Study to Examine the Effect of Gastric Bypass Surgery on Venlafaxine ER Blood Levels

  • Study type:

    Interventional What is this?

    Describes the nature of a clinical study. Types include:

    • Observational study — observes people and measures outcomes without affecting results.
    • Interventional study (clinical trial) — studies new tests, treatments, drugs, surgical procedures or devices.
    • Medical records research — uses historical information collected from medical records of large groups of people to study how diseases progress and which treatments and surgeries work best.
  • Study phase:

    0 What is this?

    During the early phases (phases 1 and 2), researchers assess safety, side effects, optimal dosages and risks/benefits. In the later phase (phase 3), researchers study whether the treatment works better than the current standard therapy. They also compare the safety of the new treatment with that of current treatments. Phase 3 trials include large numbers of people to make sure that the result is valid. There are also less common very early (phase 0) and later (phase 4) phases. Phase 0 trials are small trials that help researchers decide if a new agent should be tested in a phase 1 trial. Phase 4 trials look at long-term safety and effectiveness, after a new treatment has been approved and is on the market.

Study IDs

  • Site IRB:

    • Rochester, Minnesota: 12-005860
  • NCT ID:

  • Sponsor Protocol Number:


About this study

The purpose of the study is to determine whether a significant and predictable change in bioavailability of extended-release venlafaxine occurs following Roux-en-Y gastric bypass.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. If you need assistance understanding the eligibility criteria, please contact the study team.

See eligibility criteria

Inclusion criteria:

  • Approved to undergo Roux-en-Y gastric bypass surgery (cost of surgery is NOT included in the study)

Exclusion criteria:

  • Pregnant
  • Allergy to venlafaxine or desvenlafaxine
  • Psychiatric hospitalization within the prior 12 months
  • Active professional treatment for recent substance abuse within 12 months of abstinence
  • Ongoing psychologic issues, such as personality disorders, difficulties as a trauma survivor, or difficulties with depression unless a stable, documented course of treatment by a licensed mental health professional is available
  • Current use of any of the following medications/supplements: 5-hydroxytryptophan, almotriptan, amitriptyline, amoxapine, amoxicillin-clavulanate, amphetamine-dextroamphetamine, atazanavir, bupropion, cinacalcet, citalopram, clarithromycin, clomipramine, desipramine, desvenlafaxine, dextroamphetamine, dextromethorphan, doxepin, duloxetine, eletriptan, entacapone, escitalopram, fluoxetine, fluvoxamine, frovatriptan, haloperidol, imipramine, isocarboxazid, itraconazole, jujube seed extract, linezolid, maprotiline, methylene blue, metoclopramide, metoprolol, milnacipran, mirtazapine, naratriptan, nefazodone, nelfinavir, nortriptyline, paroxetine, phenelzine, procarbazine, protriptyline, quinidine, rasagiline, ritonavir, rizatriptan, saquinavir, selegiline, sertraline, St. John's wort, sumatriptan, tapentadol, terbinafine, toremifene, tramadol, tranylcypromine, trazodone, trifluoperazine, trimipramine, tryptophan, L-tryptophan, venlafaxine, vilazodone, zolmitriptan

Participating Mayo Clinic locations

Study statuses change often. Please contact us for help.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Carrie Krieger, Pharm.D., R.Ph.

Closed for enrollment

Heather Binner