Basic Pharmacology Tutorial Question 2021 PDF

Preview

Summary

Great Pharmacology questions to get you up to speed with the course. Great for practice...

Description

Clinical Pharmacology Tutorials. This is your first of 15 subject tutorials in clinical pharmacology spread across Years 1 and 2. The purpose of the tutorials is to build upon your learning from pharmacology lectures to help create deeper, integrated understanding of the subject, rather than merely superficial memorisation of facts from handouts. This understanding will arise from thinking, discussing, and working out the answers to problems in tutorial sessions and also in practical classes and workshops. Most pharmacology tutorials will be based on clinical case scenarios, although initially you will need to establish some key concepts to aid understanding later. For each pharmacology tutorial: 1.

2.

You will be timetabled into one of 12 double sub-groups (from A1/A2 to C7/C8) for a tutorial covering the previous 2-4 weeks of pharmacology lectures. In 2021-22 we intend all of your pharmacology tutorials to be face-to-face in a venue at SGH or HFD with your tutor, although Covid-19 conditions may change so this can’t be guaranteed. The pharmacology tutorial team currently are: a. Prof Tony Sampson [email protected] b. Dr Tim Millar [email protected] c.

Dr Emily Swindle [email protected]

d. Dr Karl Staples [email protected] 3.

About a week before each session you’ll be emailed a list of questions, usually based on one or more patient cases, and these will also be found in the weekly resources on Blackboard. Answering these will help you participate fully in the tutorial discussion, and you may need to refer to relevant lecture handouts, websites and textbooks to familiarise yourself with the major concepts and key drug groups. We will not repeat the teaching content of lectures so you will need to prepare in advance to be able to keep up.

4.

You should also bring any queries or difficulties that have arisen in the lectures or in your reading, and these will be discussed before anything else.

5.

The same ground rules apply as for the Foundations Tutorials, such as you should engage with the work, attend the tutorial, participate actively, respect other tutees, and practise your communication skills in a confidential environment.

6.

Your attendance will be registered so you should contact me ([email protected]) to explain if you can’t attend your allocated session. It isn’t always possible to change group as they usually all take place on the same morning or afternoon and space may be limited in some venues.

7.

After the tutorial, notes of the answers will be provided for you on BB, so you will not need to take your own notes during the tutorial using laptops or other electronic devices: LECTURES ARE FOR LISTENING (and taking notes), TUTORIALS ARE FOR TALKING!

Basic Pharmacology Tutorial: Questions Aims and Outcomes The bedrock of the practice of medicine is the ability to administer drugs to benefit your patient while minimising unwanted effects. This tutorial describes how you can start to achieve this using practical examples and explanations from a molecular to whole-organ level. The aims are to enable you to: familiarise yourself with pharmacology terminology examine how drugs act at receptors to produce their effects describe how drugs can be tested without bias examine responses to increasing doses of drugs study unwanted and toxic actions

1

You will be expected to have done some preparation by reviewing your lecture notes and a pharmacology textbook (e.g. Rang & Dale; Waller & Sampson; MJ Neal) QUESTIONS. 1. What is a drug? What is a placebo? How do small amounts of a drug exert potent effects on the human body?  

Describe different types of drug targets: membrane receptors (e.g. G-protein coupled; kinase-linked); ion channels (voltage-gated or ligand-gated); metabolic enzymes; nuclear receptors. Give clinical examples of common drugs that act on each of the different types of receptor.

2. Potency and Efficacy: agonists act on their targets to produce an active response. Figure 1 (below) shows the increases in heart-rate produced by various plasma concentrations of three drug agonists (A, B and C):

(a). Why measure the increase in heart rate rather than absolute values? In what other ways could you plot these results to illustrate drug response effectively? (b). Why is it better to plot the plasma concentrations of each drug rather than the dose of drug given to the patients? What is bioavailability? (c). Plasma concentrations are shown as µM (micromolar) or µmoles/litre. List all major SI (metric) prefixes from 1012 (tera-) down to 10-12 (pico)? What is a mole of drug, what does ‘molar’ mean and how do you convert moles to grams (and back again)? What is the density of water? If the molecular weight (MW) of drug A is 200, how much is present in 10mL of a 1 µM solution? (d). Why do you think higher concentrations of a drug cause greater increases in heart rate? (e). Which is the least potent of the three drugs and what might be the explanation for this drug being less potent than the others? Estimate the EC50 values for each drug. (f). Do the drugs have different efficacies? What is the significance of the parallelism of the three log dose-response curves? 3. What are antagonists and inhibitors?

2

Figure 2 (below) shows log concentration-response curves for a single drug A. The patient was given increasing concentrations of drug A and this resulted in the curve shown on the left. The patient was then administered an antagonist of drug A called Antagonist One, and thirty minutes later the concentration-response curve to drug A was repeated (centre curve). Finally, a different antagonist (Antagonist Two) was administered, and after thirty minutes a concentration-response curve to drug A was repeated as before (right-hand curve).

(a) Explain why the curve in the presence of Antagonist One is moved to the right compared with Drug A alone. (b) Explain why the curve in the presence of Antagonist Two is moved to the right and the maximum effect obtainable is also reduced, compared with the other two curves. 4. What is selectivity of drug action and why is this important clinically? 

Give an example of selectivity of drug action and using dose-response curves explain why selectivity is dependent upon the concentration

5. What is a drug's therapeutic ratio? 6. What is drug tolerance or tachyphylaxis and how can it be tackled clinically? 7. What is meant by the concept of ‘spare receptors’? What is a partial agonist and do partial agonists have clinical uses? 8. What is a double-blind trial? What is the placebo effect? What is the ‘white coat effect’? Self-Assessment Questions: To help you monitor your own progress, there are occasional pharmacology self-assessment questions (with answers and explanations) on the weekly resources pages for Foundation module on Blackboard. Here are some examples: are they true or false? Q1. Competitive antagonists have zero efficacy Q2. Potent agonists have high ED50 (or EC50) values

T/F T/F

3

Q3. Competitive antagonists displace the agonist log D-R curve in a parallel fashion T/F Q4. Competitive antagonists always have low affinity for their receptors

T/F

Q5. Competitive antagonists are not useful therapeutically

T/F

4...