Naltrexone for impulse control disorders in Parkinson disease: a
placebo-controlled study.
Author(s): Papay K(1), Xie SX(1), Stern M(1), Hurtig H(1), Siderowf A(1), Duda JE(1), Minger
J(1), Weintraub D(2).
Affiliation(s): Author information:
(1)From the Departments of Psychiatry (K.P., D.W.), Biostatistics and
Epidemiology (S.X.X.), and Neurology (M.S., H.H., J.E.D., J.M.), University of
Pennsylvania, Philadelphia; Avid Radiopharmaceuticals (A.S.), Philadelphia; and
Parkinson's Disease Research, Education and Clinical Center (J.E.D., D.W.),
Philadelphia Veterans Affairs Medical Center, PA. (2)From the Departments of
Psychiatry (K.P., D.W.), Biostatistics and Epidemiology (S.X.X.), and Neurology
(M.S., H.H., J.E.D., J.M.), University of Pennsylvania, Philadelphia; Avid
Radiopharmaceuticals (A.S.), Philadelphia; and Parkinson's Disease Research,
Education and Clinical Center (J.E.D., D.W.), Philadelphia Veterans Affairs
Medical Center, PA. daniel.weintraub@uphs.upenn.edu.
Publication date & source: 2014, Neurology. , 83(9):826-33
OBJECTIVE: Impulse control disorders (ICDs) in Parkinson disease (PD) are common
and can be difficult to manage. The objective of this study was to determine the
efficacy and tolerability of naltrexone, an opioid antagonist, for the treatment
of ICDs in PD.
METHODS: Patients with PD (n = 50) and an ICD were enrolled in an 8-week,
randomized (1:1), double-blind, placebo-controlled study of naltrexone 50-100
mg/d (flexible dosing). The primary outcome measure was response based on the
Clinical Global Impression-Change score, and the secondary outcome measure was
change in symptom severity using the Questionnaire for Impulsive-Compulsive
Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) ICD score.
RESULTS: Forty-five patients (90%) completed the study. The Clinical Global
Impression-Change response rate difference favoring naltrexone in completers was
19.8% (95% confidence interval [CI] -8.7% to 44.2%). While this difference was
not significant (odds ratio=1.6, 95% CI 0.5-5.2, Wald χ2 [df]=0.5 [1], p=0.5),
naltrexone treatment led to a significantly greater decrease in QUIP-RS ICD score
over time compared with placebo (regression coefficient for interaction term in
linear mixed-effects model=-7.37, F[df]=4.3 [1, 49], p=0.04). The estimated
changes in QUIP-RS ICD scores from baseline to week 8 were 14.9 points (95% CI
9.9-19.9) for naltrexone and 7.5 points (95% CI 2.5-12.6) for placebo.
CONCLUSIONS: Naltrexone treatment was not efficacious for the treatment of ICDs
in PD using a global assessment of response, but findings using a PD-specific ICD
rating scale support further evaluation of opioid antagonists for the treatment
of ICD symptoms in PD.
CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in patients
with PD and an ICD, naltrexone does not significantly increase the probability of
achieving response. However, the study lacked the precision to exclude an
important difference in response rates.
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