Study of Dextromethorphan in OCD and Related Disorders

Stanford University

Status and phase: Enrolling; Phase 2

Conditions: Obsessive-Compulsive Disorder; Somatic Symptom Disorder; Illness Anxiety Disorder; Body Dysmorphic Disorders

Treatments: Drug: Dextromethorphan; Drug: Fluoxetine

Study type: Interventional

Funder types: Other

Identifiers

NCT04899687

60569

Details and patient eligibility

About

The purpose of the study is to assess the tolerability and efficacy of dextromethorphan in combination with fluoxetine for symptom relief in OCD and related disorders.

Full description

Obsessive compulsive disorder (OCD) and the related disorders body dysmorphic disorder (BDD), somatic symptom disorder (SSD) and illness anxiety disorder (IAD) are psychiatric conditions characterized by recurrent, intrusive thoughts, feelings or images (obsessions or preoccupations) and repetitive or ritualized behaviors or avoidance performed to relieve obsession or preoccupation-related anxiety. They are a significant cause of mental health-related disability, and are inadequately served by available treatments.

This study tests whether an over-the-counter cough suppressant medicine, dextromethorphan, may offer symptom relief when combined with a low dose of fluoxetine, a standard prescription treatment for OCD and related disorders.

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Diagnosis of obsessive-compulsive disorder (OCD), body dysmorphic disorder (BDD), illness anxiety disorder (IAD) or somatic symptom disorder (SSD)
• Living within California
• Capacity to provide informed consent

Exclusion criteria

• Current bipolar disorder or psychotic disorder
• Active moderate or severe substance use disorder, lifetime severe substance use disorder
• Pregnant or nursing women
• Use of prescribed psychotropic medications other than fluoxetine for 2 weeks prior to study start
• Having commenced OCD-targeted exposure and response-prevention (ExRP) psychotherapy within 2 months of study start

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Single Blind

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60 participants in 2 patient groups

Group A: fluoxetine then fluoxetine plus dextromethorphan

Experimental group

Description:

Group A participants will take fluoxetine 20mg (or prior dose) daily for 4 weeks, and will then continue fluoxetine while adding over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks.

Treatment:

Drug: Fluoxetine

Drug: Dextromethorphan

Group B: fluoxetine plus dextromethorphan then fluoxetine

Experimental group

Description:

Group B participants will take fluoxetine 20mg (or prior dose) daily together with over the counter dextromethorphan, with doses increasing weekly as tolerated, for 4 weeks, and then will stop dextromethorphan, continuing fluoxetine alone for 4 weeks.

Treatment:

Drug: Fluoxetine

Drug: Dextromethorphan