Dantrolene Verapamil

Drugs that may interact with dantrolene include clofibrate, estrogens, warfarin, and verapamil. 

CALCIUM CHANNEL BLOCKERS DANTROLENE Risk of arrhythmias when diltiazem is given with intravenous dantrolene. Risk of 1 BP, myocardial depression and hyperkalaemia when verapamil is given with intravenous dantrolene Uncertain at present Extreme caution must be exercised when administering parenteral dantrolene to patients on diltiazem or verapamil. Monitor BP and cardiac rhythm closely watch for hyperkalaemia... 

Dantrolene interacts with verapamil and with diltiazem, causing myocardial depression and cardiogenic shock (SEDA-16,199). 

The combination of dantrolene with calcium channel blockers, such as verapamil, can result in severe cardiovascular depression and hyperkalemia (SEDA-12, 113) (13,14), so that extreme care is required. 

Saltzman LS, Kates RA, Corke BC, Norfleet EA, Heath KR. Hyperkalemia and cardiovascular collapse after verapamil and dantrolene administration in stvine. Anesth Analg 1984 63(5) 473-8. 

Rubin AS, Zablocki AD. Hyperkalemia, verapamil, and dantrolene. Anesthesiology 1987 66(2) 246-9. 

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B. Dantrolene and verapamil co-administration associated with hyperkalemia (case report). 

An isolated report describes acute hyperkalaemia and cardiovascular collapse when dantrolene was given to a patient taking verapamil, but not when he was subsequently given nifedipine. Animal studies have found similar effects with the combination of dantrolene and verapamil or diltiazem, but not with nifedipine or amlodipine. 

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