Recruiting
Phase 2
Phase 3

5-HTP

Sponsor:

University of Alberta

Code:

NCT04520178

Conditions

Spinal Cord Injuries

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Interventions

5-Hydroxytryptophan 100 MG

5-Hydroxytryptophan

Carbidopa

Placebo

Study Details

Brief summary:

This study will assess how the serotonin precursor, 5-HTP, alter nervous system excitability and motor function in individuals with spinal cord injuries of differing chronicity and severity. Participants will visit the lab on 4 separate occasions where they will be administered four different drugs in a randomized, double-blinded, placebo-controlled crossover design.

Conditions

Spinal Cord Injuries

Study ID

NCT04520178

Start date

Jul 1, 2020

Status verified date

Aug, 2025

Completion date

Dec 30, 2026

Anticipated

Primary completion date

Jun 30, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • participants must have suffered trauma to the spinal cord at least six months ago or longer

Exclusion Criteria:

  • individuals with damage to the nervous system other than to the spinal cord
  • pregnant and/or breastfeeding women
  • alcoholic participants
  • history of seizure/epilepsy
  • history of suicidal thoughts or behaviors
  • known or suspected allergy to the medication ingredients
  • cardiovascular disease including history of heart attack or heart rhythm irregularities
  • coronary artery disease
  • reduced liver function or disease
  • reduced kidney function or disease
  • lung disease
  • comatose or depressed states due to CNS depressants
  • endocrine dysfunction
  • blood dyscrasias or blood related disease
  • bone marrow depression
  • hypocalcemia
  • history of stomach ulcers
  • wide angle glaucoma
  • phenylketonuria
  • history of tumors
  • uncontrolled heart problems
  • unstable psychiatric or mental disorder

Participants taking:

  • monoamine oxidase inhibitor therapy
  • serotonergic antidepressants
  • tricyclic antidepressants
  • any type of serotonergic agonist
  • dopamine D2 receptor antagonists
  • amphetamine
  • CNS depressants
  • levodopa
  • lithium
  • anti-hypertensive drugs
  • iron salts
  • metoclopramide
  • phenothiazine medication

Study Design

Enrollment

30 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

active comparator: Low-dose 5HTP

50mg 5-HTP in combination with 50mg carbidopa

active comparator: High-dose 5HTP

100mg 5-HTP in combination with 50mg carbidopa

sham comparator: Carbidopa

50mg carbidopa only

placebo comparator: Placebo

Placebo comparator

Interventions

5-Hydroxytryptophan 100 MG

100mg combined with 50mg carbidopa

5-Hydroxytryptophan

50mg combined with 50mg carbidopa

Carbidopa

50mg

Placebo

Placebo

Primary outcome measure

  • Change in motoneuron excitability [ Time Frame: Pre drug-intake, 30minutes, 60minutes, 90minutes and 120minutes post drug-intake ]
  • Change in spinal excitability [ Time Frame: Pre drug-intake, 30minutes, 60minutes, 90minutes and 120minutes post drug-intake ]
  • Change in flexor reflex/spasms [ Time Frame: Pre drug-intake, 30minutes, 60minutes, 90minutes and 120minutes post drug-intake ]
  • Change in functional movement performance [ Time Frame: Pre drug-intake, 120-150minutes post drug-intake ]

Central Contacts and Locations

Central contacts

Jessica D'Amico, PhD

780-735-7917damico1@ualberta.ca

Locations

University of Alberta

Recruiting

Edmonton, Alberta, Canada, T6G-2E1

Contacts

Jessica D'Amico, PhD

780-735-7917damico1@ualberta.ca

Principal Investigator:

Monica A Gorassini, PhD

More Information

Sponsor

University of Alberta

Last update posted

Aug 27, 2025

Last verified

Aug, 2025

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Alberta on 2025-08-27.