MRCPsych Pharmacology Fundamentals 2

Question 1

Which cytochrome P450 enzyme is primarily responsible for the metabolism of clozapine?

Accepted Answer

CYP1A2

Answer

CYP2D6

Answer

CYP3A4

Answer

CYP2C19

Question 2

A patient on lithium develops polyuria and polydipsia. Which mechanism best explains lithium-induced nephrogenic diabetes insipidus?

Accepted Answer

Inhibition of aquaporin-2 (AQP2) channel insertion via reduced cAMP

Answer

Blockade of ADH receptors in the collecting duct

Answer

Direct tubular damage reducing GFR

Answer

Increased aldosterone secretion

Question 3

Which pharmacokinetic parameter best predicts the risk of drug accumulation with repeated dosing?

Accepted Answer

Half-life

Answer

Volume of distribution

Answer

Bioavailability

Answer

Peak plasma concentration (Cmax)

Question 4

Mirtazapine's antihistamine properties are primarily responsible for which side effect?

Accepted Answer

Sedation and weight gain

Answer

Sexual dysfunction

Answer

QTc prolongation

Answer

Hepatotoxicity

Question 5

Which receptor mechanism underlies the therapeutic action of buspirone in generalised anxiety disorder?

Accepted Answer

5-HT1A partial agonism

Answer

GABA-A positive allosteric modulation

Answer

D2 receptor blockade

Answer

Noradrenaline reuptake inhibition

Question 6

A patient taking phenelzine eats a tyramine-rich meal and develops a hypertensive crisis. Which enzyme is phenelzine inhibiting?

Accepted Answer

Monoamine oxidase (MAO)

Answer

Catechol-O-methyltransferase (COMT)

Answer

Tyrosine hydroxylase

Answer

Dopamine beta-hydroxylase

Question 7

Which statement about the pharmacology of sodium valproate is correct?

Accepted Answer

It enhances GABA activity and inhibits sodium channels

Answer

It primarily acts by blocking dopamine D2 receptors

Answer

It is a selective serotonin reuptake inhibitor

Answer

It acts solely via NMDA receptor antagonism