Procainamide overdosage

Procainamide
PROCAINAMIDE HYDROCHLORIDE® FDA Package Insert
Indications and Usage
Dosage and Administration
Dosage Forms and Strengths
Contraindications
Warnings and Precautions
Adverse Reactions
Drug Interactions
Use in Specific Populations
Overdosage
Description
Clinical Pharmacology
Nonclinical Toxicology
Clinical Studies
How Supplied/Storage and Handling
Patient Counseling Information
Labels and Packages
Clinical Trials on Procainamide
ClinicalTrials.gov

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sheng Shi, M.D. [2]

Overdosage

Progressive widening of the QRS complex, prolonged Q-T and P-R intervals, lowering of the R and T waves, as well as increasing A-V block, may be seen with doses which are excessive for a given patient. Increased ventricular extrasystoles, or even ventricular tachycardia or fibrillation may occur. After intravenous administration but seldom after oral therapy, transient high plasma levels of PA may induce hypotension affecting systolic more than diastolic pressures, especially in hypertensive patients. Such high levels may also produce central nervous depression, tremor, and even respiratory depression.

Plasma levels above 10 mcg/mL are increasingly associated with toxic findings, which are seen occasionally in the 10 to 12 mcg/mL range, more often in the 12 to 15 mcg/mL range, and commonly in patients with plasma levels greater than 15 mcg/mL.

Treatment of overdosage or toxic manifestations includes general supportive measures, close observation, monitoring of vital signs and possibly intravenous pressor agents and mechanical cardiorespiratory support. If available, PA and NAPA plasma levels may be helpful in assessing the potential degree of toxicity and response to therapy. Both PA and NAPA are removed from the circulation by hemodialysis ut not peritoneal dialysis. No specific antidote for PA is known.