Tariquidar-ondansetron Combination in Neuropathic Pain

  • End date
    May 7, 2023
  • participants needed
  • sponsor
    Washington University School of Medicine
Updated on 7 October 2021


Prospective, randomized, double-blind, placebo controlled, cross-over proof of concept study.

To determine the pharmacokinetics and tolerability of co-administration of 5-HT3R antagonist ondansetron with a P-glycoprotein inhibitor tariquidar, in patients with neuropathic pain.


The investigators hypothesize that co-administration of a 5-HT3 receptor antagonist ondansetron (single 16mg dose) with p-glycoprotein inhibitor tariquidar (single 4mg/kg dose) vs placebo in a cross-over prospective randomized study, will:

  1. Be tolerable in patients with neuropathic pain.
  2. Increase the cerebrospinal fluid (CSF) to plasma ratio of ondansetron after intravenous administration, compare to ondansetron alone
  3. Result in a greater reduction in pain intensity than with ondansetron alone.

Condition Post-Surgical Pain, neuropathic pain, Peripheral Neuropathy, Pain (Pediatric), Neuralgia, Pain
Treatment Ondansetron 16 mg with Tariquidar, Ondansetron 16 mg with Placebo
Clinical Study IdentifierNCT04603066
SponsorWashington University School of Medicine
Last Modified on7 October 2021


Yes No Not Sure

Inclusion Criteria

Age 18-65
Documented diagnosis of neuropathic pain due to damage or disease affecting the peripheral nervous system
At least Probable neuropathic pain grading1
Pain duration >3 months
Average pain intensity 4 on 0-10 numerical rating scale (NRS)

Exclusion Criteria

Current pregnancy or lactation
Moderate-severe kidney or liver dysfunction
Active cardiac arrhythmias (non-sinus rhythm), Long QT syndrome, or QTc interval >450msec
Congestive heart failure
Abnormal troponin values at screening visit
Current treatment with MAO inhibitors, mirtazapine, SSRI antidepressants, or SNRI medications duloxetine or venlafaxine
Current treatment with tapentadol, tramadol, or fentanyl
Current treatment with P-glycoprotein substrate drugs with narrow therapeutic window, e.g. digoxin
Current treatment with tricyclic antidepressant medications (e.g. amitriptyline, desipramine, imipramine) at a dose >25mg/day
Ongoing use of any of the following medications with known effects on Pgp function: carbamazepine, phenytoin, phenobarbital, cyclosporine, clarithromycin, erythromycin, ritonavir, verapamil, rifampicin, St. John's wort
Current treatment with QT-prolonging drugs, and drugs known to have a significant interaction with ondansetron or other P-glycoprotein substrates (see section 2.3.3.)
Current treatment with anticoagulant drugs
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