Belsomra side effects: What you should know

Belsomra can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Belsomra in clinical trials:

• headache
• next-day drowsiness*

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Belsomra. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Belsomra’s prescribing information.

Mild side effects that have been reported with Belsomra include:

• headache
• dry mouth
• diarrhea
• upper respiratory infection
• cough
• unusual dreams
• dizziness*
• next-day drowsiness*
• mild allergic reaction*

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Belsomra and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Belsomra may cause serious side effects. These side effects aren’t common, but their risk increases with higher doses of Belsomra. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Belsomra’s prescribing information.

If you develop serious side effects while taking Belsomra, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

• Excessive sedation. Symptoms can include:
  • severe drowsiness
  • reduced coordination, which may lead to falls and injuries
  • reduced alertness, making it dangerous to drive, use machinery, or perform other potentially hazardous tasks that require mental focus
• Temporary muscle weakness. Symptoms can include:
  • sudden weakness in your legs or other muscles that can last up to a few minutes
  • suddenly going limp or falling to the ground
• Suicidal thoughts or behaviors and worsened depression. Symptoms can include:
  • thinking about harming yourself
  • changes in mood or behavior
• Unusual sleep behaviors, such as sleepwalking.*
• Other problems during sleep, such as sleep paralysis and hallucinations.*
• Severe allergic reaction.†

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Belsomra. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Belsomra may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Can Belsomra cause weight loss or weight gain?

No, Belsomra shouldn’t cause weight loss or weight gain. These weight changes weren’t reported in the drug’s clinical trials.

If you have concerns about changes in your weight while taking Belsomra, talk with your doctor.

Will Belsomra 10 mg cause fewer side effects than the drug’s other strengths?

It’s possible. The risk of Belsomra’s side effects typically increases at higher strengths. The dose of Belsomra ranges from 5 milligrams (mg) to 20 mg, taken at bedtime. The drug comes in four strengths and doses: 5 mg, 10 mg, 15 mg, and 20 mg.

For example, it’s common to feel drowsy the day after taking Belsomra. This side effect is more likely to occur and become severe at high doses of the drug. If your doctor prescribes the 20-mg strength, they will likely advise you not to drive or perform other activities requiring mental alertness.

If you have questions about the risk of side effects with your dosage, talk with your doctor.

How do side effects of Belsomra in older adults compare with those seen in younger adults?

In clinical trials, Belsomra treatment caused the same types of side effects in older adults (ages 65 years and over) as in younger adults.

However, older adults may have a higher risk of complications from certain side effects. For example, Belsomra may cause dizziness, next-day drowsiness, and excessive sedation. These side effects may occur in people of any age, but older adults may be more likely than younger adults to fall as a result. This may cause serious injury, such as a hip fracture. Due to this risk, doctors typically prescribe a low dosage of Belsomra for older adults.

Learn more about some of the side effects that Belsomra may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Belsomra.

Next-day drowsiness

Belsomra is taken at bedtime to help treat insomnia. This drug may cause drowsiness the day after it’s taken. This side effect is also known as somnolence. It was the most common side effect reported in the drug’s clinical trials.

Symptoms include feeling more sleepy or less attentive than is typical for you.

The risk of next-day drowsiness increases at higher doses of Belsomra. This risk also increases if you use other medications that depress your central nervous system. It’s also increased if you drink alcohol and take a dose of Belsomra.

Keep in mind that insomnia, which Belsomra is prescribed to treat, causes trouble sleeping. This condition may also make you feel sleepy the next day.

What you can do

To decrease the risk of next-day drowsiness, only take Belsomra when you have time to sleep for at least the next 7 hours. This gives the drug time to wear off before you need to wake up and start your day.

Talk with your doctor if you’re experiencing next-day drowsiness while taking Belsomra. They may lower your dosage or suggest other ways to treat your insomnia.

Dizziness

Taking Belsomra may cause dizziness. This side effect was reported in the drug’s clinical trials, but it wasn’t common.

