PLAB 1 Pharmacology & Prescribing

Question 1

A patient with atrial fibrillation is started on warfarin. Which of the following drugs, if added, would most significantly increase the risk of bleeding by inhibiting warfarin metabolism?

Accepted Answer

Fluconazole

Answer

Rifampicin

Answer

Carbamazepine

Answer

St John's Wort

Question 2

A 70-year-old woman with heart failure is started on spironolactone. Which electrolyte abnormality must be monitored closely?

Accepted Answer

Hyperkalaemia

Answer

Hypokalaemia

Answer

Hyponatraemia

Answer

Hypercalcaemia

Question 3

A patient with type 2 diabetes has an eGFR of 25 ml/min/1.73m². Which diabetes medication must be stopped or dose-reduced due to risk of lactic acidosis?

Accepted Answer

Metformin

Answer

Sitagliptin

Answer

Gliclazide

Answer

Insulin

Question 4

A 25-year-old woman presents 2 hours after taking 20 paracetamol tablets (10g). She is asymptomatic. Serum paracetamol level is above the treatment line on the nomogram. What is the most appropriate treatment?

Accepted Answer

IV N-acetylcysteine (NAC)

Answer

Activated charcoal only

Answer

Oral methionine

Answer

Supportive care and monitoring only

Question 5

Which antibiotic is contraindicated in pregnant women due to the risk of 'grey baby syndrome' in neonates?

Accepted Answer

Chloramphenicol

Answer

Amoxicillin

Answer

Erythromycin

Answer

Cefalexin

Question 6

A patient on warfarin develops a DVT and is found to have a supratherapeutic INR of 8.5 with minor bleeding from the gums. What is the most appropriate management?

Accepted Answer

Stop warfarin and give oral vitamin K 1–2mg; review in 24 hours

Answer

Stop warfarin, give IV vitamin K 5mg, and transfuse FFP

Answer

Continue warfarin and observe

Answer

Stop warfarin and give idarucizumab

A patient with atrial fibrillation is started on warfarin.Which of the following drugs, if added, would most significantly increase the risk of bleeding by inhibiting warfarin metabolism?

A patient with atrial fibrillation is started on warfarin.
Which of the following drugs, if added, would most significantly increase the risk of bleeding by inhibiting warfarin metabolism?