Procainamide HCl

A to Z Drug Facts

(pro-CANE-uh-mide HIGH-droe-KLOR-ide)

Procanbid, Pronestyl, Pronestyl-SR,  Apo-Procainamide, Procan SR

Class: Antiarrhythmic

 Action Increases effective refractory period of atria and bundle of His-Purkinje system; reduces impulse conduction velocity and myocardial excitability in atria, Purkinje fibers and ventricles.

 Indications Treatment of documented ventricular arrhythmias that are life threatening.

 Contraindications Complete heart block; idiosyncratic hypersensitivity; lupus erythematosus; torsade de pointes.

 Route/Dosage

ADULTS: PO 50 mg/kg/day in divided doses (q 3 hr for regular release; q 6 hr for sustained release). IV 20 mg/min for 25–30 min as loading dose, then 2 to 6 mg/min for maintenance. IM 50 mg/kg/day in divided doses q 3 to 6 hr until oral therapy is possible. CHILDREN: Safety not established. Following doses have been used: PO 15 to 50 mg/kg/day in divided doses q 3 to 6 hr maximum of 4 g/day; IM 20 to 30 mg/kg/day in divided doses q 4 to 6 hr, maximum 4 g/day; IV 3 to 6 mg/kg/dose over 5 min for loading dose, then 20 to 80 mcg/kg/min continuous infusion (maximum 100 mg/dose or 2 g/day).

 Interactions

Amiodarone, cimetidine, trimethoprim: May increase procainamide and NAPA concentrations.

 Lab Test Interferences None well documented.

 Adverse Reactions

CV: Proarrhythmic effects; hypotension. CNS: Dizziness; weakness; depression; psychosis with hallucinations. DERM: Angioneurotic edema; urticaria; pruritus; flushing; rash. EENT: Bitter taste. GI: Nausea; vomiting; anorexia; abdominal pain. HEMA: Neutropenia; thrombocytopenia; hemolytic anemia; agranulocytosis. OTHER: Lupus erythematosus–like syndrome.

 Precautions

Pregnancy: Category C. Lactation: Excreted in breast milk. Children: Safety and efficacy not established. Special-risk patients: Elderly patients and patients with renal, hepatic or cardiac insufficiency will require smaller or less frequent doses. Individual dosage adjustment will be necessary. Asymptomatic PVCs: Avoid use of product in treatment of patients with this condition. Blood dyscrasias: Agranulocytosis, bone marrow depression, neutropenia, hypoplastic anemia, and thrombocytopenia have been reported; monitor carefully. Cardiovascular effects: Procainamide has proarrhythmic effects. May cause or aggravate CHF or produce severe hypotension especially in patients with CHF, acute ischemic heart disease, or cardiomyopathy. Complete heart block: Do not administer to patients with complete heart block because of effects in suppressing nodal or ventricular pacemakers and hazard of asystole. Concurrent antiarrhythmic agents: May see enhanced prolongation of conduction or depression of contractility and hypotension. Digitalis intoxication: Use with caution treating arrhythmias associated with digitalis intoxication. First-degree heart block: Use with caution if first degree heart block develops during procainamide therapy. Myasthenia gravis: Patients may experience increase of muscle weakness. Observe closely. Renal impairment: Individual dose adjustment may be necessary. Predigitalization for atrial flutter or fibrillation: Cardiovert or digitalize patient prior to procainamide therapy to avoid enhancement of atrioventricular conduction. Sulfite sensitivity: Parenteral forms contain sulfites. Tartrazine sensitivity: Some tablet forms contain tartrazine. Antinuclear antibodies (ANA): Approximately 50% of patients will develop ANA within 2 to 18 mo of starting therapy. Some of these patients may develop lupus-like syndrome.

 Administration/Storage

• Give sustained-release forms whole. Do not crush or allow patient to bite or chew them.
• Digitalize or cardiovert patients with atrial flutter or fibrillation as prescribed prior to administration.
• Prepare IV infusion solution using D5W. Use controlled infusion device.
• IV solutions may turn slightly yellow or light amber on standing but potency is not affected.
• For direct IV injection, do not exceed maximal IV rate of 50 mg/min and do not give more than 100 mg in any 5-min period.
• Wait 3 to 4 hr after last IV dose before first oral dose.
• IV solutions may be stored at room temperature for 24 hr or for 7 days if refrigerated. Discard IV infusion solutions that are darker than light amber.
• Store oral dosage forms at room temperature in tightly closed container.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Repeat ECG as ordered.
• Be aware that patients with decreased renal function and elderly patients will metabolize drug more slowly.
• Monitor ECG and blood pressure regularly during parenteral administration.
• Monitor muscle weakness in patients with myasthenia gravis.
• Monitor results of complete blood cell counts (including white blood cell differential and platelet count) weekly during first 3 months of therapy and periodically thereafter as well as at any time patient develops signs of infection, bruising, or bleeding.
• Monitor procainamide and NAPA levels as ordered.
• Report diarrhea, vomiting, anorexia, abdominal pain, dizziness, or altered mental status to physician.
• In prolonged therapy observe for lupus erythematosus—like syndrome with arthralgia, pleural, or abdominal pain, and possible fever, chills, myalgia, pericarditis, pleural effusion, arthritis, or skin lesions and report to physician.

 Patient/Family Education

• Tell patient to take medication with full glass of water.
• Caution patient not to crush or chew sustained-release capsules.
• Explain that this medication should be taken throughout 24-hr period.
• Explain importance of informing other physicians or dentist about therapy before surgical or dental procedures.
• Emphasize importance of drug compliance. Caution patient not to make up for missed doses.
• Instruct patient to report the following symptoms to physician immediately: Difficulty breathing, pounding or irregular heartbeat, joint pain, fever, chills, skin rash or continued dizziness.
• Explain that diarrhea, nausea, dizziness, or loss of appetite may occur and to contact physician if symptoms are bothersome.
• Advise patient that drug may cause dizziness and to use caution when driving or performing other tasks requiring mental alertness.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts