Huntington DiseasePhase 3NCT03854019

Evaluating the Efficacy of Dextromethorphan/Quinidine in Treating Irritability in Huntington's Disease

A Phase 3 study testing Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg) in people with Huntington Disease and Irritability, run by The University of Texas Health Science Center, Houston at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The purpose of this study is to assess efficacy and safety of dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg) in patients with irritability due to Huntington's disease. Read more about this study

Who is it for?: Ages 18 to 75 yearsHealthy volunteers can take part
Conditions the study is for: Huntington Disease, Irritability
What is being tested?: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 20 participants
Where: 1 siteUnited States
Study dates: 5 Aug 2019to 11 Nov 2022
Phase: Phase 3
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 75 years
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

Verified HD mutation carriers;
Irritable as diagnosed by the Irritability Scale with a score > 14;
Stable concomitant medication (no change of medication during last 30 days prior to inclusion);
Written informed consent by prospective study participant before conduct of any trial-related procedure. Participant must be able to make an informed decision of whether or not to participate in the study.

Who cannot join

Hypersensitivity to dextromethorphan (e.g., rash, hives), quinine, mefloquine, quinidine, or dextromethorphan/quinidine with a history of thrombocytopenia, hepatitis, bone marrow depression or lupus-like syndrome induced by these drugs;
Pregnant or nursing women;
Active suicidality based on the answer "yes" in questions 4 and 5 of the Columbia-Suicide Severity Rating Scale (baseline version);
Woman of childbearing potential, not using highly effective methods of contraception such as oral, topical or injected contraception, IUD, contraceptive vaginal ring, or double barrier method such as diaphragm and condom with spermicide) or not surgically sterile (via hysterectomy, ovarectomy or bilateral tubal ligation) or not at least one year post-menopausal;
Male not using an acceptable barrier method for contraception;
Presence of any medically not controllable disease (e.g. uncontrolled arterial hypertension or diabetes mellitus);

Show all 22Show fewer

Clinically significant renal (calculated creatinine clearance < 30 ml/min) or hepatic dysfunction;
Patients with pre-existing hepatic disease;
Individuals with a history or complete heart block, QTc prolongation or tornadoes de pointes, or at high risk of complete AV block;
Family history of congenital QT prolongation;
History of unexplained syncope within the past year;
Use of drugs containing quinidine, quinine, or mefloquine;
Individuals currently taking strong CYP3A4 inhibitors or tetrabenazine;
Use of certain antidepressants--amitriptyline, clomipramine, desipramine, fluoxetine, paroxetine, sertraline, venlafaxine;
Use of certain heart rhythm medications--amiodarone, flecainide, procainamide, propafenone;
Use of certain medicines to treat psychiatric disorders--chlorpromazine, haloperidol, perphenazine, pimozide, quetiapine, risperidone, thioridazine.
Use of tamoxifen;
Presence or history of seizures or diagnosed epilepsy;
Severe cognitive disorders defined as a score < 18 on the MOCA;
Clinically relevant abnormal findings in the ECG, the vitals, in the physical examination or laboratory values at screening that could interfere with the objectives of the study or the safety of the subject as judged by the investigator;
Participation in another investigative drug trial within 2 months;
Subjects who are unlikely to be compliant and attend scheduled clinic visits as required as determined by the Investigator.

Trial locations and contacts

1 site in 1 country.

United States1 site

The University of Texas Health Science Center at Houston
Houston, Texas, 77030

Other trials in United States

About this study

The purpose of this study is to assess efficacy and safety of dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg) in patients with irritability due to Huntington's disease.

Conditions: Huntington Disease, Irritability
Being tested: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), Placebo
Keywords: Irritability
Medical subject headings: Huntington Disease

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)Drug
Also called Nuedexta
DM/Q 20mg/10mg one capsule once daily for 1 week, followed by DM/Q 20mg /10 mg twice daily for subsequent 4 weeks, and finally DM/Q 20mg/10mg once daily for 7days.
PlaceboDrug
Placebo once daily for 1 week, followed by placebo twice daily for subsequent 4 weeks, and finally placebo once daily for 7days.

