Venlafaxine Drug Level
Label Mnemonic: VENLA
Epic Lab Code: LAB7476
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Specimen Instructions:
Draw immediately before next scheduled dose. Serum drawn from patients 12 hours after an oral dose is appropriate. It is customary to treat the patient at bedtime with a dose, then draw specimen the following morning prior to next dose.
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
Preferred Minimum: 1 mL serum Absolute Minimum: 0.4 mL serum
Rejection Criteria:
Specimens that are obtained from gel tubes.
Turn Around Time:
3 days upon receipt at reference laboratory
Reference Range:
Venlafaxine + O-desmethylvenlafaxine: 195-400 ng/mL
Interpretive Data:
Most individuals display optimal response to venlafaxine when combined serum levels of venlafaxine and O-desmethylvenlafaxine are between 195 ng/mL to 400 ng/mL. Some individuals may respond well outside of this range, or may display toxicity within the therapeutic range, thus interpretation should include clinical evaluation. Risk of toxicity is increased with combined levels >1,000 ng/mL. Therapeutic ranges are based on specimens drawn at trough (ie, immediately before the next dose).
Comments:
Venlafaxine is a serotonin and norepinephrine reuptake inhibitor (SNRI) approved for treatment of major depression, anxiety and panic disorders, and social phobias. It is also used for bipolar disorder, bulimia, post-traumatic stress, obsessive behavior, and attention- deficit disorder.

Average elimination half-lives are 5 hours for venlafaxine and 10 hours for O-desmethylvenlafaxine, which are much shorter than many other antidepressants. For this reason, extended release formulations are available. Time to peak serum concentration is 2 hours for the regular product and 8 hours for the extended release product. Common toxicities are mild, including drowsiness, dizziness, nausea, and headache.
Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
CPT Code:
80338