Pharmacology

Question 1

adrenaline doses for anaphylaxis & cardiac arrest

Answer 1

anaphylaxis: 0.5ml 1:1,000 IM (0.5mg)

cardiac arrest: 10ml 1:10,000 IV or 1ml of 1:1000 IV (1mg)

Question 2

alcohol abuse mx

Answer 2

benzodiazepines for acute withdrawal - chlordioxipoxide

disulfram - promotes abstinence. Contraindications include ischaemic heart disease and psychosis

acamprosate: weak antagonist of NMDA receptors

Nutritional support- oral thiamine

Question 3

cocaine mx

Answer 3

benzodiazepines + glyceryl trinitrate

(not B blockers! risk of unopposed alpha-mediated coronary vasospasm)

Question 4

digoxin monitoring?

Answer 4

digoxin level is not monitored routinely, except in suspected toxicity

if toxicity is suspected, digoxin concentrations should be measured within 8 to 12 hours of the last dose

Question 5

Metformin CKD caution cut offs

Answer 5

the dose should be reviewed if the creatinine is > 130 µmol/l (or eGFR < 45 ml/min) and stopped if the creatinine is > 150 µmol/l (or eGFR < 30 ml/min)

Question 6

Management of opioid dependence

Answer 6

methadone or buprenorphine as the first-line

methadone is a full agonist of the mu-opioid recepto
buprenorphine is a partial agonist of the mu-opioid receptor and an antagonist of the kappa-opioid

Question 7

Inducers of the P450 system include

Answer 7

antiepileptics: phenytoin, carbamazepine
barbiturates: phenobarbitone
rifampicin
St John’s Wort
chronic alcohol intake
griseofulvin
smoking (affects CYP1A2, reason why smokers require more aminophylline)

PC BRAS

Question 8

Inhibitors of the P450 system include

Answer 8

antibiotics: ciprofloxacin, erythromycin
isoniazid
cimetidine,omeprazole
amiodarone
allopurinol
imidazoles: ketoconazole, fluconazole
SSRIs: fluoxetine, sertraline
ritonavir
sodium valproate
acute alcohol intake
quinupristin

AO DEVICES

Question 9

Paracetamol overdose: management

Answer 9

minority of patients who present within 1 hour may benefit from activated charcoal to reduce absorption of the drug.

Acetylcysteine should be given if:
- on or above a single treatment line joining points of 100 mg/L at 4 hours and 15 mg/L at 15 hours
- there is a staggered overdose
- doubt over the time of paracetamol ingestion
- patients who present 8-24 hours after ingestion of an acute overdose of more than 150 mg/kg
- patients who present > 24 hours if they are clearly jaundiced or have hepatic tenderness, their ALT is above the upper limit of normal

acetylcysteine should be continued if the paracetamol concentration or ALT remains elevated whilst seeking specialist advice

Acetylcysteine is now infused over 1 hour - Anaphylactoid reactions -> stopping the infusion, then restarting at a slower rate.

KCL liver transplant
- Arterial pH < 7.3, 24 hours after ingestion
OR
- prothrombin time > 100 seconds
- creatinine > 300 µmol/l
- grade III or IV encephalopathy

Question 10

Tuberculosis: drug side-effects a

Answer 10

Rifampicin - hepatitis, orange secretions

Isoniazid - hepatitis, , peripheral neuropathy ( prevent with pyridoxine (Vitamin B6)

Pyrazinamide - hepatitis, gout,

Ethambutol- optic neuritis: check visual acuity before and during treatment