procainamide hydrochloride
(redirected from Apo-Procainamide)procainamide hydrochloride
Pharmacologic class: Membrane stabilizer
Therapeutic class: Antiarrhythmic (class IA)
Pregnancy risk category C
FDA Box Warning
• Prolonged use often leads to positive antinuclear antibody (ANA) test, with or without symptoms of lupus erythematosus-like syndrome. If positive ANA titer develops, weigh benefits versus risks of continued therapy.
Action
Decreases myocardial excitability by inhibiting conduction velocity. Also depresses myocardial contractility.
Availability
Injection: 100 mg/ml, 500 mg/ml
Indications and dosages
➣ Life-threatening ventricular arrhythmias
Adults: 100 mg by slow I.V. push at a rate of 50 mg/minute, repeated q 5 minutes until arrhythmia subsides, up to a maximum advisable dosage of 1 g. Alternatively, loading dose of 500 to 600 mg by I.V. infusion over 25 to 30 minutes. With either I.V. method, maximum loading dose is 1 g. When arrhythmia subsides, give continuous I.V. infusion of 2 to 6 mg/minute. Or 50 mg/kg I.M. in divided doses q 3 to 6 hours until patient can tolerate P.O. therapy.
Dosage adjustment
• Renal impairment
Contraindications
• Hypersensitivity to drug, tartrazine, procaine, or sulfites
• Complete heart block
• Torsades de pointes
• Lupus erythematosus
Precautions
Use cautiously in:
• procaine hypersensitivity, renal impairment, ischemic heart disease, heart failure, first-degree heart block, atypical ventricular tachycardia, myasthenia gravis, systemic lupus erythematosus, cytopenia
• patients receiving other antiarrhythmics concurrently
• pregnant or breastfeeding patients
• children.
Administration
☞ Ask patient about procaine sensitivity before giving; cross-sensitivity may occur.
• For I.V. use, dilute with dextrose 5% in water.
• Administer I.V. doses with patient in supine position to avoid hypotensive effects.
• When giving by I.V. infusion, use infusion pump to ensure that drug infuses at 50 mg/minute or less.
☞ Don't leave patient's bedside during I.V. administration.
Adverse reactions
CNS: headache, dizziness, confusion, psychosis, restlessness, asthenia, depression, neuropathy, seizures
CV: hypotension, bradycardia, atrioventricular block, ventricular fibrillation, ventricular asystole, cardiovascular collapse, cardiac arrest
GI: nausea, vomiting, diarrhea, anorexia Hematologic: hemolytic anemia, agranulocytosis, thrombocytopenia, neutropenia
Skin: rash, urticaria, pruritus, flushing
Other: bitter taste, lupuslike syndrome, edema
Interactions
Drug-drug. Amiodarone: increased procainamide blood level and risk of toxicity Anticholinesterase drugs: decreased anticholinesterase effects
Antihypertensives: additive hypotension
Beta-adrenergic blockers, cimetidine, ranitidine, trimethoprim: increased procainamide blood level
Lidocaine: additive cardiodepressant action, conduction abnormalities
Neuromuscular blockers: increased skeletal muscle relaxation
Other antiarrhythmics: additive or antagonistic effects, additive toxicity
Trimethoprim: increased pharmacologic effect of procainamide
Drug-herbs. Henbane: increased anticholinergic activity
Jimsonweed: adverse cardiovascular effects
Licorice: prolonged QT interval
Drug-behaviors. Alcohol use: altered drug blood level
Patient monitoring
☞ When giving I.V., stay at patient's bedside and monitor blood pressure and ECG continuously.
☞ If ECG shows prolonged QT interval and QRS complexes, heart block, or worsening arrhythmia, stop drug therapy, run rhythm strip, and contact prescriber immediately.
• Assess blood levels of procainamide and N-acetylprocainamide (drug's active metabolite).
☞ Monitor electrolyte levels, CBC, and antinuclear antibody titers. Watch for signs and symptoms of blood dyscrasias.
• Evaluate patient for signs and symptoms of lupuslike syndrome.
Patient teaching
☞ Advise patient to immediately report cardiovascular symptoms or bleeding tendency.
• Emphasize importance of taking exactly as prescribed. Advise patient to use alarm clock to help him remember to take nighttime doses.
• Advise patient to avoid alcohol.
• Instruct patient not to take herbal remedies unless prescriber approves.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.