Symptoms of dizziness may include:

• lightheadedness
• unsteadiness as you walk or move
• a sensation of spinning or motion when you’re not moving

What you can do

Belsomra is prescribed to treat insomnia. You’ll take it at bedtime when you can spend at least the next 7 hours asleep. To help prevent dizziness, try to stay in bed for at least 7 hours after taking Belsomra, even if you have trouble falling asleep or if you wake up too early. Getting up and moving around may make dizziness more noticeable or bothersome.

If you become dizzy, try to sit or lie down as soon as possible to help prevent falling and injury.

If you have dizziness that concerns you during Belsomra treatment, talk with your doctor. They may prescribe a lower dosage or suggest other ways to treat your insomnia.

Unusual sleep behaviors

Taking Belsomra may increase the risk of parasomnia (unusual behaviors during sleep). These involve getting out of bed and engaging in activities, all while not being fully awake.

This side effect wasn’t seen in Belsomra’s clinical trials, but is still possible. These behaviors have been reported with other medications prescribed to treat insomnia. (Belsomra is also prescribed to treat this condition.)

Examples of unusual sleep behaviors that have been reported include:

• sleepwalking
• sleep driving
• sleep sex
• cooking and eating
• making phone calls

Most people who have experienced these behaviors don’t recall doing them. If you live with other people, consider telling them about your medication and the unusual behaviors that it might cause. This way, they can let you know if unusual behaviors occur.

What you can do

Engaging in these activities, especially driving, while not being fully awake and alert can be dangerous. After taking Belsomra, it’s important not to drive for at least 8 hours. Before taking your dose at bedtime, consider putting your car keys in a secure place to help prevent yourself from getting to them.

If you or your household members notice unusual behaviors, tell your doctor right away. They’ll likely have you stop taking Belsomra. They can suggest other safe ways to treat your insomnia.

Other problems during sleep

Belsomra may cause problems related to sleep, including sleep paralysis and hallucinations. They may occur just as you’re falling asleep or waking up.

With sleep paralysis, you aren’t able to move or talk for up to several minutes. Sleep paralysis can happen when part of your brain fully wakes up before the part of the brain that controls your muscle movements.

With hallucinations, you may perceive things that aren’t real. For example, you might hear a voice or see something that isn’t really there.

In some cases, hallucinations and sleep paralysis may occur at the same time. These experiences can be frightening or disturbing.

Some people reported these problems in the drug’s clinical trials. It isn’t clear how often they occurred. These side effects have also been reported in people taking other medications to treat insomnia.

What you can do

Learning about a drug’s side effects can help you know what to expect. Reading about potential side effects of Belsomra may help you feel less frightened if they occur.

If these side effects occur and feel severe or bothersome, talk with your doctor. They may have you take a lower dose or have you stop taking Belsomra. If necessary, they can suggest other ways to manage your insomnia.

Allergic reaction

As with most drugs, Belsomra can cause an allergic reaction in some people. However, this side effect wasn’t reported in clinical trials.

Symptoms can be mild or serious and can include:

• skin rash
• itching
• flushing
• swelling under your skin, typically in your eyelids, lips, hands, or feet
• swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Belsomra. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Belsomra. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Allergic reaction. If you’ve had an allergic reaction to Belsomra or any of its ingredients, your doctor will likely not prescribe Belsomra. Ask your doctor what other medications may be better options for you.

Breathing problems. If you have a condition that affects your breathing, taking Belsomra may worsen your symptoms. Examples are chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea. To learn more about these risks and decide whether Belsomra is safe for you, talk with your doctor.

Cataplexy. Although rare, Belsomra can cause sudden muscle weakness as a side effect. This side effect is similar to a symptom of cataplexy (sudden, brief loss of muscle control). If you already have cataplexy, taking Belsomra may make this symptom worse. Your doctor can provide guidance on safe treatment options for insomnia.

Females with obesity. Belsomra may have stronger effects in females* than in males.* In addition, Belsomra may also have stronger effects in people with obesity than in those without obesity. Having both of these factors may increase your risk of side effects. Doctors may monitor your condition closely for side effects if you are female, have obesity, and take Belsomra.

