Drug therapy in the elderly. Changes in drug pharmacokinetics and pharmacodynamics in patients with diabetes mellitus and thyroid gland dysfunction.

Question 1

who are the elderly

Answer 1

those defined by WHO as >65y.

are more likley to receive medication

Question 2

mistakes when rx eldery

Answer 2

Prescription of higher dose ( lower doses more effective)

Prescription of more dangerous drugs

Use of drug combinations that lead to interactions and produce adverse effects

Question 3

syndromes in elderly requiring unique drugs 
old 
ppl 
cant 
over
use 
drugs

Answer 3

Orthostatic hypotension
Poor nutrition
Constipation
Osteoporosis
Urinary incontinence
Dementia
Stroke

Question 4

why are age related phk difficult to produce

Answer 4

clinical trials usually use young healthy individuals in drug development

Question 5

changes phK in elderly

Answer 5

slower rate of abs of oral drugs

decreased hep func- reduced first pass
-increased bioavailability

less plasma albumin- more free drug - increased effect

decreased CO and renal func reduces drug clearance

altered elimination half life d/2- changes in maintenance dose

Question 6

what causes altered phD in elderly

Answer 6

loss of receptors

change in the secondary messengers

Question 7

effects of altered phD on specific drug action

Answer 7

warfarin -increased coag

heparin
- increased bleeding

opiods
-more analgesic effect

long acting benzo
- longer lasting sedation

Question 8

why are ADR’s more common in elderly

Answer 8

↑number of diseases
↑severity of disease
↑number of medications (also increases the chances of unintended drug reactions)

Question 9

examples of increased adr from drug interxn

Answer 9

diuretics with digoxin
-increased risk of hypokalaemia
digoxin intoxication

Question 10

drugs generally CI in elderly

Answer 10

Long-lasting benzodiazepines (confusion, sedation, falls)

Amitriptyline (excessive anticholinergic effect)

Question 11

effects of DB on phd

Answer 11

increased SC insulin absorption

reduced IM drug abs

reduced drug binding
-d/2 glycosylation of pp

decreased CYP450A3 activity
- lower drug met of benzo’s
anti arythmics

reduced hepatic clearance
-fatty liver

initial elevated renal clearance followed by decline

Question 12

Hyperthyroidism effect

Answer 12

increased drug metabolism

thyroid hormones activate cytp450

larger doses needed

decreased riboflavin abs

increased drug clearance d/2 increased renal BF

Question 13

Hypothyroidism

Answer 13

decreased met, increases toxicity risk

decreased gutmotility increases riboflavin abs

decreased renal bf,

Question 14

which drug induces thyrpid dysfunc

Answer 14

Amiodarone
because of its high iodine content
(which inhibits 5-deiodinase activity).