2- Understanding when drug therapeutic regimes might need changing

Question 1

List 4 factors that affect drug absorption

Answer 1

If the drug is lipid soluble
Formulation of the drug
Degree of ionisation of the drug

The surface area of the absorptive surface
pH
GI motility

Question 2

List 4 factors that affect drug distribution

Answer 2

Bound to plasma proteins or not

High body fat or water content for lipid/water-soluble drugs

If the drug is lipid soluble (high) Or water-soluble (low)

If it is a weak base (high) or weak acid drug(low)

Question 3

List 4 factors that affect drug metabolism?

Answer 3

Plasma protein binding
Lipid soluble drug (high)
Protective chemical groups
Blood flow to liver
Quantity of drug metabolising enzymes

Question 4

List 4 factors that affect drug excretion clearance?

Answer 4

Water soluble drugs (high)
Ionisable drug (High)
Drug-drug interactions
Quantity of drug transporters
Blood flow & GFR to kidney
Plasma protein binding

Question 5

Name 2 altered pharmacokinetics factors of the drugs pathway in the neonate

Answer 5

Lower excretion clearance (drug tubular secretion takes longer)
Lower metabolic clearance (Reduced hepatic function)

Question 6

T/F doses of drugs tend to need increasing in the neonate

Answer 6

False = RARE - usually need reducing

Question 7

Name 2 altered pharmacokinetics factors of the drugs pathway in the geriatric

Answer 7

Reduced bioavailability (absorption reduced - ^ pH, less microvilli)
Lower excretion clearance

Question 8

How does chronic cardiovascular disease affects a drugs life? & how is this dealt with?

Answer 8

Decreased blood flow = lower clearance for highly cleared drugs (e.g. anaesthetics)

Avoid drugs with a high clearance

Question 9

T/F Liver disease has an affect on drug metabolism

Answer 9

T/F - little effect until 80% functional loss

Question 10

Should a drug ideally have a low or high therapeutic index?

Answer 10

High