Lecture 7 - elderly

Question 1

describe physiology and ageing of elderly people

Answer 1

considerable variability. individualist assessment and targets

loss of total body water and muscle mass - increase in body fat

presentation/ signs/ symptoms may change

Question 2

describe physiological changes affecting absorption

Answer 2

physiological changes - increase gastric pH or decrease GI mobility and blood

clinical effects are no clinical effect on the majority of drugs. calcium requires acidic environment for optimal absorption. enter-coated medication forms with increased gastric pH.concurrent use of antacids or PPIs might affect absorption

Question 3

what are physiological changes affecting volume of distribution.

Answer 3

reduced body water has ab effect of reduced volume of distribution for hydrophilic drugs fro example, lithium

reduced lean body mass has reduced volume of distribution for drugs that binds t muscles eg digoxin

increased body fat increases volume of distribution for lipophilic drugs eg diazepam and trazodone

reduced album increases amount in percentage of unbound or free drug eg warfarin and phenytoin

Question 4

what are physiological changes affecting metabolism

Answer 4

first pass metabolism is decreased by 1% per annum in people aged over 40 years

metabolic clearance of drugs by the liver may be reduced by a reduction in blood flow, and decreases CYP450 system and decrease liver size and mass

Question 5

what are metabolic pathways affecting phase I and phase II reactions

Answer 5

phase I reactions (oxidation, reduction, hydrolysis) conversion to metabolites of lesser or equal or greater effect for example, diazepam and theophylline

phase II reactions include conversion to inactive metabolites such as lorazepam and temazepam