Possible Interaction: Amiodarone and Quinidine

“Agents that have pharmacokinetic interactions, such as quinidine and amiodarone , should not be given together because this combination may be associated with a considerable proarrhythmic effect.”

“ Amiodarone has also been shown to interact with other antiarrhythmic agents such as quinidine and procainamide.”

“Given the predictable pharmacokinetics, it does not require regular monitoring.9 The dose should be reduced by about 1/4 with amiodarone intake, whereas quinidine should be avoided (Pradaxa® insert).”

“Co-administration of drugs like p-glycoprotein inhibitors amiodarone , verapamil, quinidine and ciclosporin) can increase serum digoxin concentration between 20% and 60%.9 Electrolyte disturbances like hypokalaemia and hypomagnesaemia, induced by diuretic agents and hypercalcaemia can also increase digoxin toxicity.”

“ Amiodarone increased the VT cycle length more than quinidine (85 vs 121 ms, p < 0.05).”

“It increased from 323±39 to 423±84 msec (n = 11, p < 0.01) by adding encainide to amiodarone therapy, and it showed a tendency to lengthen when quinidine was added to amiodarone (from 373 ± 77 to 425 ± 58 msec; n = 10, NS).”

“ Amiodarone in combination with quinidine prevented the induction of ventricular fibrillation and proved effective during a 3-year follow-up period.”

“Clinically significant drug interactions have been observed with amiodarone and warfarin, digoxin, quinidine and procainamide.”

“Clinical toxicity occasionally occurred with the increase in serum levels of quinidine and procainamide, and the dose of these drugs should be decreased when amiodarone is administered concurrently.”

“The patient was treated with oral amiodarone which was unsuccessful until combined with quinidine ; this regimen has suppressed recurrence of VT during a four‐month period of follow‐up.”