Hypersomnolence is a condition in which people are excessively sleepy to the degree that they cannot sustain the level of alertness necessary to accomplish activities of daily living. These individuals typically fall asleep unintentionally in inappropriate situations. Sometimes, because of the condition, there’s a heightened degree of danger while driving or operating heavy equipment at work. In children, though, the sleepiness associated with this condition could be manifested as hyperactivity.
Excessive sleepiness is common in the United States — five percent of the general population complains of excessive sleepiness. The most common cause is insufficient sleep. Under these circumstances the condition is identified as insufficient sleep syndrome.
There are, however, some sleep disorders that are associated with symptoms of excessive sleepiness during waking hours. They include narcolepsy, which is caused by a deficiency of the hormone, orexin, that is responsible for keeping us awake during daytime.
Another condition, idiopathic hypersomnolence, can occur for a variety of reasons even after there is adequate amount of sleep at night. The term idiopathic means we don’t know the precise cause or causes. These individuals actually sleep for normal or longer periods at night and still feel excessively sleepy during the daytime. Currently there are not many options for treatment so the current approach is to treat the consequences.
Cataplexy is a condition in which a strong emotional experience can cause the person to suffer sudden physical collapse, though they remain conscious. There are specific medications that treat this sleep-related condition.
There are also medications for the daytime sleepiness associated with the various sleep disorders mentioned above. They include Ritalin and amphetamines, medications that unfortunately have many undesirable side effects. The most commonly used medication for excessive daytime sleepiness is modafinil (Provigil) but it is very expensive and it too has many undesirable side effects.
Therefore, the search for better drugs has continued.
Data from the phase three placebo-controlled trial of a drug called solriamfetol was presented in discussion at the 2018 American Academy of Neurology Annual Meeting in April 2018 in Los Angeles. Back in 2017, the drug had shown some promise for promoting wakefulness and reducing daytime sleepiness in patients with obstructive sleep apnea (OSA) who had not responded well to traditional therapy.
Solriamfetol was initially developed as an antidepressant, a drug in the class of selective norepinephrine reuptake inhibitor (DNRI), similar to Effexor and Abilify. In its initial trials as a treatment for depression, it’s wake-promoting properties were observed by researchers. There was profound interest in this drug because it works by affecting different pathways from traditional wake-promoting drugs, so it had the potential to avoid the known undesirable side effects including the addictive nature of some of the current drug treatments.
In fact, the robust nature of the wakeful effects of the drug, and the safety profile of solriamfetol, suggested that it could be used in other disorders that produce sleepiness like Parkinson’s disease.
The phase 3 trial that enabled the drug to obtain the FDA indication for treatment of excessive somnolence, despite its falling into the antidepressant category, included one study evaluating patients with narcolepsy, two studies involving patients with OSA, and one study which was an open-label long term safety and efficacy study. There is also one separate study looking at the role solriamfetol might have in treating excessive sleepiness specifically in patients diagnosed with Parkinson’s disease.
Researchers saw a significant improvement in the subjective assessment of daytime sleepiness as measured by the Epworth Sleepiness Scale, a questionnaire that asks individuals to rate their chances of dozing off during eight different situations, during waking hours. This finding was confirmed by objective data obtained by having the subjects undergo a Multiple Sleep Latency Test MSLT — a study conducted in a sleep lab that provides concrete measurable data.
The results of these studies, cumulatively, showed a significant improvement in the subjects suffering with the different causes of daytime sleepiness, namely narcolepsy and OSA.
The availability of this new agent is exciting because there have not been any new agents for the treatment of daytime sleepiness. As of now, the FDA has only approved solriamfetol for these specific indications because these were the only “sleep” situations in which it has been tested.
Given that this is an antidepressant with similar properties and mechanism of action as other commonly used antidepressants, it is expected that more testing will be done on the drug to potentially lead to more indications. Since OSA has been linked to depression, one could conjecture that this drug may have especially unique benefits for these patients, given its impact on promoting wakefulness and the fact that it is an antidepressant.
It’s important to note that there is no replacement for a healthy environment that supports a regular schedule that will enable adequate, restful and restorative sleep. Though we need an arsenal of safe drugs, committing to sleep hygiene is the safest and healthiest way to get your zzz’s.