Monitoring propafenone therapy
Assessing potential toxicity
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
5-Hydroxypropafenone
Rythmol (Propafenone)
Serum Red
Patient Preparation: Specimens should only be collected after patient has been receiving propafenone for at least 3 days. Trough concentrations should be collected just before administration of the next dose.
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions:
1. Draw blood immediately before next scheduled dose.
2. Centrifuge and aliquot serum into plastic vial within 2 hours of collection.
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
0.5 mL
Gross hemolysis | OK |
Gross lipemia | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum Red | Refrigerated (preferred) | 28 days | |
Ambient | 28 days | ||
Frozen | 28 days |
Monitoring propafenone therapy
Assessing potential toxicity
Propafenone (Rythmol) is a class 1C cardiac antiarrhythmic used to treat ventricular arrhythmias (ventricular tachycardia, supraventricular tachycardia, and ventricular premature contractions).
Propafenone undergoes extensive first metabolism (half-life is approximately 2-10 hours). Its clinical efficacy is maintained through the formation of a metabolite (5-hydroxypropafenone) that is more pharmacologically active than the parent drug and has a longer half-life.
Specimens should only be collected after patient has been receiving propafenone orally for at least 3 days. Trough concentrations should be collected just before administration of the next dose. The therapeutic concentration is 0.5 to 2.0 mcg/mL; concentrations less than 0.5 mcg/mL likely indicate inadequate therapy, and propafenone above 2.0 mcg/mL indicates excessive therapy. Adverse side effects are seen in the central nervous system, skin, and gastrointestinal tract.
Trough Value
0.5-2.0 mcg/mL: Therapeutic concentration
>2.0 mcg/mL: Toxic concentration
The therapeutic concentration is 0.5 to 2.0 mcg/mL; concentrations below 0.5 mcg/mL likely indicate inadequate therapy and propafenone above 2.0 mcg/mL indicates excessive therapy.
Specimens that are obtained from gel tubes or anticoagulate collections can cause assay interference.
1. Rifai N, Horwath AR, Wittwer CT: In: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018
2. Josephson ME, Buxton AE, Marchlinski FE: The tachyarrhythmias: tachycardias. In: Wilson JD, Braunwald E, Isselbacher KJ, et al, eds. Harrison's Principles of Internal Medicine. 12th ed. McGraw-Hill Book Company; 1991:915
3. Valdes R Jr, Jortani SA, Gheorghiade M: Standards of laboratory practice: cardiac drug monitoring. National Academy of Clinical Biochemistry. Clin Chem. 1998 May;44(5):1096-1099
4. Joseph SP, Holt DW: Electrophysiological properties of mexiletine assessed with respect to plasma concentrations. Eur J Cardiol. 1980 Feb;11(2):115-121
Monday through Saturday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
80299
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
PFN | Propafenone, S | 6905-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
80295 | Propafenone, S | 6905-4 |