Phenytoin Capsules and Procainamide Hydrochloride

• Generic Name: phenytoin
• Dosage Forms: capsule, extended release
• Other Brand Names: Dilantin, Phenytek, Dilantin Infatabs, Phenytoin Sodium, Prompt

Phenytoin is an anti-epileptic drug, also called an anticonvulsant. Phenytoin works by slowing down impulses in the brain that cause seizures.

Phenytoin is used to control seizures. It does not treat all types of seizures, and your doctor will determine if it is the right medicine for you.

• Generic Name: procainamide
• Dosage Forms: n.a.
• Other Brand Names: Pronestyl, Procan SR, Pronestyl-SR, Procanbid

Comparably effective to quinidine for atrial or ventricular arrhythmias; choice based on pharmacokinetics and adverse effect profile.

Treatment of ventricular arrhythmias (e.g., sustained VT) that in the judgment of the clinician are life-threatening, but usually not the antiarrhythmic of first choice.

Not a first-line drug of choice during cardiac arrest, but may be used for treatment of wide-complex tachycardias in the periarrest period; included in current ACLS treatment guidelines for adult and pediatric tachycardia.

May be used in the treatment of sustained, stable monomorphic VT not associated with angina, pulmonary edema, or hypotension (BP <90 mm Hg) in patients with preserved ventricular function.

Some experts recommend revascularization and β-blockade followed by IV antiarrhythmic drugs, such as procainamide or amiodarone, for patients with recurrent or incessant polymorphic VT due to acute myocardial ischemia.

Because of procainamide's arrhythmogenic potential, lack of evidence for improved survival for class I antiarrhythmic agents, and risk of serious, potentially fatal adverse hematologic effects (see Boxed Warning), particularly leukopenia or agranulocytosis, use for less severe arrhythmias not recommended.

Reserve for suppression and prevention of documented life-threatening ventricular arrhythmias in carefully selected patients in whom the benefits of procainamide therapy outweigh the possible risks.

Avoid treatment of asymptomatic VPCs.

Initiate procainamide therapy only in a hospital setting.

Has been used for treatment of various supraventricular tachycardias (SVTs); because of higher risk of toxicity and proarrhythmic effects, antiarrhythmic agents generally reserved for patients who do not respond to or cannot be treated with AV nodal blocking agents (β-adrenergic blocking agents, verapamil, diltiazem).

May be useful in patients with preexcited atrial fibrillation and rapid ventricular response associated with Wolff-Parkinson-White syndrome; however, direct-current cardioversion is treatment of choice when patient is hemodynamically compromised.

Also has been used for treatment of junctional tachycardia; however, more limited role and generally considered only when IV β-adrenergic blocking agents are ineffective.

Used parenterally (preferably IM) in the treatment of arrhythmias that occur during surgery and anesthesia.

IV procainamide has been used effectively in the treatment of malignant hyperthermia.