Clinical pharmacology and therapeutics questions
for MRCP Part 1.

A patient develops a severe, unexpected mucocutaneous reaction shortly after starting a new anticonvulsant. Which action is most appropriate regarding regulatory reporting in the UK?

1. AOnly pharmaceutical companies are permitted to report suspected reactions
2. BNo reporting is needed if the reaction is already listed in the product literature
3. CReport the suspected adverse drug reaction via the Yellow Card Scheme
4. DReporting is only required for reactions leading to death
5. EWait for definitive causality proof before reporting

Drug X requires a much lower dose than Drug Y to produce the same magnitude of effect, but both drugs can achieve the same maximum effect. Which pharmacological term best describes the difference between Drug X and Drug Y?

1. ADrug X has greater efficacy than Drug Y
2. BDrug X is more potent than Drug Y
3. CDrug X has a narrower therapeutic index
4. DDrug X is a partial agonist and Drug Y is a full agonist
5. EDrug X and Drug Y have identical pharmacodynamic properties

A patient who has taken a benzodiazepine daily for two years wishes to stop. What is the most appropriate approach to discontinuation?

1. AContinue it indefinitely, because withdrawal risks outweigh those of continued use
2. BStop abruptly, as two years of use is too short to cause dependence
3. CHalve the dose each week and stop after 2 weeks
4. DSwitch to zopiclone and stop the benzodiazepine
5. EA gradual, individualised dose reduction over weeks to months rather than abrupt cessation

A patient's phenytoin dose is increased from 250 mg to 300 mg daily because their steady-state serum level of 12 mg/L (within the 10-20 mg/L range) was considered slightly low for seizure control. Two weeks later, their level is found to be 32 mg/L, well into the toxic range, despite the dose increase being only 20%. Which explanation best accounts for this disproportionate rise?

1. APhenytoin absorption increases exponentially with dose, unrelated to metabolism
2. BNear the saturation point of hepatic metabolising enzymes, a small percentage increase in dose can produce a much larger percentage increase in steady-state concentration because elimination capacity is nearly fixed
3. CThe patient's phenytoin level was measured using an unreliable free-drug assay that overestimates total concentration
4. DFirst-order elimination predicts exactly proportional changes, so a 20% dose rise should always produce roughly a 20% concentration rise, consistent with this case
5. ERenal impairment developed acutely and is solely responsible for the rise, unrelated to hepatic saturation

During anaesthesia with sevoflurane and suxamethonium, a patient develops rapidly rising end-tidal carbon dioxide, masseter rigidity, tachycardia, hyperkalaemia and increasing core temperature despite adequate ventilation. Which medicine is the specific immediate treatment?

1. AIntravenous lipid emulsion
2. BIntravenous sodium bicarbonate as sole definitive therapy
3. CIntravenous calcium gluconate alone
4. DIntravenous dantrolene
5. EIntramuscular adrenaline