Study groups in NCT03854019
Study group	Role	What they receive
Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), then Placebo	Experimental	Dextromethorphan/quinidine (DM/Q) 20mg/10mg one capsule once daily for 1 week, followed by DM/Q 20mg /10 mg twice daily for subsequent 4 weeks, and finally DM/Q 20mg/10mg once daily for 7days. Receives: Drug: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg); Drug: Placebo
Placebo, then Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)	Placebo comparator	Placebo one capsule once daily for 1 week, followed by placebo twice daily for subsequent 4 weeks, and finally placebo once daily for 7days. Receives: Drug: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg); Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Irritability as Assessed by The Irritability Scale.
The Irritability Scale total score ranges from 0 to 42, with higher scores indicating greater irritability.
Measured: Baseline
Irritability as Assessed by The Irritability Scale
The Irritability Scale total score ranges from 0 to 42, with higher scores indicating greater irritability.
Measured: 4 weeks

Secondary outcomes (25)

Behavioral Symptoms, as Assessed by the Hospital Anxiety and Depression Scale (HADS).
The HADS is a self-report, 14-item scale (7 items relate to anxiety and 7 relate to depression) used to determine the levels of anxiety and depression that a person is experiencing. The total score ranges from 0 to 42 (21 per subscale), with higher scores signifying worse symptoms.
Measured: Baseline
Behavioral Symptoms, as Assessed by the Hospital Anxiety and Depression Scale (HADS).
The HADS is a self-report, 14-item scale (7 items relate to anxiety and 7 relate to depression) used to determine the levels of anxiety and depression that a person is experiencing. The total score ranges from 0 to 42 (21 per subscale), with higher scores signifying worse symptoms.
Measured: 4 weeks
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Severity Score.
The NPI-Q is a 12-domain informant-based interview that assesses neuropsychiatric symptoms over the previous month.The total NPI-Q severity score ranges from 0 to 36, with higher scores indicate greater symptoms severity.
Measured: Baseline
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Severity Score.
The NPI-Q is a 12-domain informant-based interview that assesses neuropsychiatric symptoms over the previous month.The total NPI-Q severity score ranges from 0 to 36, with higher scores indicate greater symptoms severity.
Measured: 4 weeks
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Caregiver Distress.
Caregiver distress associated with the symptom is rated on an anchored 0- to 5-point scale, which total sum ranges from 0 to 60. Higher scores indicate greater caregiver distress related to patient's neuropsychiatric symptoms.
Measured: Baseline
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Caregiver Distress.
Caregiver distress associated with the symptom is rated on an anchored 0- to 5-point scale, which total sum ranges from 0 to 60. Higher scores indicate greater caregiver distress related to patient's neuropsychiatric symptoms.
Measured: 4 weeks
Behavioral Symptoms, as Assessed by the Problem Behaviors Assessment - Short Version (PBA-s). - Irritability/Aggression Subscale
The PBA-s is a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. The PBA-s is an 11-item scale rating the frequency and severity of symptoms. The total score for irritability/aggression subscale ranges from 0 to 32, with higher scores indicating greater behavioral symptoms severity.
Measured: Baseline
Behavioral Symptoms, as Assessed by the Problem Behaviors Assessment - Short Version (PBA-s) - Irritability/Aggression Subscale
The PBA-s is a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. The PBA-s is an 11-item scale rating the frequency and severity of symptoms. The total score for irritability/aggression subscale ranges from 0 to 32, with higher scores indicating greater behavioral symptoms severity.
Measured: 4 weeks
Motor Symptoms, as Assessed by the Total Motor Score (TMS) From the UHDRS.
The TMS comprises the motor section of the UHDRS, a 31-item subscale that comprehensively evaluates motor aspects of HD. The overall 31 items are each rated from grade 0 (not affected) to grade 4 (most severely affected), resulting in a range of 0-124 points.
Measured: Baseline
Motor Symptoms, as Assessed by the Total Motor Score (TMS) From the UHDRS.
The TMS comprises the motor section of the UHDRS, a 31-item subscale that comprehensively evaluates motor aspects of HD. The overall 31 items are each rated from grade 0 (not affected) to grade 4 (most severely affected), resulting in a range of 0-124 points.
Measured: 4 weeks
Motor Symptoms, as Assessed by the Total Maximal Chorea (TMC).
The TMC comprises 7 of the 31 items in the TMS, which are related to chorea symptoms. The total TMC score ranges from 0 to 28, with higher scores indicating greater chorea severity.
Measured: Baseline
Motor Symptoms, as Assessed by the Total Maximal Chorea (TMC).
The TMC comprises 7 of the 31 items in the TMS, which are related to chorea symptoms. The total TMC score ranges from 0 to 28, with higher scores indicating greater chorea severity.
Measured: 4 weeks
Functional Independence, as Assessed by the UHDRS Total Functional Capacity Scale (TFC).
