with drug molecule size being a key determinant of passage.

Older adults have altered lung anatomy and physiology, including enlarged alveoli, varied elasticity, and increased residual volume, all of which can influence the absorption of inhaled drugs.

For instance, they require lower doses of inhaled anesthetic drugs than young adults.

Lastly, for ocular drugs, age-related alteration in the choroid and Bruch’s membrane thickness may affect drug permeability from the sub-conjunctival space into the vitreous humor.