Clinical Pharmacology, Therapeutics and Toxicology

Question 1

what is the drug in anti-freeze

Answer 1

ethylene glycol

Question 2

features of ethylene glycol poisoning

Answer 2

stage 1: similar to alcohol, confusion, ataxia, slurred speech

2: metabolic acidosis with high anion gap and high osmolar gap. Also tachycardia and hypertension
3: acute renal failure

Question 3

Mx of ethylene glycol poisoning

Answer 3

fomepizole (alcohol dehydrogenase inhibitor)
used to use alcohol
haemodialysis in refractory cases

Question 4

role of somatostatin

Answer 4

inhibits GH, glucagon and insulin release

Question 5

indications for octreotide

Answer 5

acute variceal haemorrhage 
acromegaly
carcinoid syndrome (flushing, diarrhoea, restrictive cardiomyopathy)
post pancreatic surgery
VIPomas
refractory diarrhoea

Question 6

features of carcinoid syndrome

Answer 6

flushing
diarrhoea
restrictive cardiomyopathy

secondary to carcinoid tumours (neuroendocrine)

Question 7

Side effects of ciclosporin

Answer 7

everything increased

BP, fluid, gums, hair, K, glucose

Question 8

drugs with zero-order kinetics:

Answer 8

metabolism independent of reactant concentration
phenytoin
salicylates
heparin
ethanol

Question 9

how common is a deficiency of hepatic N-acetyltransferase?

which drugs are affected by this?

Answer 9

50% PISHD
Procainamide (1a antiarrhythmic)
Isoniazid
Sulfasalazine
Hydralazine (vascular smooth m relaxant)
Dapsone

Question 10

effect of macrolides on other medications

Answer 10

macrolides (erythromycin, clarithromycin, azithromycin)
macrolides inhibit P450 enzymes which metabolise statins, significantly increasing risk of myopathy and rhabdomyolysis therefore stop statins whilst on macrolides

Question 11

mechanism of action of bezafibrate

SE

Answer 11

PPAR-alpha agonist, increasing lipoprotein lipase expression.
SE: myositis, cholestasis, pruritis

Question 12

ECG changes of TCA overdose

Answer 12

sinus tachy
wide QRS
prolonged QT interval

Question 13

how long do you have to take steroids for before needing osteoporosis prophylaxis

Answer 13

prednisolone 7.5mg or equivalent for >3months

Question 14

how long may it take for finasteride to work?
mechanism of action
SE

Answer 14

can be up to 6 months
5-alpha reductase inhibitors (blocks testosterone -> DHT)
SE: ED, decreased libido, ejaculation problems, gynaecomastia

Question 15

Mx of Beta blocker OD

Answer 15

atropine and glucagon
glucagon is positively ionotropic and decreases renal vascular resistance
If above fails then pacing

Question 16

adverse features of cocaine use

Answer 16

Cardiac: MI, tachy or brady, HTN, QRS widening and QT prolongation, aortic dissection
Neuro: seizures, hypertonia, hyperreflexia, mydriasis
psych: agitation, psychosis, hallucinations
other: hyperthermia, metabolic acidosis, rhabdomyolysis

Question 17

Cocaine
Mechanism of action
Mx

Answer 17

D, NA, and 5HT reuptake inhibitor
Mx: Benzos
BZD + GTN (if chest pain, PCI if MI)
BDZ + sodium nitroprusside (if HTN)

Question 18

features of paracetamol OD

Answer 18

n&v

24 hrs later: RUQ pain, jaundice, encephalopathy

Question 19

causes of gingival hyperplasia

Answer 19

ciclosporin
calcium channel blockers
phenytoin
AML

Question 20

Mx of cyanide poisoning

Answer 20

IV hydroxycobalamin
Dicobalt edetate
inhaled amyl nitrite, IV sodium nitrite (oxidises Fe2 to Fe3, forming methaemoglobin which binds to cyanide)
thiosulphate also used to metabolise cyanide

Question 21

What is the mode of action of ciprofloxacin?

Answer 21

Bacterial DNA gyrase inhibitors.

Question 22

What is the mechanism of action of trimethoprim

Answer 22

bacterial folate synthesis inhibitor