Formative Assessment

Question 1

What pharmacodynamic properties is a competitive reeptor antagonist most likely to display?

Answer 1

Zero efficacy and moderate affinity

Question 2

What form of drug antagonism would describe the ability of adrenaline to reduce the effects of mast cell derived histamine during an anaphylactic response?

Answer 2

Physiological Antagonism

Question 3

A section of vascular smooth muscle is placed in an organ bath and stimulated with increasing doses of noradrenaline. A graph of the relationship between dose and response (effect) wherein all possible degrees of response between minimum detectable response and a maximum response is produced. The dose response curve is then repeated with FIVE different drug regimens. From the list below, please select which possibility could NEVER induce a maximal response:

A. Noradrenalineplus Phentolamine (non selective alpha receptor antagonist)

B.Adrenaline (agonist with lower affinity for areceptors)

C.Clonidine (partial agonist)

D.Noradrenaline plus Propranolol (non-selective beta receptor antagonist)

E.Phenylephrine (a1-selective agonist)

Answer 3

Clonidine (partial agonist)

Question 4

Thirty minutes after administration, blood levels of a drug are higher in the hepatic portal venous system than in the major arteries (systemic blood levels). Which route of administration was utilised for this drug?

Answer 4

ORAL

All routes of administration result with the drug in a venous system

However, with oral, it is the venous system leading away from the GI tract, which is the hepatic portal venous system

Question 5

Drug metabolism often reduces the lipid solubility of drugs and thus makes the drug easier to excrete. Why is this so?

Answer 5

Reduces reabsorptionin the kidney

Question 6

The figure below shows a Phase 1 metabolic reaction. What type of Phase 1 reaction has taken place in this figure?

Answer 6

Reduction

Question 7

What neurones are associated with noradrenaline neurosecretion?

Answer 7

Postganglionic sympathetic neurones innervating the kidney

Question 8

What effects can be attributed to anti-cholinesterase poisoning?

Answer 8

Increased parasympathetic effects such as increased secretions

This is because ACh is not being broken down

Question 9

How do muscarinic receptor antagonists influence function within the striatum and thus improve the symptoms of Parkinson’s?

Answer 9

Increased dopamine receptor activation

Parkinson’s

• Loss of dopaminergic neuronesfrom sub nigrato striatum
• Muscarinic receptors physiologically inhibit D1 receptor
• D1 would be on cell body on striatum which respond to dopamine from sub nigra
• By blocking that receptor, you increase the responsiveness if the D1 receptors

Question 10

A 54-year-old man is admitted to Accident & Emergency suffering an anaphylactic reaction after being stung by a wasp whilst out rambling. The registrar finds a bottle of b-blocker tablets in his pocket. What clinical feature of anaphylaxis could be worsened by these tablets?

Answer 10

Bronchospasm

Beta blockers block receptors in heart, lungs, liver especially

Question 11

A 75-year-old man is diagnosed with glaucoma and is treated with a α1 selective adrenoceptoragonist. The therapeutic effects of the drug are partly due to which functions?

Answer 11

Vasoconstriction of ciliarybody arterioles

• Reduces blood flow to ciliary bodies

[Accomodation is to do with the lens, which doesn’t really impact upon glaucoma]

Question 12

The figure below shows the response associated with a 10mg/kg dose of drug A (represents the ED50 for drug A). If you repeated this dose of drug A in the presence of a fixed dose of the relevant competitive receptor antagonist, where would you expect the “x” to be placed on the graph above in comparison to its current position?

Answer 12

Directly below

Can’t shift right or left because you are not changing the dose