The TFC lists five stages of Huntington's Disease and five levels of function in the domains of workplace, finances, domestic chores, activities of daily living and requirements for unskilled or skilled care. The total TFC score ranges from 0 to 13, with higher scores signifying better functioning.
Measured: Baseline
Functional Independence, as Assessed by the UHDRS Total Functional Capacity Scale (TFC).
The TFC lists five stages of Huntington's Disease and five levels of function in the domains of workplace, finances, domestic chores, activities of daily living and requirements for unskilled or skilled care. The total TFC score ranges from 0 to 13, with higher scores signifying better functioning.
Measured: 4 weeks
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Ideation.
The C-SSRS is a suicidal ideation and behavior rating scale with yes/no responses. The first part (Items 1-5) rates an individual's degree of suicidal ideation on a 0-5 scale, ranging from "wish to be dead" to "active suicidal ideation with specific plan and intent and behaviors". The C-SSRS outcomes are categories and have binary responses (yes/no). Suicidal ideation is considered when the patient responds a "yes" answer at any time during treatment to any one of the five suicidal ideation questions (Categories 1-5) on the C-SSRS. The sum of the 5 intensity item scores create a total score (range 0 to 25) to represent the intensity rating (higher scores indicate more severe suicidal ideation).
Measured: Baseline
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Ideation
The C-SSRS is a suicidal ideation and behavior rating scale with yes/no responses. The first part (Items 1-5) rates an individual's degree of suicidal ideation on a 0-5 scale, ranging from "wish to be dead" to "active suicidal ideation with specific plan and intent and behaviors". The C-SSRS outcomes are categories and have binary responses (yes/no). Suicidal ideation is considered when the patient responds a "yes" answer at any time during treatment to any one of the five suicidal ideation questions (Categories 1-5) on the C-SSRS. The sum of the 5 intensity item scores create a total score (range 0 to 25) to represent the intensity rating (higher scores indicate more severe suicidal ideation).
Measured: 4 weeks
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Behavior.
The questions 6-10 of the C-SSRS are related to suicidal behavior, and the outcome is a simple yes/no response. Suicidal behavior occurs if the patient answers a "yes" at any time during treatment to any one of the five suicidal behavior questions (Categories 6-10) on the C-SSRS.
Measured: Baseline
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Behavior.
The questions 6-10 of the C-SSRS are related to suicidal behavior, and the outcome is a simple yes/no response. Suicidal behavior occurs if the patient answers a "yes" at any time during treatment to any one of the five suicidal behavior questions (Categories 6-10) on the C-SSRS.
Measured: 4 Weeks
Cognitive Symptoms, as Assessed by the The Montreal Cognitive Assessment (MoCA).
The MoCA is a rapid screening instrument for mild cognitive dysfunction. It assesses different cognitive domains with a total possible score of 0 to 30 points; a score of 26 or above is considered normal for the general population.
Measured: Baseline
Cognitive Symptoms, as Assessed by the The Montreal Cognitive Assessment (MoCA).
The MoCA is a rapid screening instrument for mild cognitive dysfunction. It assesses different cognitive domains with a total possible score of 0 to 30 points; a score of 26 or above is considered normal for the general population.
Measured: 4 weeks
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Severity Scale (CGI-S).
The CGI is a stand-alone assessment of the clinician's view of the patient's global functioning prior to and after initiating a study medication.
Measured: Baseline
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Severity Scale (CGI-S).
The CGI is a stand-alone assessment of the clinician's view of the patient's global functioning prior to and after initiating a study medication. The CGI is a 3-item observer-rated scale that measures illness severity (CGI-S), global improvement or change (CGI-I) and therapeutic response. The scale ranges from 1-7, with higher scores indicating worse outcomes.
Measured: 4 weeks
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Improvement Scale (CGI-I).
The CGI is a stand-alone assessment of the clinician's view of the patient's global functioning prior to and after initiating a study medication.
Measured: 4 weeks
Cognitive Symptoms, as Assessed by the Unified Huntington's Disease Rating Scale (UHDRS) - Cognitive Domain.
The UHDRS - cognitive function assessment a phonetic verbal fluency test, the Symbol Digit Modalities Test, and the Stroop Interference Test. These tests do not have a predefined score range, but higher scores indicate better cognitive performance.
Measured: Baseline
Cognitive Symptoms, as Assessed by the Unified Huntington's Disease Rating Scale (UHDRS) - Cognitive Domain.
The UHDRS - cognitive function assessment a phonetic verbal fluency test, the Symbol Digit Modalities Test, and the Stroop Interference Test. These tests do not have a predefined score range, but higher scores indicate better cognitive performance.
Measured: 4 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

