System Observed alteration
General ↓ body weight
↓ basal metabolic rate
↓ body water
↓ percentage of lean body mass
↑ percentage of fat body mass
Circulatory ↓ cardíac output
↓ tissue blood flow
↓plasma albumin
Gastrointestinal ↓ gastric acid production
↓ gastric emptying rate
↓intestinal motility
↓blood flow
↓ absorptive surface
Hepatic ↓mass
↓blood flow (arterial and/ou portal)
Renal ↓ glomerular filtration rate
↓ tubular function
Pulmonary ↓vital capacity
(↑) Increase; (↓) Decrease
Table 1: Physiological alterations in the elderly with potential to influence drug pharmacokinetics (modified from Klotz [6]).