Amiodarone - plasma or serum

Last updated: Wednesday, 07, April, 2004

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Item Process
Specimen

5 mL blood in lithium heparin or plain tube. Gel tubes should not be used.

The specimen should be collected <4 hours after the last dose.

Method

HPLC. Some laboratories measure an active metabolite, desethylamiodarone.

Reference Interval

1.5-4.0 μmol/L (1.0-2.5 mg/L).

Application

Monitoring amiodarone therapy.

Interpretation

The drug has an elimination half-life of approximately 40 days, so reassessment after a change in dose should not be done for approximately 3 months.

Toxic effects may not become evident for some months after therapy is commenced (or altered) and can occur with levels within the therapeutic interval.

TSH should be measured intermittently in all patients as the drug can cause hypothyroidism or hyperthyroidism.

Reference

Siddoway LA. Am Fam Physician 2003; 68(11): 2189-2196.