Pharmocology Flashcards
How long should you wait before starting surgery following LMWH administration?
Wait 8 hours
How long after surgery can you give a LMWH dose?
6 hours
Do you prescribe insulin SC or IM?
SC
Would you stop long acting insulin for a type 1 diabetic before surgery?
No, only short acting immediately before the operation, as they won’t be having breakfast (NBM)
For prescribing patient’s drug chart following surgery, what is nice to include?
Analgesia (like paracetamol 1g QDS)
And emergency Rx for low glucose if feeling flash
Hypostop, one tablet, PO, PRN
Glucagon, 1mg, IM, PRN
When would you put a patient on sliding scale insulin for an operation if diabetic?
If missing two meals or very long operation
For fluid losses for a 70kg patient, how much would the patient lose roughly for insensible losses with or without a fever?
Without a fever 500mL
With a fever 1000mL
How much potassium a day do you need?
1mmol/kilogram
For a patient undergoing an operation, how long do they need to be NBM for fluid and food for?
Fluids- 2 hours
Food- 6 hours
(To reduce risk of aspiration)
If you typically give 2 sweet + 1 salty, in what circumstances would you think about giving more salty (2 salty + 1 sweet)?
If they have upper GI losses- vomiting, NG tube etc
What 3 types of patient require reduced fluid prescribed?
Cardiac failure- check lung bases, JVP, oedema
Severe CKD (oligouric)
Frailty/malnutrition (low albumin might affect distribution)
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?
Keep aspirin
Stop clopidogrel for 7 days before
Which conditions that are pro-thrombotic are considered high risk vs low risk of thrombosing when considering operations.
Low: AF, 1 remote VTE, 1 previous stroke
High: mechanical heart valves, recurrent thrombophilia, active VTE
For which patients having an operation would you not only stop Warfarin for but also bridge them with heparin before an operation?
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)
How long before an operation do you stop anticoagulants like DOACs or Warfarin?
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)
Which antihypertensives should you stop before an operation?
Often just ACE inhibitors, stopping the day before
Should you stop beta-blockers before an operation?
NO NO!
Most protective drug against perioperative myocardial ischaemia
Should you stop any diabetic drugs before surgery?
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)
How should you adapt someones steroid regimen prior to surgery?
In addition to maintenance steroids, may need to supplement with IV hydrocortisone
Which neurology drug should be stopped two days before surgery?
Lithium stop 2 days before surgery.
Anticonvulsants, antidepressants, antipsychotics should be continued otherwise
What can you give to Parkinson’s patients if they can’t take their meds?
NG tube or Ritagatine patches
Why is it bad if someone on Clozapine misses their dose for 48 hours?
Have to re-titrate it from 25mg again up to 200mg, requires weekly blood tests again and risk of relapse
Patient is put on Benzylpenicillin and Clarithromycin for a pneumonia. What might make you included to stop the Clarithromycin?
If Legonella screen comes back negative- note Clarithromycin is an enzyme inhibitor
When would you stop Digoxin, when hypo or hyperkalaemic?
K+/Na+ exchanger causes K+ to go in
Digoxin blocks K+ in through exchanger
If low K+ even less K+ gets into cells
