0403 - Clinical Pharmacology kinetics doses interactions and adverse effects - EG

Question 1

Compare clinical pharmacology to therapeutics

Answer 1

Clinical pharmacology is about the principles behind the prescribing process, effects in human organism most particularly, therapeutics is the process of medical treatment

Question 2

List some of the unique aspects of a patient’s profile that need to be taken into consideration when considering a drug and dosing regime.

Answer 2

age, weight, sex, race, allergies, smoking history, alcohol history, diseases, pregnant/lactating, current therapy, intelligence.

Question 3

List some of the aspects of a drug profile.

Answer 3

name, class, action, pharmacokinetics, indications, contraindications/precautions, interactions, side effects, dosing regimen, monitoring, overdose.

Question 4

Define pharmacodynamics

Answer 4

study and description of mechanism of action of a drug

Question 5

Define pharmacokinetics

Answer 5

study and description of handling of a drug in and by the body

Question 6

Define pharmacogenetics

Answer 6

study of inheritance and influence of genetics on drugs and drug action

Question 7

Define drug clearance.

Answer 7

Drug clearance is the volume of plasma (or blood in some cases) cleared (i.e. from which the drug has been completely remove) per unit time.

Usually expressed as L/h.

Question 8

What does drug clearance determine?

Answer 8

The maintenance dose of the drug.

The maintenance dose rate is the dose per time required to maintain the plasma (or blood) concentration. The “steady state”.

Question 9

Define the volume of distribution.

Answer 9

The total volume in the body into which the drug appears to be distributed with a concentration equal to that of plasma.

Expressed as mg/L.

Question 10

What does the volume of distribution determine?

Answer 10

The loading dose of a drug.

Question 11

Define the half life of elimination of a drug.

Answer 11

The half life of elimination is the time for the concentration of the drug in plasma or blood (or amount of drug in body) to halve.

Expressed in units of time (usually hours).

Question 12

What does the half life of elimination determine?

Answer 12

The dosing interval.

Question 13

Define bioavailability.

Answer 13

The fraction of a drug which reaches the systemic circulation from defined route of administration.

Parental = 100%
oral is variable

Question 14

What are P-glycoproteins?

Answer 14

drug transporters, membrane efflux pumps. Specific proteins identified in cells whose activity is linked to explaining the variable bio-availability of some drugs as well as access to selected compartments.

Question 15

What are some of the functions of P-glycoproteins?

Answer 15

• limiting absorption from the gut
• blood-brain barrier
• ovarian, testicular, adrenal cortex protection
• hepatic and renal excretion
• protecting fetus

Question 16

What pathologies of the liver are particularly important in pharmacokinetics?

Answer 16

Primary Liver problems:
- decreased enzyme capacity
- decreased blood flow to liver lobules
- decreased liver blood flow per se.
- decreased drug transporters
Secondary Liver problems:
- bilirubin
- circulating proteins

Question 17

What pathologies of the kidney are particularly important in pharmacokinetics?

Answer 17

• renal dysfunction.

Drugs are handled actively and passively in the kidney. Dysfunction decreases excretion rate - leads to retention of some metabolites which can cause side effects.