PROCAINAMIDE WITH NAPA

Code
900.3625
Name
PROCAINAMIDE WITH NAPA
Category
None
Department
Send-Out
Start Date
Expiration Date
Synonyms
NAPA; Pronestyl
CPT Codes
80192
Site
SBMF
Reference Test
44863
ATLAS Test Code

Specimen Information

Type

Red, Plain

Volume

1.0 ml

Transport Info

Centrifuge and immediately transfer serum to separate plastic tube
Refrigerated

Fasting Required?
False
Patient Instructions

Reference Range

N-acetylprocainamide (NAPA)
6.0-20.0 µg/mL
Procainamide
4.0-10.0 µg/mL
Critical High Value:

N-acetylprocainamide (NAPA)
Toxic: 35.1 µg/mL or greater
Procainamide
Toxic: 12.1 µg/mL or greater

Methodology

Fluorescence Polarization Immunoassay

Clinical Significance

Used in monitoring levels of N-acetylprocainamide to ensure proper procainamide therapy. Evaluate therapeutic effect or possible toxicity.

N-acetylprocainamide (NAPA), the primary active metabolite of the antiarrhythmic drug procainamide, results from acetylation of procainamide in the liver. NAPA is a less potent antiarrhythmic agent than procainamide and has qualitatively different cardiac actions. IN slow acetylators, approximately 25% of the procainamide dose is converted to NAPA; in rapid acetylators, up to 40% of the dose may be converted to NAPA. Both procainamide and NAPA are chiefly eliminated by the kidneys. NAPA has a slower rate of renal elimination than procainamide and can accumulate rapidly in the presence of renal or circulatory impairment. In that case, NAPA concentrations may reach toxic levels, a circumstance that is exacerbated in rapid acetylators.Because of the variable hepatic conversion and renal elimination of procainamide and NAPA and the attendant possible toxic effects, both compounds should be monitored in patients on chronic procainamide therapy.

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