Flumazenil for the Treatment of Refractory Hypersomnolence
In 2012, researchers from Emory University published a paper on their finding of a substance that increases the effect of GABA in people with central disorders of hypersomnolence, particularly idiopathic hypersomnia. In that paper, they discussed their findings in seven patients who were treated with flumazenil. In 2014, Kelty et al published a case report on the use of flumazenil given intravenously to a single patient for 96 hours and then implanted under the skin. The current paper from the group of Emory researchers includes information from additional patients who were treated with a compounded version of flumazenil.
What kind of a study was this?
This was a retrospective study, meaning that the researchers did not set out ahead of time to perform a research study with predetermined goals and questions. Instead, two neurologists prescribed the medication, flumazenil, as part of their routine practice to all appropriate patients who came to their clinic. Then, at a later date, they formulated their questions.
Who were the patients and what did they do?
One hundred fifty-three patients (92 women) were prescribed flumazenil by the physicians at Emory.
Their average age was 35.5 years. All of the patients completed the Epworth Sleepiness Scale (ESS) before starting treatment with flumazenil, and some patients completed a second ESS after starting treatments.
Who were the researchers and what did they do?
Dr. Trotti and her colleagues at Emory University reviewed the charts of their patients with hypersomnolence for whom they had prescribed flumazenil. They also reviewed the patients’ electronic correspondence and pharmacy records.
What were the results of the study?
Ninety-six of the 153 (63%) patients reported that they were less sleepy after taking flumazenil. On the other hand, 19 people reported that they were more sleepy after taking flumazenil. Among these 19 patients, nine continued taking flumazenil because the increased sleepiness was only temporarily worse right away after taking the medication or the sleepiness improved after the flumazenil dose was changed.
Before starting treatment, the average ESS score was 15.1, even among those who were taking wake-promoting agents. After starting treatment with flumazenil, the average ESS score dropped to 10.3 among the 40 people who reported improved sleepiness and who completed a second ESS.
Of the 96 patients who reported that their sleepiness improved in response to treatment with flumazenil, 59 continued to take the drug long term (average, 7.8 months at follow-up). Interestingly, 72% of women reported a positive response to the drug, whereas only 48% of men had a positive response. Similarly, people who reported having sleep inertia (difficulty waking up, including grogginess or disorientation immediately upon awakening) were more likely to respond to flumazenil, as compared with those without sleep inertia (72% vs 42%).
Seventy-nine participants (52%) reported experiencing an adverse event (the most common being dizziness, anxiety, and headache), with 17 people stopping the medicine because of adverse events. Two patients had serious adverse events, and another had changes in liver function tests that resolved after stopping the drug.
What were the researchers’ conclusions?
According to the authors of this study, “In summary, our clinical experience in a large group of patients with treatment-refractory hypersomnolence demonstrates meaningful and sustained clinical response in a substantial fraction of patients. Important questions remain about optimal formulation, dosing, long-term safety, and effectiveness. Prospective, controlled studies, ideally with measurement of plasma or cerebrospinal fluid flumazenil levels, are clearly needed. However, our experience suggests the possibility of clinical use of flumazenil in carefully selected, severely affected patients lacking other treatment options.”
Trotti LM, Saini P, Koola C, LaBarbera V, Bliwise DL, Rye DB. Flumazenil for the treatment of refractory hypersomnolence. J Clin Sleep Med 2016;ePub ahead of print.