Section 8: Data interpretation Flashcards
What drug combination can cause an elevated CK and LDH?
The combination of a statin with clarithromycin (macrolide) can result in increased exposure to statin, leading to rhabdomyolysis
Patient on warfarin presents with INR of 7.1 with a minor bleed - what do you do?
Stop warfarin. Give PO vit K. Wait for INR to normalise. Start warfarin again at 10-15% dose.
Patient on 5mg apixaban BD has a serum creatinine of 135umol/l. She weighs 59 kg. How do you manage this prescription?
Reduce dose to 2.5mg BD. Patient meets 2 out of 3 criteria for this at least (cr >133 and <61kg)
1) At least 80yo
2) Cr >133
3) <61kg
What drugs can cause agranulocytosis?
Clozapine. Carbimazole. Carbimazepine. Methotrexate. Azathioprine. Sulfasalazine. Quinine.
What is the target range of TSH?
0.5-5mIU/L - adjust levothyroxine dose accordingly in hypothyroidism
What ECG changes do you see in hyperkalemia?
Tall tented T waves, prolonged PR, unusual QRS morphology
A patient on warfarin for AF has an INR of 6.1 but no signs of bleeding. What is the appropriate action to take?
Omit two doses of warfarin and recheck INR.
What will happen to a patient’s INR if they are on warfarin and started on erythromycin?
Erythromycin is an enzyme inhibitor, which will reduce clearance and increase plasma level of warfarin. This will cause raised INR levels.
Patient appears spetic with neutrophils of 0.7. How would you treat?
Piperacillin with tazobactam + gentamicin, both IV.
What drugs can cause hyponatremia?
Furosemide, spironolactone, acetazolamide, carbamazepine, SSRIs, TCAs
Patient on PO morphine now has raised creatinine and K+ alongside oliguria. What do you do?
Switch to PO oxycodone, preferred in renal impairment. 10mg morphine sulfate = 5mg oxycodone.
A patient vomiting blood repeatedly with a BP of 82/40mm Hg is on regular warfarin and has an INR >10. What do you do?
If patient is bleeding and shocked, omit warfarin and rapidly reverse effects with dried prothrombin complex OR fresh frozen plasma.
Patient on amiodarone has a raised serum T4 and decreased TSH. What do you do?
Withhold initially to achieve control. Following this, if amiodarone still required consider restarting alongside anti thyroid medications like carbimazole.
A patient post-AKI has been on fluid replacement over the past 24h. You notice urine output of 250ml/ hour and negative fluid balance on the chart, with 1L lost every 4 hours. How do you manage this?
This may reflect a ‘polyuric phase’ following fluid replacement (>200ml/h). Prescribe 1L 5% dextrose (or 0.9% NaCl) with 20mmol KCl over 4 hours to match their output.
A patient on regular phenytoin monotherapy 150mg OD for epilepsy has a phenytoin level of 22 (40-80). How do you manage this patient?
Increase phenytoin to 175mg OD. Do not stip antiepileptics abruptly unless patient is toxic. Dose should be increased slowly, e.g. by increments of 25mg.
