Venlafaxine Drug Level
Label Mnemonic: | VENLA |
Epic code: | LAB7476 |
Downtime form: | A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery |
Commercial Mailout Laboratory
6240-8 RCP
356-8593
6240-8 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.
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