5 Aug 201911 Nov 2022

First posted26 Feb 2019
Study start5 Aug 2019
Primary completion11 Nov 2022
Study completion11 Nov 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Huntington DiseaseStudies of the same condition, open and under way.
More trials run by The University of Texas Health Science Center, HoustonThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 3
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Crossover
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 20 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT03854019
Sponsor's protocol ID: HSC-MS-18-1049
Status last verified: Jan 2024
First submitted: 22 Feb 2019
Last updated: 5 Jan 2024
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No

Publications

Zadegan SA, Calderon O, Karagas N, Patino J, Dongarwar D, Duncan B, Teixeira AL, Rocha NP, Furr Stimming E. Assessing the efficacy of dextromethorphan/quinidine in treating irritability in Huntington's disease. J Huntingtons Dis. 2026 Aug;15(3):332-341. doi: 10.1177/18796397251411112. Epub 2026 Jan 7.
PubMed 41499296

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Huntington Disease trials

Study at a glance

From the registry record, last updated by the sponsor on 5 Jan 2024. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Evaluating the Efficacy of Dextromethorphan/Quinidine in Treating Irritability in Huntington's Disease
ClinicalTrials.gov ID: NCT03854019
Acronym / sponsor ID: HSC-MS-18-1049
Conditions: Huntington Disease, Irritability
Keywords: Irritability
Phase: Phase 3
Study type: Interventional
Recruitment status: Completed
Enrolment: 20 participants (actual)
Lead sponsor: The University of Texas Health Science Center, HoustonUniversity, hospital or other
Collaborators: Cures Within Reach
Study start: 5 Aug 2019 (actual)
Primary completion: 11 Nov 2022 (actual)
Study completion: 11 Nov 2022 (actual)
First posted: 26 Feb 2019 (actual)
Results: Posted 5 Jan 2024

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The purpose of this study is to assess efficacy and safety of dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg) in patients with irritability due to Huntington's disease.

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Crossover
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 2

Arm	Type	Receives
Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), then Placebo	Experimental	Drug: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), Drug: PlaceboDextromethorphan/quinidine (DM/Q) 20mg/10mg one capsule once daily for 1 week, followed by DM/Q 20mg /10 mg twice daily for subsequent 4 weeks, and finally DM/Q 20mg/10mg once daily for 7days.
Placebo, then Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)	Placebo comparator	Drug: Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), Drug: PlaceboPlacebo one capsule once daily for 1 week, followed by placebo twice daily for subsequent 4 weeks, and finally placebo once daily for 7days.

Who may qualify

Ages: 18 to 75 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (4 listed)

Verified HD mutation carriers;
Irritable as diagnosed by the Irritability Scale with a score > 14;
Stable concomitant medication (no change of medication during last 30 days prior to inclusion);
Written informed consent by prospective study participant before conduct of any trial-related procedure. Participant must be able to make an informed decision of whether or not to participate in the study.

Key exclusion criteria (22 listed)

Hypersensitivity to dextromethorphan (e.g., rash, hives), quinine, mefloquine, quinidine, or dextromethorphan/quinidine with a history of thrombocytopenia, hepatitis, bone marrow depression or lupus-like syndrome induced by these drugs;
Pregnant or nursing women;
Active suicidality based on the answer "yes" in questions 4 and 5 of the Columbia-Suicide Severity Rating Scale (baseline version);
Woman of childbearing potential, not using highly effective methods of contraception such as oral, topical or injected contraception, IUD, contraceptive vaginal ring, or double barrier method such as diaphragm and condom with spermicide) or not surgically sterile (via hysterectomy, ovarectomy or bilateral tubal ligation) or not at least one year post-menopausal;
Male not using an acceptable barrier method for contraception;

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)Also: NuedextaDM/Q 20mg/10mg one capsule once daily for 1 week, followed by DM/Q 20mg /10 mg twice daily for subsequent 4 weeks, and finally DM/Q 20mg/10mg once daily for 7days.	Drug	Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), then Placebo, Placebo, then Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)
PlaceboPlacebo once daily for 1 week, followed by placebo twice daily for subsequent 4 weeks, and finally placebo once daily for 7days.	Drug	Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg), then Placebo, Placebo, then Dextromethorphan/quinidine 20mg/10mg (DM/Q 20mg/10mg)

Primary outcome

Irritability as Assessed by The Irritability Scale.
Time frame: Baseline
The Irritability Scale total score ranges from 0 to 42, with higher scores indicating greater irritability.
Irritability as Assessed by The Irritability Scale
Time frame: 4 weeks
The Irritability Scale total score ranges from 0 to 42, with higher scores indicating greater irritability.

