Appropriate prescribing in the elderly: Current perspectives

Table 1 Pharmacokinetics and ageing

Absorption	↓ amount of saliva
	↑ gastric pH
	↓ gastric acid secretion
	↑ gastric emptying time
	↓ gastric surface area
	↓ gastrointestinal motility
	↓ active transport mechanisms
Distribution	↓ cardiac output
	↑ peripheral vascular resistance
	↓ renal blood flow
	↓ hepatic blood flow
	↓ body water
	↑ body fat tissue
	↓ serum albumin levels
	↑ for lipid soluble and decrease for water soluble drugs
Metabolic	↓ microsomal hepatic oxidation
	↓ clearance
	↑ steady state levels
	↑ half lives
	↑ levels of active metabolites
	↓ first pass metabolism due to reduced ↓ blood flow
Excretion	↓ in renal perfusion
	↓ in renal size
	↓ in glomerular filtration rate
	↓ tubular secretion
	↓ in tubular reabsorption

↑: Increased; ↓: Reduced.