Regional anesthesia for acute pain management in elderly patients

Table 1 Pharmacokinetics alterations with aging[5,7]

Organ system	Deficits with aging
Liver	Decrease in hepatic blood flow will result in reduction of first pass elimination, phase I metabolism affected earlier than phase II
Kidneys	Reduction in renal blood flow cause decrease in both creatinine clearance, glomerular filtration rate and tubular secretion activities
Plasma drug-binding proteins	Decrease in albumin or other binding proteins will result in higher fraction of plasma free drug
Fluid distribution	Decrease in total body water and muscle, and increase in total body fat may results in smaller effective dose and longer duration of drug effect, especially for lipophilic drugs