Procainamide

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Procainamide
Systematic (IUPAC) name
4-amino-N-(2-diethylaminoethyl) benzamide
Identifiers
CAS number	51-06-9
ATC code	C01BA02
PubChem	4913
DrugBank	APRD00509
Chemical data
Formula	C13H21N3O
Mol. mass	235.325 g/mol
Pharmacokinetic data
Bioavailability	85% (oral)
Protein binding	15 to 20%
Metabolism	Hepatic (CYP2D6-mediated)
Half life	~2.5 to 4.5 hours
Excretion	Renal
Therapeutic considerations
Pregnancy cat.	C(US)
Legal status	POM(UK)
Routes	IV, IM, oral

Procainamide (proe-KANE-a-mide) (INN, trade names Pronestyl®, Procan®, Procanbid®) is a pharmaceutical antiarrhythmic agent used for the medical treatment of cardiac arrhythmias, classified by the Vaughan Williams classification system as class Ia.

It blocks open sodium (Na⁺) channels and prolongs the cardiac action potential (outward potassium (K⁺) currents may be blocked). This results in slowed conduction, and ultimately the decreased rate of rise of the action potential, which may result in widening of QRS on electrocardiogram (EKG). This drug is used for both supraventricular and ventricular arrhythmias. For example, it can be used to convert new-onset atrial fibrillation, though it is suboptimal for this purpose.

Procainamide is administered intravenously or orally. When administered intravenously, a loading dose should first be given, though care should be taken not to cause hypotension. Procainamide's active metabolite is N-acetyl procainamide, which is excreted by the kidneys and the renal system.

Adverse effects include rash, myalgia, hypersensitivity reactions (fever, agranulocytosis), Drug-Induced Lupus Erythematosus (paticularly in slow-acetylators), and proarrhythmic effects (e.g., torsades de pointes). Treatment with procainamide can cause antibody production against cellular components, accounting for the systemic lupus erythematosus-like adverse reactions.

v • d • e Antiarrhythmic agents (C01B)
class Ia	Ajmaline, Disopyramide, Prajmaline, Procainamide, Quinidine, Sparteine
class Ib	Aprindine, Lidocaine, Mexiletine, Tocainide
class Ic	Encainide, Flecainide, Lorcainide, Moricizine, Propafenone
class II	Propranolol, Metoprolol, Nadolol, Atenolol, Acebutolol, Pindolol see Beta blockers (C07)
class III	Amiodarone, Bretylium tosylate, Bunaftine, Dofetilide, Ibutilide, Sotalol
class IV	Verapamil, Diltiazem see Calcium channel blockers (C08)
class V	Adenosine, Atropine, Digoxin