25 secondary outcomes

Behavioral Symptoms, as Assessed by the Hospital Anxiety and Depression Scale (HADS).
Time frame: Baseline
Behavioral Symptoms, as Assessed by the Hospital Anxiety and Depression Scale (HADS).
Time frame: 4 weeks
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Severity Score.
Time frame: Baseline
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Severity Score.
Time frame: 4 weeks
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Caregiver Distress.
Time frame: Baseline
Behavioral Symptoms, as Assessed by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) - Caregiver Distress.
Time frame: 4 weeks
Behavioral Symptoms, as Assessed by the Problem Behaviors Assessment - Short Version (PBA-s). - Irritability/Aggression Subscale
Time frame: Baseline
Behavioral Symptoms, as Assessed by the Problem Behaviors Assessment - Short Version (PBA-s) - Irritability/Aggression Subscale
Time frame: 4 weeks
Motor Symptoms, as Assessed by the Total Motor Score (TMS) From the UHDRS.
Time frame: Baseline
Motor Symptoms, as Assessed by the Total Motor Score (TMS) From the UHDRS.
Time frame: 4 weeks
Motor Symptoms, as Assessed by the Total Maximal Chorea (TMC).
Time frame: Baseline
Motor Symptoms, as Assessed by the Total Maximal Chorea (TMC).
Time frame: 4 weeks
Functional Independence, as Assessed by the UHDRS Total Functional Capacity Scale (TFC).
Time frame: Baseline
Functional Independence, as Assessed by the UHDRS Total Functional Capacity Scale (TFC).
Time frame: 4 weeks
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Ideation.
Time frame: Baseline
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Ideation
Time frame: 4 weeks
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Behavior.
Time frame: Baseline
Number of Participants With Behavioral Suicidal Events, as Assessed by the Columbia-Suicide Severity Rating Scale (C-SSRS) - Suicidal Behavior.
Time frame: 4 Weeks
Cognitive Symptoms, as Assessed by the The Montreal Cognitive Assessment (MoCA).
Time frame: Baseline
Cognitive Symptoms, as Assessed by the The Montreal Cognitive Assessment (MoCA).
Time frame: 4 weeks
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Severity Scale (CGI-S).
Time frame: Baseline
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Severity Scale (CGI-S).
Time frame: 4 weeks
Patient Progress and Treatment Response Over Time, as Assessed by the Clinical Global Impressions Improvement Scale (CGI-I).
Time frame: 4 weeks
Cognitive Symptoms, as Assessed by the Unified Huntington's Disease Rating Scale (UHDRS) - Cognitive Domain.
Time frame: Baseline
Cognitive Symptoms, as Assessed by the Unified Huntington's Disease Rating Scale (UHDRS) - Cognitive Domain.
Time frame: 4 weeks

Results and safety

Results posted to the registry on 5 Jan 2024, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Dextromethorphan/Quinidine 20mg/10mg (DM/Q 20mg/10mg), Then Placebo	10	9
Placebo, Then Dextromethorphan/Quinidine 20mg/10mg (DM/Q 20mg/10mg)	10	9

Primary outcome: Irritability as Assessed by The Irritability Scale.

Time frame: Baseline. Mean (Standard Deviation). Unit: score on a scale

Measure	All Study Participants Pre-Randomization n = 18
Value	27.5 (5.8)

Primary outcome: Irritability as Assessed by The Irritability Scale

Time frame: 4 weeks. Mean (Standard Deviation). Unit: score on a scale

Measure	Dextromethorphan/Quinidine 20mg/10mg (DM/Q 20mg/10mg) n = 18	Placebo n = 18
Value	18.7 (10.1)	19.9 (9.4)

25 secondary outcomes are reported in the full results.

Adverse events

Time frame: 13 weeks. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Dextromethorphan/Quinidine 20mg/10mg (DM/Q 20mg/10mg)	0 of 20 (0%)	10 of 20 (50%)	0 of 20
Placebo	1 of 20 (5%)	5 of 20 (25%)	0 of 20

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 5 Jan 2024.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 41499296Zadegan SA, Calderon O, Karagas N, Patino J, Dongarwar D, Duncan B, Teixeira AL, Rocha NP, Furr Stimming E. Assessing the efficacy of dextromethorphan/quinidine in treating irritability in Huntington's disease. J Huntingtons Dis. 2026 Aug;15(3):332-341. doi: 10.1177/18796397251411112. Epub 2026 Jan 7.
Individual participant dataSharing planned: No

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Erin L Furr Stimming, MD principal investigator

The University of Texas Health Science Center, Houston

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 22 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 5 Jan 2024. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 5 Jan 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Irritability as Assessed by The Irritability Scale. (time frame: Baseline). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03854019, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Jan 2024.