Zolpidem induces paradoxical metabolic and vascular changes in a patient with PVS

August 2013

Rafael Rodriguez-Rojas
Calixto Machado
Lazaro M Alvarez
Philip A Defina
…and others.

ABSTRACT: Introduction: Zolpidem is a non-benzodiazepine drug used for the therapy of insomnia, which has selectivity for stimulating the effect of GABA-A receptors. Recently, a paradoxical arousing effect of zolpidem in patients with severe brain damage has been repeatedly reported. Methods: A placebo-controlled magnetic resonance study was conducted to evaluate its effect on BOLD and metabolites spectral signals in a patient with severe brain injuries and an age-matched healthy volunteer. A multi-modal analysis was used to assess aspects in the pharmacologically-induced changes in the resting-state brain metabolism. Results: A significantly increased BOLD signal was transiently localized in the left frontal cortices, bilateral anterior cingulated areas, left thalamus and right head of the caudate nucleus. The healthy subject showed a deactivation of the frontal, parietal and temporal cortices. BOLD signal changes were found to significantly correlate with concentrations of extravascular metabolites in the left frontal cortex. It is discussed that, when zolpidem attaches to modified GABA receptors of neurodormant brain cells, brain activation is induced. This might explain the significant correlations of BOLD signal changes and proton-MRS metabolites in this patient after zolpidem. Conclusion: It was concluded that proton-MRS and BOLD signal assessment could be used to study zolpidem-induced metabolic modulation in a resting state.

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Zolpidem Arousing Effect In Persistent Vegetative State Patients: Autonomic, Eeg And Behavioral Assessment

September 2013

Current pharmaceutical design 20(26)
DOI: 10.2174/13816128113196660646
SourcePubMed
Project: PVS / MCS
Philip A. DeFina
Calixto Machado
Mario Estévez
Rafael Rodriguez-Rojas
Nuvia Pérez-Cruz

ABSTRACT: Objective: To study the Zolpidem arousing effect in persistent vegetative state (PVS) patients combining clinical evaluation, autonomic assessment by heart rate variability (HRV), and EEG records. Methods: We studied a group of 8 PVS patients and other 8 healthy control subjects, matched by age and gender. The patients and controls received drug or placebo in two experimental sessions, separated by 10-14 days. The first 30 minutes of the session were considered the basal record, and then Zolpidem was administered. All participants were evaluated clinically, by EEG, and by HRV during the basal record, and for 90 minutes after drug intake. Results: We found in all patients, time-related arousing signs after Zolpidem intake: behavioral (yawns and hiccups), activation of EEG cortical activity, and a vagolytic chronotropic effect without a significant increment of the vasomotor sympathetic tone. Conclusions: We demonstrated time-related arousing signs after Zolpidem intake. We discussed possible mechanisms to explain these patho-physiological findings regarding EEG cortical activation and an autonomic vagolytic drug effect. As this autonomic imbalance might induce cardiocirculatory complications, which we didn’t find in any of our patients, we suggest developing future trials under control of physiological indices by bedside monitoring. However, considering that this arousing Zolpidem effect might be certainly related to brain function improvement, it should be particularly considered for the development of new neuro-rehabilitation programs in PVS cases. According to the literature review, we claim that this is the first report about the vagolitic effect of Zolpidem in PVS cases.

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