Sign in →

Test ID DULOX Duloxetine, Serum

Useful For

Monitoring serum concentration during therapy 

 

Evaluating potential toxicity 

 

Evaluating patient compliance

Method Name

High-Turbulence Liquid Chromatography Mass Spectrometry (HTLC-MS/MS)

Reporting Name

Duloxetine, S

Specimen Type

Serum Red

Container/Tube: Red top

Specimen Volume: 1 mL

Collection Instructions: 

1. As is the case for most therapeutic drugs, trough specimens are preferred for monitoring duloxetine concentrations and should be drawn immediately before the next scheduled dose.

2. Spin down within 2 hours of draw.

Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  24 hours

Clinical Information

Duloxetine is an antidepressant of the serotonin-norepinephrine reuptake inhibitor class. It is effective in treating symptoms of depression, including physical pain associated with depression; other uses include therapy of neuropathic pain, fibromyalgia, and urinary stress incontinence. Duloxetine also inhibits serotonin uptake in human platelets, and may be associated with potentiation of bleeding.

 

Duloxetine undergoes extensive hepatic biotransformation to numerous inactive metabolites. The drug is metabolized by CYP1A2 and CYP2D6, with moderate potential for drug interactions (duloxetine is both a substrate and a moderate inhibitor of CYP2D6). The mean elimination half-life is 12.5 hours with steady-state concentrations occurring in about 3 days. Specimens for therapeutic monitoring should be drawn immediately before the next scheduled dose (ie, trough).

 

Duloxetine is not recommended for patients with hepatic impairment, substantial alcohol use, or chronic liver disease. Use in patients with renal disease significantly increases exposure to duloxetine due to decreased elimination. Patients with mild-to-moderate renal dysfunction should be monitored closely; use of duloxetine is not recommended in end-stage renal disease.

Reference Values

60-120 ng/mL

Cautions

This test cannot be performed on whole blood. Serum must be separated from cells within 2 hours of draw. Specimens that are obtained from gel tubes are not acceptable.

Day(s) Performed

Wednesday; 12 a.m.

Report Available

1 day/2 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information

80332

G0480 (if appropriate)

NY State Approved

Yes