Prescription review

Question 1

When to stop COCP and HRT before surgery?

Answer 1

4 weeks (due to risk of thromboembolism)

Question 2

When to stop ACEi/ARBs before surgery?

Answer 2

24hrs (due to profound hypotension if used with general anaesthetic)

Question 3

When to stop lithium before surgery?

Answer 3

24hrs before MAJOR surgery (can be continued in minor ops)

Question 4

When to stop K-sparing diuretics like spironolactone before surgery?

Answer 4

On MORNING of surgery (as it can cause hyperkalaemia if renal perfusion drops during surgery)

Question 5

When should warfarin be stopped pre-op?

- What should be prescribed in interim?

Answer 5

5 days.

LMWH should be prescribed in interim

Question 6

How many days pre-op should you stop DOACs (e.g. apixaban)?

Answer 6

48hrs

Question 7

Is aspirin stopped pre-op?

Answer 7

Up to 1 week before (as with all anti-platelets)

Question 8

When to stop insulin pre-op?

Answer 8

Avoid morning dose

Question 9

When to stop oral hypoglycaemics pre-op?

Answer 9

Avoid on day of operation

Question 10

When to stop metformin?

Answer 10

Avoid for 2 days after surgery due to risk of lactic acidosi

Question 11

Steroid rules peri-operatively

Answer 11

1. If NBM, convert oral steroids to IV

2. Increase dose of steroids pre-op

Question 12

Hyperkalaemia causes

Answer 12

SHANT
o	Spironolactone
o	Heparin
o	ACEi/ARB
o	NSAIDs
o	Tacrolimus

Question 13

Hyponatraemia causes

Answer 13

SAD
o SSRIs
o Anticonvulsants
o Diuretics

Question 14

Hyperglycaemia?

Answer 14

CAT-B
o	Corticosteroids
o	Atypical antipsychotics (olanzapine, risperidone)
o	Thiazide diuretics & Tacrolimus
o	BBs

Question 15

Hypoglycaemia?

Answer 15

The diabetic drugs, EXCEPT metformin! Metformin DOES NOT cause hypoglycaemia – don’t let them trick you.

Question 16

Which drugs have doses in mcg?

Answer 16

Digoxin and levothyroxine (watch out in dosing error Qs)

Question 17

Which drugs are given weekly?

Answer 17

Methotrexate and alendronic acid

Question 18

If you see a drug given in grams, double check it’s correct

Answer 18

This is because it’s relatively rare and could come up in a drug dosing error Q

Question 19

Why might some anticoagulants/antiplatelets be switched to a heparin peri-operatively?

Answer 19

as it’s much easier to reverse (via protamine sulphate)

Question 20

Drugs causing confusion (and thus falls)

Answer 20

• Drugs with anti-cholinergic effects (e.g. antidepressants)
• Z drugs (e.g. zoplicone and benzodiazepine)
• Steroids (e.g. prednisolone)
• Anti-hypertensives (particularly diuretics –> postural drop)

Question 21

Which drugs cause long Qtc?

Answer 21

• Anti-psychotics
• Anti-depressants
• Anti-emetics
• Beta blockers (e.g. sotalol)
• Potassium channel blockers (e.g. amiodarone)
• Sodium channel blockers (e.g. flecainide)
• Certain antibiotics (e.g. ciprofloxacin, erythromycin)

Question 22

P450 enzyme inducers

Answer 22

SICKFACE.COM

• Sodium valproate
• Isoniazid
• Cimetidine
• Ketoconazole
• Fluconazole
• Alcohol (binge)
• Chloramphenicol
• Erythromycin
• Sulphonamides
• Ciprofloaxacin
• Omeprazole
• Metronidazole

Question 23

P450 enzyme inhibitors

Answer 23

SCRAP GPS

• St John’s Wart
• Carbamazepine
• Rifampicin
• Alcohol (chronic)
• Phenytoin
• Griseofulvin
• Phenobarbitone
• Sulphonylureas

Question 24

When to stop metformin?

Answer 24

When eGFR <30.

Question 25

Allopurinol can accumulate in renal dysfunction

Answer 25

BNF advises max daily dose of 100mg until renal function improves

Question 26

In UTI questions, when should you avoid nitrofurantoin?

Answer 26

If eGFR <45. Use trimethoprim instead!

Question 27

A small rise in creatinine (<20%) is to be expected when starting an ACEi

Answer 27

Thus does not require Ix or change in prescription

Question 28

when else to stop metformin?

Answer 28

the day before surgery