8 Belsomra Side Effects You Should Know About

Insomnia is a common sleep disorder that makes it hard to fall asleep, stay asleep, or both. If you’ve tried improving your sleep hygiene but still aren’t sleeping well, your healthcare team may suggest trying sleep medication. One option they may consider is Belsomra (suvorexant).

Belsomra is a prescription medication that can help promote sleep. It works by blocking the actions of orexin, a chemical in your brain that helps you feel awake. Like most sleep medications, Belsomra carries a risk of side effects. When starting Belsomra, it’s good to know what side effects are possible.

Belsomra side effects at a glance

Most Belsomra side effects are mild and tend to get better the longer you take it. But some side effects are more serious and need medical attention right away.

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Common Belsomra side effects include:

• Drowsiness

• Dizziness

• Headache

• Dry mouth

• Unusual dreams

Less commonly, Belsomra can cause other mild side effects:

• Diarrhea

• Cold-like symptoms

• Cough

Rare but serious Belsomra side effects include:

• Sleep paralysis

• Hallucinations

• Slowed breathing

• Complex sleep behaviors, such as sleepwalking

• New or worsening depression

• Suicidal thoughts

Below, we’ll dive deeper into eight Belsomra side effects. Keep in mind, this isn’t a complete list of all possible side effects. If you’re unsure about a symptom you’re experiencing, check with your prescriber for next steps.

EXPERT PICKS: WHAT TO READ NEXT

• Is Belsomra a controlled substance? Read pharmacists’ answers to this and other frequently asked questions about Belsomra.

• Beating insomnia: Learn about three people’s experiences with insomnia and how they were able to get the sleep they needed.

• Getting the right dose: Belsomra has a standard recommended dosage, but medication interactions can affect how much you should take.

1. Drowsiness

Like other sleep medications, Belsomra can cause drowsiness. This side effect is intended and is why you’re taking the medication.

You may start feeling tired or drowsy within 30 minutes of taking Belsomra. The medication stays active in your body for up to 12 hours after taking it. This can cause next-day drowsiness or fatigue. To lower the risk of experiencing next-day effects, only take Belsomra if you can devote at least 7 hours to sleep.

Because of this side effect, Belsomra can impair your driving the next day. In fact, Belsomra’s manufacturer recommends that people taking the highest (20 mg) dose shouldn’t drive the day after taking it.

Avoid combining Belsomra with other substances that cause drowsiness, such as opioid pain relievers or alcohol. Doing so can make drowsiness more severe or potentially dangerous.

Let your prescriber know if you feel excessively drowsy after taking Belsomra. They may suggest lowering your dose or trying a different sleep medication.

2. Dizziness

Dizziness is another common Belsomra side effect. It happens more frequently in older adults and those taking higher doses.

Dizziness on its own isn’t dangerous. But it can raise the risk of falls or accidental injury, especially in older adults. Take Belsomra only when you’re ready to go to sleep. Dizziness may be worse if you get out of bed after Belsomra starts working.

Take care to stand slowly when you get up the next morning. You may still feel dizzy the next day even if you’ve slept for the recommended amount of time. Tell your prescriber if you experience severe dizziness while taking Belsomra.

3. Headache

Headaches are another common Belsomra side effect. This side effect has more often been reported by women and people who take higher doses. Headaches should be mild in nature. They may be more noticeable when you first start Belsomra or shortly after raising your dosage. Typically, headaches will get better as your body adjusts to the medication.

If you experience headaches with Belsomra, try these tips to help manage them at home:

• Drink plenty of water or other fluids.

• Make sure you’re getting at least 7 hours of sleep after taking Belsomra.

• Avoid foods that can trigger or worsen headaches, such as alcohol.

• Ask a healthcare professional whether you can take over-the-counter pain relievers, such as acetaminophen (Tylenol).

Talk to your prescriber if your headaches seem severe or don’t get better. There could be another cause for your symptoms.

4. Dry mouth

Dry mouth is another common Belsomra side effect. In clinical trials, women reported it more frequently than men. Dry mouth from Belsomra is typically mild and may improve with time.

Dry mouth can be uncomfortable. And over time, it can lead to dental problems. Drinking more water and sucking on sugar-free candy are things you can try to reduce the feelings of dry mouth.

If at-home remedies aren't enough, let your healthcare team know. They can provide further management tips or medication adjustments if needed.

5. Unusual dreams

Like other sleep medications, Belsomra may cause you to have unusual or abnormal dreams. Like other Belsomra side effects, unusual dreams have been reported more often by women  than men.

Having an occasional abnormal dream after taking Belsomra typically isn’t a huge concern. But if your dreams are too intense or upsetting, let your prescriber know. You may need a dosage adjustment.

Good to know: Sometimes, unusual dreams can happen along with more serious sleep-related Belsomra side effects. These include hallucinations when waking up and complex sleep behaviors, such as sleep walking. If you’re having abnormal dreams along with these other side effects, let your prescriber know right away.

6. Sleep paralysis

Less commonly, Belsomra can cause sleep paralysis. Sleep paralysis is when you can’t move your body or speak when falling asleep or waking up.

Sleep paralysis can be scary. You feel awake but physically “paralyzed,” and you can’t do anything about it. Episodes of sleep paralysis typically last from a few seconds to a few minutes. Then, you naturally wake from them on your own.

Some people also experience hallucinations during episodes of sleep paralysis. You may see, hear, or feel people or things that aren’t in the room with you. You may or may not know that you’re hallucinating. And this can be frightening while it’s happening.

Unlike some other Belsomra side effects, you shouldn’t wait to see if this gets better on its own. Tell your healthcare team if you experience sleep paralysis or hallucinations while taking Belsomra. You may need a dosage or medication change.

7. Sleepwalking

Complex sleep behaviors (parasomnias) are a rare but serious Belsomra side effect. They include performing actions while sleeping, such as sleepwalking, sleep eating, or sleep driving. Parasomnias can be dangerous since you’re unaware that you’re performing these activities while sleeping.

Talk to your prescriber right away if you experience complex sleep behaviors while taking Belsomra. You’ll likely need to stop taking the medication.

8. Suicidal thoughts

Very rarely, Belsomra may cause or worsen symptoms of depression. People have also reported suicidal thoughts while taking the medication. This is a serious Belsomra side effect that warrants immediate medical attention.

If you notice a negative change in your mood or behaviors, let your prescriber know right away. You should also tell them if you have a history of depression or suicidal thoughts before starting Belsomra. It may not be the right sleep medication for you.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

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Written by:

Kristine Foley, PharmD

Kristine Foley is a licensed pharmacist with over 13 years of community pharmacy experience. She earned her Doctor of Pharmacy degree from Rutgers University.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Jennifer Gershman, PharmD, CPh, PACS

Jennifer Gershman, PharmD, is a licensed pharmacist in Florida. She has worked in the pharmacy industry for more than 15 years and is currently a medical writer.

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