Monitoring duloxetine serum concentration during therapy
Evaluating potential duloxetine toxicity
Evaluating patient compliance
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Ariclaim
Cymbalta (Duloxetine)
Duloxetine (Cymbalta)
Xeristar
Yentreve
Serum Red
Collection Container/Tube: Red top (serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Draw blood immediately before the next scheduled dose (trough).
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 duloxetine serum concentration during therapy
Evaluating potential duloxetine toxicity
Evaluating patient compliance
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 cytochrome P450 (CYP) 1A2 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 collected 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 kidney disease significantly increases exposure to duloxetine due to decreased elimination. Patients with mild-to-moderate kidney dysfunction should be monitored closely; use of duloxetine is not recommended for patients with kidney failure.
Therapeutic ranges are not well-established, but literature suggests that patients receiving duloxetine monotherapy for depression responded well when trough concentrations were 30 to 120 ng/mL. Higher levels may be tolerated by individual patients. The therapeutic relevance of this concentration range to other uses of duloxetine therapy is currently unknown.
Specimens obtained using gel tube or anticoagulant collections cause assay interference.
1. Hiemke C, Bergemann N, Clement HW, et al. Consensus guidelines for therapeutic drug monitoring in neuropsychopharmacology: Update 2017. Pharmacopsychiatry. 2018;51(1-02):9-62
2. Westanmo AD, Gayken J, Haight R. Duloxetine: a balanced and selective norepinephrine- and serotonin-reuptake inhibitor. Am J Health-Syst Pharm. 2005;62(23):2481-2490
3. Waldschmitt C, Vogel F, Pfuhlmann B, Hiemke C. Duloxetine serum concentrations and clinical effects. Data from a therapeutic drug monitoring (TDM) survey. Pharmacopsychiatry. 2009;42(5):189-193
4. Feighner JP, Cohn JB. Double-blind comparative trials of fluoxetine and doxepin in geriatric patients with major depressive disorder. J Clin Psychiatry. 1985;46(3 Pt 2):20-25
5. Kelly MW, Perry PJ, Holstad SG, Garvey MJ. Serum fluoxetine and norfluoxetine concentrations and antidepressant response. Ther Drug Monit. 1989;11:165-170
6. Benfield P, Heel RC, Lewis SP. Fluoxetine: a review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depressive illness. Drugs. 1986;32(6):481-508
7. Wille SM, Cooreman SG, Neels, et al. Relevant issues in the monitoring and toxicology of antidepressants. Crit Rev Clin Lab Sci. 2008;45(1):25-89
Serum samples containing duloxetine are diluted in an aqueous solution containing deuterated internal standard and then injected onto a high-turbulence liquid chromatography system for online extraction. Detection is by tandem mass spectrometry.(Unpublished Mayo method)
Wednesday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
80299
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
DULOX | Duloxetine, S | 46227-5 |
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.
|
---|---|---|
89305 | Duloxetine, S | 46227-5 |