Q: 47 year old male just arrived from OR and now have accelerated hypertension, A.fib with RVR, Hyperthermia and muscle rigidity. There is a high suspicion of Neuroleptic malignant syndrome (NMS). Decision was made to use IV Dantrolene (Dantrium). Which drug should be avoided in treatment of A.fib. with RVR?
Answer: Calcium Channel Blocker (Cardizem or Verapamil)
Concomitant use of calcium channel blockers like Cardizem or Verapamil with intravenous treatment with dantrolene may lead to severe cardiovascular collapse, arrhythmias, myocardial depressions, and hyperkalemia.
Bonus Pearl: Dantrium is incompatible with D5W or normal saline! And is given by direct injection.