EM Vivas · Applied pharmacology for EM
Adrenaline concentrations and CYP3A4 storm
Clinical viva on resus drugs and high-yield interactions.
On this page
Study tools
Target exams
ACEMFRCEMABEM
Prompt
Teach the arrest versus anaphylaxis adrenaline preparations, then explain why clarithromycin can cause warfarin bleeding and simvastatin rhabdomyolysis in the same patient.
Interpretation
Reveal interpretationShowHide
Anaphylaxis: intramuscular epinephrine is first-line (WAO).[4] Ampoule concentration labels (1:1000 IM vs 1:10 000 IV) are conventional read-the-ampoule teaching, not a WAO millilitre quote. Arrest: adrenaline 1 mg IV/IO — Perkins: highly effective for ROSC (NNT 4), less so for 30-day survival (NNT 111).[3] Clarithromycin is a strong CYP3A4 inhibitor — Christensen: simvastatin/lovastatin AUC >5-fold, 14/16 ADRs rhabdomyolysis on CYP3A4-metabolised statins.[1] Recker: INR 16.8 after clarithromycin with warfarin.[2]
References5ShowHide
- [1]Hougaard Christensen MM, et al. Interaction potential between clarithromycin and individual statins-A systematic review. Basic Clin Pharmacol Toxicol, 2020.PMID 31628882
- [2]Recker MW, Kier KL. Potential interaction between clarithromycin and warfarin Ann Pharmacother, 1997.PMID 9296238
- [3]Perkins GD, Couper K. Improving vasopressor use in cardiac arrest Crit Care, 2023.PMID 36864469
- [4]Cardona V, Ansotegui IJ, Ebisawa M, et al. World allergy organization anaphylaxis guidance 2020 World Allergy Organ J, 2020.PMID 33204386
- [5]Kudenchuk PJ, Cobb LA, Copass MK, et al. Amiodarone for resuscitation after out-of-hospital cardiac arrest due to ventricular fibrillation N Engl J Med, 1999.PMID 10486418