Pharmokinetics

Question 1

What is increased in regards to non-polar molecules?

Answer 1

1. Rate of absorption from gut
2. Penetration into brain and other tissues
3. Rate of renal elimination

Question 2

4 factors affecting absorption of a drug

Answer 2

1. pH/ionization
2. Site/method of administration
3. Molecular weight
4. Lipid solubility

Question 3

4 factors affecting distribution of a drug

Answer 3

1. Permeability/lipid solubility
2. The blood brain barrier (tight junctions)
3. Drugs binding to proteins
4. Drugs divided into specific tissues

Question 4

How to treat aspirin poisoning?

Answer 4

Administer sodium bicarbonate, the pH of the urine will increase- aspirin (acidic drug) trapped in basic medium- cannot be reabsorbed into the plasma

Question 5

What are the 2 reactions involved in metabolism?

Answer 5

1. Catabolic reaction (can produce a more reactive compound)

2. Synthetic reaction (produces an inactive product)

Question 6

What are 3 intracellular enzymes found in the liver?

Answer 6

1. P450
2. Alcohol dehydrogenase
3. MAO

Question 7

What are the pathways for the of excretions of drugs

Answer 7

1. Urine
2. Faeces
3. Exhaled air
4. Sweat/milk

Question 8

What is a prodrug and what are its benefits

Answer 8

Prodrug= becomes active once it has been metabolised.

1. Beneficial if the drug is poorly absorbed in the GI tract
2. Fewer side FX
3. Opportunity for increased selectivity of the drug