Narcolepsy is a long-term sleep disorder that causes excessive daytime sleepiness (EDS), which can make it hard to stay awake during the day. Other symptoms include sleep paralysis, hallucinations while falling asleep or waking up, and disrupted sleep.
Both main types of narcolepsy cause EDS, but they differ in other ways, such as:
- People with type 1 usually have cataplexy, which is a sudden, brief episode of muscle weakness. It’s often triggered by strong emotions, such as laughter, excitement, or fear. Narcolepsy type 1 is also linked to very low levels of orexin, a group of chemical messengers in the brain. Without enough orexin signaling, the brain has a harder time staying alert and controlling the switch between sleeping and waking.
- Narcolepsy type 2 does not cause cataplexy, and orexin levels are generally normal.
A medicine called Orzeyful (oveporexton) can be prescribed for adults to treat narcolepsy type 1. It is the first medicine that specifically targets the loss of orexin signaling linked to narcolepsy type 1.
Note: As of August 2026, Orzeyful has been approved by the FDA, but it is still being reviewed by the Drug Enforcement Administration (DEA) for scheduling as a controlled substance. This means the DEA will decide how strictly the medicine will be regulated based on its potential for misuse. Orzeyful will not be available until after the DEA makes this decision.
Below are common questions and answers about Orzeyful, including how it works, how to take it, and what benefits were seen in clinical studies.
How Does Orzeyful Work for Narcolepsy Type 1?
Orexin is a chemical messenger made in the brain that helps the brain regulate wakefulness, sleep, and muscle control.
People with narcolepsy type 1 lose many of the brain cells that make orexin. As a result, the brain does not receive enough orexin signaling to properly control the transitions between sleep and wakefulness.
Orzeyful is an orexin receptor 2 agonist. This means it activates the same type of receptor that the body’s natural orexin normally activates. By turning on this receptor, Orzeyful helps restore some of the orexin signaling that is missing in people with narcolepsy type 1.
How Orzeyful works is specifically aimed at the underlying cause of narcolepsy type 1. Orzeyful has been studied and approved for narcolepsy type 1, not type 2.
How Do I Take Orzeyful?
Orzeyful is a tablet that is taken by mouth. It comes in three strengths: 0.5 milligrams (mg), 1 mg, and 2 mg. Your health care provider will tell you how much to take and when.
Typically, the recommended dosage of Orzeyful is either 1 mg twice daily or 2 mg twice daily.
You take the first dose after waking up and the second dose three to five hours later. It’s best to take your doses at about the same time every day. For example, your prescriber may instruct you to take your first dose after waking up at 7 a.m. and your second dose at 11 a.m. To help you remember to take it on the same schedule every day, you may want to set an alarm. Also, try to follow these:
- Swallow the tablets whole with water. Do not split, crush, or chew them.
- Take Orzeyful with or without food.
- If you miss a dose, skip it. Take your next dose at the regular scheduled time. Do not take two doses at the same time.
The maximum dosage is 4 mg per day. Some people may need a lower dose of Orzeyful. This is because certain other medicines can interact with Orzeyful. So, check with your health care provider before making any changes to how you take it, and let them know about any medicines or supplements you take.
How Was Orzeyful Studied for Narcolepsy Type 1?
Orzeyful was studied in two clinical trials that included a total of 273 people with narcolepsy type 1.
Participants were randomly assigned to take Orzeyful or a placebo. The placebo tablet looked the same but had no active medicine in it. Neither the participants nor the researchers knew which treatment each person received during the study. Both studies lasted 12 weeks.
Study 1 participants were assigned to take either placebo, Orzeyful 1 mg twice daily, or Orzeyful 2 mg twice daily. Study 2 participants were assigned to take either placebo or Orzeyful 2 mg twice daily. In both studies, the two doses were taken at least three hours apart, with the second dose taken no later than 1 p.m.
Everyone in both studies had narcolepsy type 1 based on standard diagnostic criteria. Here are some details about the study participants:
Study 1. Their average age was 31 years, with ages ranging from 16 to 65 years. About 58% were female, and the rest were male. About 35% were White, 16% were Asian, 4% were Black or African American, and less than 1% identified with more than one race. Race was unknown or not reported for 44% of participants. About 8% were Hispanic or Latino, 45% were not Hispanic or Latino, and ethnicity was unknown or not reported for 47%.
