Instead of preventing cardiac arrest, encainide and flecainide caused cardiac arrest.
Moore (1995) blames the FDA for letting encainide and flecainide onto the market.
The CAST study compared encainide and flecainide to a placebo and found excess deaths.
Early review of the data by an independent safety monitoring board revealed that 56 of 730 patients given encainide or flecainide had died from some cause or suffered a heart attack, compared with 22 of 730 patients given placebo.
Other FDA-approved anti-arrhythmics exist but are more toxic than encainide and flecainide and have not been tested for their effects on mortality.
Serum (1 mL) mixed with 0.05 mL of 3 mg/L encainide (internal standard) and 1 mL of 0.19 mol/L borate (pH 9.5) were extracted with 6 mL of 500 mL/L ethyl acetate-500 mL/L hexane.
Diazepam and midazolam would increase the apparent concentration of encainide, the internal standard used in the assay for delavirdine, indinavir, nelfinavir, ritonavir, and saquinavir.
For example, although encainide
suppresses ventricular arrhythmias, it increases mortality; gemfibrozil lowers cholesterol, but it does not reduce cardiovascular or all-cause mortality; and while calcium-channel blockers reduce blood pressure, they increase the risk of acute myocardial infarction when compared with angiotensin-converting enzyme inhibitors in hypertensive patients with diabetes.
Antiarrhythmics Amiodarone Encainide
Flecainide Mexilitine N-propylamaline Propafenone Sparteine Antidepressants Imipramine Desipramine Amitriptyline Nortriptyline Clomipramine Beta-blockers Propranolol Timolol Bufuralol Metoprolol Neuroleptics Perphenazine Thioridazine Miscellaneous Codeine Debrisoquine 4-OH amphetamine Indoramin Phenformin Table 5.
Still, SSRIs should not be administered concomitantly to patients being treated with type IC antiarrythmics (eg, encainide
, flecainide, and propafenone) because SSRIs block the metabolism of these antiarrhythmics (via inhibition of cytochrome P450 2D6), resulting in high concentrations and, possibly, treatment-emergent arrhythmias.
Encainide is a class IC antiarrhythmic agent that is used in the treatment of life-threatening ventricular arrhythmias.
The mexdetine was discontinued, and he was subsequently placed on encainide, 25 mg every 8 hours, which resulted in a dramatic reduction in the number of premature ventricular contractions.