Intro to Pharmacology

Question 1

How are drugs available?

Answer 1

• General sale medicines
• Pharmacy medicines
• Prescription only medicines
• Controlled medicines

Question 2

What are general sale medicines?

Answer 2

Medication approved to be sold in any shop.

Does not need to be supervised by a healthcare professional (are approved for low doses eg. paracetamol)

Question 3

What are pharmacy medicines?

Answer 3

Can only be sold in shop under supervision of registered pharmacist, may ask safety questions and may prompt to see GP if drugs not working.

Question 4

What are prescription only medicines?

Answer 4

May only be supplied to those with valid prescriptions, mostly by doctors but some other pros can also prescribe.

Question 5

What are controlled medicines?

Answer 5

Prescription only, also covered by misuse of drugs regulations.
Subject to additional requirements
Usually illegal to posess without prescription

Question 6

In what ways can we prescribe?

Answer 6

• Community prescription (asks for drugs to be dispensed)

- Hospital drug kardex (asks for drug to be administered)

Question 7

Why are drugs prescribed?

Answer 7

• Treatment of chronic conditions; long term prescribing
  ie. diabetes, asthma, cancer
• Prevention of medical problems; long term prescribing
  ie. primary prevention of heart disease, vaccination
• Short term management of acute problems
  ie. antibiotics for infections
• Prescription of non-pharmaceuticals
  ie. urinary catheters, gluten free foods`

Question 8

What are the 2 key aspects of pharmacology?

Answer 8

• Pharmacodynamics

- Pharmacokinetics

Question 9

What is pharmacodynamics?

Answer 9

What drug does to us
Involves study of how drug interacts with its target.
Common targets are: -receptors
-enzyme systems
- transporters
Drugs may activate or inhibit the pathways they target.

Question 10

What is pharmacokinetics?

Answer 10

Can be split into 4 parts:

• Asorption; -route of administration, quality of asorption, alteration in the bowel/liver
• Distribution; -effectiveness of spread throughout body, intracellular vs extracellular, tissue specific action
• Metabolism; -chemical alteration of drug
• often in the liver
• may activate or deactivate drug
• Excretion; -may be excreted unchanged or following metabolism, usually in liver (via bile) or kidney (via urine), metabolism often enhances bile/urine solubility

Question 11

What is difficult about drug development?

Answer 11

• Ardous
• Lengthy (10-12 years)
• Costly process (more than 1 billion pounds)

Question 12

What are the phases of drug development?

Answer 12

• Pre clinical development; develops basic scientific understanding of disease process (drug targets)
• Molecule screening; candiddate molecules investigated
• Pre clinical testing; animal modelling, cell culture testing
• Clinical development; 4 phases

Question 13

How may drugs be discovered?

Answer 13

• Herbalism (plant extracts)
• Serendipity (unexpected findings)
• Targeted (through understanding disease physiology)

Question 14

What are clinical trials used to establish?

Answer 14

Pre clinical studies only give limited info about drug behaviour in humans.
Used to establish:
-Appropriate dose
-Safety profile
-Does drug make people healthier?
-Does drug do what it is supposed to do?

Question 15

What is phase 1 of clinical trials used for and its characteristics?

Answer 15

• Done on healthy volunteers
• Low dose and short duration
• Closely monitored
• Strictly to monitor for toxicity and appropriate dose
• Does not provide indication of whether drug works

Question 16

What is phase 2 of clinical trials used for and its characteristics?

Answer 16

• On affected patients
• Assessment of whether drug behaves as expected eg. does a drug for hypertension reduce blood pressure?
• Does not assess treatment efficacy

Question 17

What is phase 3 of clinical trials used for and its characteristics?

Answer 17

• Large multicenter studies
• Typically assess hard long term outcomes: mortality, heart attacks, disease progression, very time consuming and expensive
• Randomised
• Placebo (or standard of care) controlled
• Patient blinding
• Investigator blinding
• Representative
• Appropriately powered

Question 18

What types of studies may be done in Phase 3?

Answer 18

-Superiority Trials; compares with established treatment (or placebo if no standard treatment) with proposed novel treatment.
Looking for significant difference between the treatments (if new one is better).

-Non-inferiority trials; compares established treatment with proposed novel treatment. Looking for there to be no difference between treatments.

Question 19

What is phase 4 of clinical trials used for and its characteristics?

Answer 19

-Consists of observations for unexpected problems associated with use of the drug;
unexpected frequency or severity of adverse effects
concerns about efficacy in clinical practice
-Often the only way to get info about real world use;
often patients with multiple health problems excluded from trials
these patients are only represented in post marketing studies
-Not well controlled - usually observational studies without randomization, blinding etc.