Introduction to Clinical Pharmacology

Question 1

What is pharmacology?

Answer 1

Pharmacology is the study of drugs and their interactions with the body

Question 2

What is a drug?

Answer 2

A chemical substance, which, when administered to a living organism, produces a biological effect.

Many substances, such as insulin or thyroxine, are endogenous hormones but are also drugs when they are administered intentionally.

Drug can be a natural product e.g. epinephrine, insulin, steroid hormone
It can be semi synthetic e.g. modified versions of insulin
Totally synthetic e.g. salbutamol

Question 3

What is a medicine?

Answer 3

Amedicineis a chemical preparation, which usually contains >= 1 drug(s), administered with the intention of producing a therapeutic effect.

Medicines usually contain other substances (excipients, stabilisers, solvents, etc.) besides the active drug, to make them more convenient to use.

Question 4

What is clinical pharmacology?

Answer 4

Clinical pharmacology: encompasses all aspects of drug therapy in clinical practice, from basic mechanisms to practical prescribing, to the effects of drug usage in whole populations

Question 5

What is therapeutics?

Answer 5

Therapeutics:treatment and care of apatientfor the purpose of preventing, supressing or curing a disease or alleviating pain or injury.

Question 6

What is the average number of prescription pills a person in the UK will take in their lifetime?
200
800
5000
14,000
27,000

Answer 6

27000

Question 7

Pharmacodynamics

Answer 7

Definition: The effects of a drug on the body

How drugs act at the target (e.g. stimulate/inhibit it)
1 = Mechanism of action of a drug

1. Mechanism of action of drugs
   Targets for drug action
   How drugs act at the target
   How the drug produces an action within a cell
2. Influence of drug concentration on the magnitude of response
   Graphical representation of concentration-effect relationships
   Therapeutic versus toxic effects

Question 8

Study of pharmacodynamics allows us to:

Answer 8

1. Determine the appropriate dose range for patients

2. Compare the effectiveness and safety of one drug to another

Question 9

Pharmacokinetics

Answer 9

Definition: What the body does to a drug

Question 10

Study of pharmacokinetics allows us to:

Answer 10

Design and optimise treatment regimens for individuals e.g. deciding on the route of administration, frequency of drug administration, duration of treatment

Question 11

Explain the four phases of pharmacokinetics

Answer 11

Absorption
From site of administration into the blood

Distribution
Drug can reversibly leave the bloodstream and distribute into the interstitial and intracellular fluids of tissues
Metabolism
Body inactivates the drug through enzymatic modification
Excretion
Drug is eliminated from the body in urine, bile or faeces

Question 12

Relevance of pharmacokinetics to prescribing

Answer 12

Absorption
Affects the route of administration of a drug

Distribution
Affects the dose of a drug given and the interval between dosing

Metabolism
Affects the combinations of drugs you can give together
Affects the route of administration

Excretion
Dose adjustments, or a change on route of delivery may be needed in people with impaired excretion mechanisms (e.g. renal disease)