Study 2. Their average age was 31 years, with ages ranging from 18 to 62 years. About 48% were female, and the rest were male. About 45% were White and 20% were Asian, while race was unknown for 35% of participants. About 65% were not Hispanic or Latino, while ethnicity was unknown or not reported for 35%.
The main goal of the studies was to see how much longer people could stay awake during the day after 12 weeks of treatment compared with before treatment. This was measured using the Maintenance of Wakefulness Test (MWT). This test measures how long a person can stay awake in a quiet, darkened room during several daytime sessions. Longer average times mean a better ability to stay awake, and an increase of more than two minutes from the start of the study was considered a meaningful improvement.
The studies also looked at many other outcomes, including:
Daytime sleepiness. Researchers used the Epworth Sleepiness Scale (ESS), an eight-question survey that asks how likely someone is to fall asleep during common daily activities. Lower scores mean less daytime sleepiness.
Cataplexy attacks. Participants recorded their cataplexy episodes in a daily diary. Researchers used these reports to calculate the average number of attacks each week. A 25% or greater decrease in cataplexy episodes was considered a meaningful improvement.
Overall severity of narcolepsy symptoms and overall rating of changes. Participants completed a survey that looked at several aspects of narcolepsy, including daytime sleepiness, cataplexy, sleep paralysis, hallucinations, and disrupted nighttime sleep. The total score gives an overall picture of how severe the person’s symptoms are. Participants also rated their overall narcolepsy symptoms after treatment compared with how they felt at the start of the study.
Before treatment began, people in the studies could stay awake for only about four to six minutes on average during the MWT. They were also having an average of about 33-49 cataplexy attacks per week.
What Are the Benefits of Orzeyful Based on Studies?
After 12 weeks of treatment, both studies showed that Orzeyful improved daytime wakefulness, sleepiness, cataplexy, and overall narcolepsy symptoms compared with placebo.
Better ability to stay awake
- In study 1, people taking Orzeyful 1 mg twice daily were able to stay awake about 14 minutes longer on the MWT than those taking placebo. Those taking Orzeyful 2 mg twice daily stayed awake about 17 minutes longer than the placebo group.
- In study 2, people taking Orzeyful 2 mg twice daily stayed awake about 20 minutes longer than those taking placebo.
Less daytime sleepiness
- In study 1, sleepiness scores (ESS) improved by about 8 points more with the 1-mg dose and about 10 points more with the 2-mg dose compared with placebo.
- In study 2, scores improved by about 9.5 points more with Orzeyful than with placebo.
Fewer cataplexy attacks
- In study 1, people taking Orzeyful 1 mg had an average of about nine cataplexy attacks per week, while those taking 2 mg had about 13. In comparison, people taking placebo had about 28 attacks per week.
- In study 2, people taking Orzeyful had an average of about seven cataplexy attacks per week at week 12, compared with about 29 attacks per week with placebo.
Overall improvement
- People taking Orzeyful had greater improvements in the overall severity of narcolepsy symptoms, including daytime sleepiness, cataplexy, sleep paralysis, hallucinations, and disrupted nighttime sleep, compared with those taking placebo. Participants taking Orzeyful were also more likely to report improvement in their narcolepsy symptoms compared with those taking placebo.
Overall, the studies showed that Orzeyful works better than a placebo for treating narcolepsy type 1, based on improvements in daytime wakefulness, cataplexy, and other symptoms of the condition.
The studies found no clear difference in how well Orzeyful worked in males vs. females. There was not enough information to tell whether its effects differed by race or ethnicity.
Your results may vary from the results seen in studies. Your health care provider can help you decide whether Orzeyful may be an option for you.
What Are Other Unique Considerations to Be Aware Of?
A few other things are worth knowing before starting Orzeyful. It can sometimes cause trouble sleeping and may increase how often or how urgently you need to pee. Unexplained muscle pain, weakness, or dark urine should also be reported to a health care provider.
Orzeyful also has the potential for misuse or abuse and may be classified as a controlled substance after review by the DEA. If you have a history of substance use disorder or stimulant misuse, tell your health care provider before starting Orzeyful.
Orzeyful can interact with some prescription and nonprescription medicines, vitamins, and herbal products, so make sure your health care provider knows everything you take before starting or stopping anything. For more details, see our article on Orzeyful side effects and drug interactions.
