Randomized, double-blind, placebo-controlled trial on symptomatic effects of coenzyme Q(10) in Parkinson disease.

BACKGROUND

Major hallmarks in the pathophysiology of Parkinson disease are cellular energy depletion and oxidative stress leading to cellular dysfunction and death. Coenzyme Q(10) (CoQ(10)) is an electron acceptor bridging mitochondrial complexes I and II/III and a potent antioxidant that consistently partially recovers the function of dopaminergic neurons.

OBJECTIVE

To determine whether nanoparticular CoQ(10) is safe and displays symptomatic effects in patients with midstage Parkinson disease without motor fluctuations.

DESIGN

Multicenter, randomized, double-blind, placebo-controlled, stratified, parallel-group, single-dose trial.

SETTING

Academic and nonacademic movement disorder clinics.

PATIENTS

One hundred thirty-one patients with Parkinson disease without motor fluctuations and a stable antiparkinsonian treatment. Intervention Random assignment to placebo or nanoparticular CoQ(10) (100 mg 3 times a day) for a treatment period of 3 months. Stratification criterion was levodopa treatment.

MAIN OUTCOME MEASURE

The subjects underwent evaluation with the Unified Parkinson's Disease Rating Scale (UPDRS) at each visit on a monthly basis. The primary outcome variable was the change of the sum score of the UPDRS parts II and III between the baseline and 3-month visits.

RESULTS

One hundred thirty-one subjects were randomized according to the protocol. The mean changes of the sum UPDRS parts II/III score were -3.69 for the placebo group and -3.33 for the CoQ(10) group (P = .82). Statistical analysis according to the stratification did not result in significant changes of the primary outcome variable. No secondary outcome measure showed a significant change between the placebo group and the CoQ(10) group. The frequency and quality of adverse events were similar in both treatment groups.

CONCLUSIONS

Nanoparticular CoQ(10) at a dosage of 300 mg/d is safe and well tolerated and leads to plasma levels similar to 1200 mg/d of standard formulations. Add-on CoQ(10) does not display symptomatic effects in midstage Parkinson disease.