Pharmocology

Question 1

How long should you wait before starting surgery following LMWH administration?

Answer 1

Wait 8 hours

Question 2

How long after surgery can you give a LMWH dose?

Answer 2

6 hours

Question 3

Do you prescribe insulin SC or IM?

Answer 3

SC

Question 4

Would you stop long acting insulin for a type 1 diabetic before surgery?

Answer 4

No, only short acting immediately before the operation, as they won’t be having breakfast (NBM)

Question 5

For prescribing patient’s drug chart following surgery, what is nice to include?

Answer 5

Analgesia (like paracetamol 1g QDS)

And emergency Rx for low glucose if feeling flash

Hypostop, one tablet, PO, PRN
Glucagon, 1mg, IM, PRN

Question 6

When would you put a patient on sliding scale insulin for an operation if diabetic?

Answer 6

If missing two meals or very long operation

Question 7

For fluid losses for a 70kg patient, how much would the patient lose roughly for insensible losses with or without a fever?

Answer 7

Without a fever 500mL

With a fever 1000mL

Question 8

How much potassium a day do you need?

Answer 8

1mmol/kilogram

Question 9

For a patient undergoing an operation, how long do they need to be NBM for fluid and food for?

Answer 9

Fluids- 2 hours
Food- 6 hours

(To reduce risk of aspiration)

Question 10

If you typically give 2 sweet + 1 salty, in what circumstances would you think about giving more salty (2 salty + 1 sweet)?

Answer 10

If they have upper GI losses- vomiting, NG tube etc

Question 11

What 3 types of patient require reduced fluid prescribed?

Answer 11

Cardiac failure- check lung bases, JVP, oedema
Severe CKD (oligouric)
Frailty/malnutrition (low albumin might affect distribution)

Question 12

Patient with a IHD, HTN and diabetes, has a bare metal stent following an MI. What would you do with his Aspirin and Clopidogrel before a knee op?

Answer 12

Keep aspirin

Stop clopidogrel for 7 days before

Question 13

Which conditions that are pro-thrombotic are considered high risk vs low risk of thrombosing when considering operations.

Answer 13

Low: AF, 1 remote VTE, 1 previous stroke
High: mechanical heart valves, recurrent thrombophilia, active VTE

Question 14

For which patients having an operation would you not only stop Warfarin for but also bridge them with heparin before an operation?

Answer 14

Has to be an operation with high risk of bleeding to stop it.
If high risk of thrombosis:
metallic heart valves, active VTE, thrombophilia

(not AF or 1 remote VTE or 1 stroke)

Question 15

How long before an operation do you stop anticoagulants like DOACs or Warfarin?

Answer 15

Warfarin- 5 days
DOACs- 2 days
(+ one day if in renal failure, takes longer to clear, or having an op with high risk of bleeding)

Question 16

Which antihypertensives should you stop before an operation?

Answer 16

Often just ACE inhibitors, stopping the day before

Question 17

Should you stop beta-blockers before an operation?

Answer 17

NO NO!

Most protective drug against perioperative myocardial ischaemia

Question 18

Should you stop any diabetic drugs before surgery?

Answer 18

Stop short acting insulin for meals that patient is NBM, keep long acting insulin overnight
Keep metformin generally (doesn’t lower blood sugar, just increases sensitivity unless patient will need to be NBM for a number of days)

Stop gliclazide on day of surgery (risk of low BM)

Question 19

How should you adapt someones steroid regimen prior to surgery?

Answer 19

In addition to maintenance steroids, may need to supplement with IV hydrocortisone

Question 20

Which neurology drug should be stopped two days before surgery?

Answer 20

Lithium stop 2 days before surgery.

Anticonvulsants, antidepressants, antipsychotics should be continued otherwise

Question 21

What can you give to Parkinson’s patients if they can’t take their meds?

Answer 21

NG tube or Ritagatine patches

Question 22

Why is it bad if someone on Clozapine misses their dose for 48 hours?

Answer 22

Have to re-titrate it from 25mg again up to 200mg, requires weekly blood tests again and risk of relapse

Question 23

Patient is put on Benzylpenicillin and Clarithromycin for a pneumonia. What might make you included to stop the Clarithromycin?

Answer 23

If Legonella screen comes back negative- note Clarithromycin is an enzyme inhibitor

Question 24

When would you stop Digoxin, when hypo or hyperkalaemic?

Answer 24

K+/Na+ exchanger causes K+ to go in
Digoxin blocks K+ in through exchanger
If low K+ even less K+ gets into cells