Naltrexone for Impulse Control Disorders in Parkinson's Disease

Phase 4

Completed

Conditions: Parkinson Disease
Impulse Control Disorder

Interventions: Drug: Placebo
Drug: Naltrexone

Registration Number: NCT01052831

Lead Sponsor: University of Pennsylvania

Brief Summary: This study will evaluate the effectiveness of naltrexone in reducing ICD symptoms in Parkinson's disease patients taking a dopamine agonist.

Detailed Description: Impulse control disorders (ICDs), including compulsive gambling, sexual behavior, buying, and eating, are increasingly recognized as a significant clinical problem in Parkinson's disease (PD), occurring in up to 15% of patients. Dopamine agonist (DA) treatment is thought to be the primary risk factor for the development of ICDs in PD. ICDs often lead to significant impairments in psychosocial functioning, interpersonal relationships, and quality of life. The management of ICDs in the context of PD can be complex. Patients may be reluctant to discontinue DA treatment due to the motor benefits derived from treatment, so patients often have chronic symptoms. Thus, additional treatment approaches are needed.

A medication shown to be efficacious for the treatment of ICDs with minimal impact on parkinsonism would allow many ICD patients to continue on full-dose DA treatment. Naltrexone, a long-acting opioid receptor antagonist, helps in the treatment of alcohol and opioid dependence. In addition, placebo-controlled studies have demonstrated that it helps in the treatment of pathological gambling in the general population. Opioids regulate dopamine pathways in areas of the brain linked with impulse control disorders, and opioid antagonists block opioid receptors in these regions. In this study, 48 PD patients with an ICD will be treated either with naltrexone (50-100 mg/day) or placebo for a period of 8 weeks. The study will assess if naltrexone improves ICD symptoms in PD and is well tolerated. To our knowledge, the proposed study is the first controlled trial of an agent to treat ICDs in PD.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 50

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Participants received the placebo treatment which looked identical to active study medication.
Naltrexone	Naltrexone	For the first four weeks of the study, participants were administered naltrexone at 50mg per day. Participants not in response at week 4 were increased to 100mg per day for the remaining four weeks of the study.

Primary Outcome Measures

Name	Time	Method
Percentage of Participants Assessed as Very Much Improved or Much Improved Based on the Clinical Global Impression-Improvement (CGI-I) Scale	The CGI-I was administered at Visit 2 (week 2, two weeks after baseline) and Visit 5 (week 8, termination visit 8 weeks after baseline).	The Clinical Global Impression-Improvement scale rates total improvement on a 7 point scale: 1. = Very much improved 2. = Much improved 3. = Minimally improved 4. = No change 5. = Minimally worse 6. = Much worse 7. = Very much worse A participant scoring a 1 or 2 is considered a responder on the CGI scale. For the change in response status over time, a generalized estimating equation (GEE) model was used.

Secondary Outcome Measures

Name	Time	Method
Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease - Rating Scale (QUIP-RS)	The QUIP-RS was administered at baseline and the termination visits (Visit 5, 8 weeks after baseline).	The Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) was developed for use in clinical trials and added as a secondary outcome measure for assessment of change in severity of ICD symptoms, to be completed at baseline and end of study only. For the QUIP-RS, scores for each compulsive behavior range from 0 to 16, with a higher score indicating greater severity (frequency) of symptoms. Given that ICD symptoms are frequently comorbid in patients with PD, total QUIP-RS ICD scores (range from 0 to 64) were used to compare overall severity of ICD symptoms. Please note that this measure is reporting a change from baseline.