Pharmacology

Question 1

What electrolyte abnormalities precipitate digoxin toxicity?

Answer 1

MOST COMMONLY: hypokalaemia

Others:
Hypomagnesaemia
Hypercalcaemia
Hypernatraemia

Question 2

How does MI management differ in those who have cocaine-induced MI?

Answer 2

Benzodiazepines (for coronary artery vasospasm)

Question 3

What are the clinical features of organophosphate poisoning?

Answer 3

(mnemonic = SLUD)
Salivation
Lacrimation
Urination
Defecation/diarrhoea
cardiovascular: hypotension, bradycardia
also: small pupils, muscle fasciculation

Question 4

What is the management of organophosphate poisoning?

Answer 4

Atropine

Question 5

What are the features of carbon monoxide toxicity?

Answer 5

headache: 90% of cases
nausea and vomiting: 50%
vertigo: 50%
confusion: 30%
subjective weakness: 20%
severe toxicity: ‘pink’ skin and mucosae, hyperpyrexia, arrhythmias, extrapyramidal features, coma, death

Question 6

What antibiotic may lower seizure threshold?

Answer 6

Quinolones e.g. Ciprofloxacin

Question 7

When to avoid taking macrolides and why?

Answer 7

statins should be stopped whilst taking a course of macrolides. Macrolides inhibit the cytochrome P450 isoenzyme CYP3A4 that metabolises statins. Taking macrolides concurrently with statins significantly increases the risk of myopathy and rhabdomyolysis.

Question 8

What are main side effects of amlodipine?

Answer 8

Headache, flushing and ankle oedema

Question 9

What is the consequences of allopurinol and azathioprine use?

Answer 9

Azathioprine is a prodrug, meaning it is metabolised to its active form, 6-mercaptopurine, which causes immunosuppression (preventing kidney rejection in this patient). The active 6-mercaptopurine is subsequently metabolised by xanthine oxidase to inactive this uric acid which is excreted. As allopurinol inhibits xanthine oxidase, the combination of the two drugs can lead to excessive myelosuppression and therefore increase the risk of neutropenic sepsis.

Question 10

What is the consequences of allopurinol and cyclophosphamide use?

Answer 10

allopurinol reduces renal clearance, therefore may cause marrow toxicity

Question 11

What is the consequences of allopurinol and Theophylline use?

Answer 11

allopurinol causes an increase in plasma concentration of theophylline by inhibiting its breakdown

Question 12

What are the causes of drug-induced urinary retention?

Answer 12

1) tricyclic antidepressants e.g. amitriptyline
2) anticholinergics e.g. antipsychotics, antihistamines
3) opioids
4) NSAIDs
5) disopyramide

Question 13

What is the use of sidenafil in neonates?

Answer 13

To treat pulmonary hypertension?

Question 14

What are common adverse effects of aminoglycosides?

Answer 14

Ototoxicity and nephrotoxicity

Question 15

What is the mechanism of action of aspirin?

Answer 15

Aspirin is a non reversible COX 1 and 2 inhibitor

Question 16

What is the mechanism of action of finasteride?

Answer 16

5 alpha reductase inhibitor which converts testosterone into DHT

Question 17

What is the most important factor for considering liver transplant after paracetamol OD?

Answer 17

arterial pH is the single most important factor according to the King’s College Hospital criteria for liver transplantation.

Question 18

What to do if GI side effects of metformin?

Answer 18

Switch to MR metformin before trying second-line drug

Question 19

What is the management of salicylate OD?

Answer 19

1) Charcoal (if within 1 hr)
2) urinary alkalinization with intravenous sodium bicarbonate
3) haemodialysis

Question 20

What are the signs and symptoms of lithium toxicity?

Answer 20

Diarrhoea, vomiting, abdominal pain, coarse tremor, weakness, seizures, muscle twitches and blurred vision