Elderly

Question 1

What are the 3 main reasons for pharmacodynamic changes in the elderly?

Answer 1

1) number of drug receptors decreased/altered affinity for drug molecules
2) haemostasis changes and conditions such as postural hypotension become more prevalent
3) more susceptible to confusion

Question 2

What factors affect drug distribution in the elderly?

Answer 2

Reduced saliva production
Increased gastric pH
Delayed gastric emptying 
Decreased GI motility
Decreased GI and regional blood supply

Question 3

How does drug distribution change in the elderly?

Answer 3

Increased mass of adipose tissue - increased Vd of lipid soluble drugs
Decreased lean muscle mass
Decreased total body water - reduced Vd of water soluble drugs
Decreased albumin

Question 4

How does hepatic function change in the elderly?

Answer 4

Decreased albumin
Reduced hepatic blood flow - reduced first-pass metabolism
Reduced metabolic clearance - reduced P450 pathway

Question 5

How does renal function change in the elderly?

Answer 5

Reduced kidney size results in reduced GFR