History of substance use disorder. Belsomra may not be right for you if you have or have had an alcohol or substance use disorder. This is because Belsomra is a controlled substance and carries risks of misuse and dependence. Misuse is taking a drug in a way other than how a doctor prescribes it. With dependence, your body needs the drug to function as it typically would.

Dependence is possible even if you take a drug exactly as prescribed. However, these risks may be higher in people with a history of substance use disorder. It’s important to talk with your doctor about your history. This will help them recommend treatment options for your insomnia that are safe for you.

History of suicidal tendencies or depression. Taking Belsomra may cause suicidal thoughts or behaviors. The drug may also worsen depression. If you have been diagnosed with depression or think you have depression, talk with your doctor. They can tell you more about these risks and help decide whether Belsomra is safe for you.

Liver problems. It isn’t known whether Belsomra is safe for people with severe liver problems. If you have or had liver problems, talk with your doctor. They can determine whether your liver problems are severe. If so, they may recommend other treatment options for your condition.

Narcolepsy. Narcolepsy is a sleep disorder that causes excessive daytime sleepiness. Belsomra is a drug prescribed to help people with insomnia fall asleep or stay asleep. If you have narcolepsy, taking Belsomra could worsen your symptoms. Due to this risk, doctors typically will not prescribe Belsomra to people with narcolepsy.

Older age. Taking Belsomra may cause next-day drowsiness or other side effects. If you’re age 65 years or older, this may increase your risk of falls. If you’re an older adult and have concerns about this side effect, talk with your doctor. They may prescribe a low dosage and monitor your condition closely during treatment.

* Sex and gender exist on spectrums. Use of the terms “female” and “male” in this article refers to sex assigned at birth.

Alcohol with Belsomra

As with other medications taken to treat insomnia, you should not consume alcohol with Belsomra. If you drink alcohol during Belsomra treatment, skip your dose of Belsomra that evening before you go to bed.

Drugs prescribed to treat insomnia, including Belsomra, may cause central nervous system (CNS) depression, especially at high doses. This means they can slow down certain brain functions and reduce your ability to think, talk, walk, and breathe as you typically would.

Alcohol may also cause CNS depression, especially when consumed in large amounts. So taking Belsomra and alcohol together may further increase the risk and severity of CNS depression.

If you have questions about consuming alcohol while taking Belsomra, talk with your doctor.

Pregnancy and breastfeeding while taking Belsomra

It’s unknown whether Belsomra is safe to take during pregnancy.

If you’re pregnant or planning to become pregnant, talk with your doctor before taking Belsomra. They may recommend other ways to treat your insomnia.

It’s also not known whether it’s safe to take Belsomra while breastfeeding.

In animal studies of suvorexant, the active drug in Belsomra, the drug passed into the milk of lactating rats. Based on this finding, it’s possible that Belsomra may pass into human breast milk.

A child who’s breastfed by a person taking Belsomra may experience side effects of the drug, such as excessive sedation. However, animal studies don’t always predict what may happen in humans.

If you’re breastfeeding or planning to, talk with your doctor. They may recommend other treatments for insomnia or safe feeding options for your child.

Belsomra is classified as a Schedule IV controlled substance. Controlled substances are regulated by the government because taking them can lead to misuse and dependence. Misuse is taking a drug in a way other than how a doctor prescribes it. With dependence, your body needs the drug to function as it typically would. Dependence is possible even if you take a drug exactly as prescribed.

However, in clinical trials, there were no reports of misuse or physical dependence with long-term Belsomra treatment.

People with a history of substance use disorder may have a higher risk of drug misuse or dependence. If you have concerns about your risk, be sure to discuss your medical history with your doctor before starting Belsomra. They’ll help you determine whether this medication is right for you.

Belsomra may cause side effects, but its side effects are typically mild when taken as prescribed.

If you’d like to learn more about Belsomra, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

• More information about Belsomra. For details about other aspects of Belsomra, refer to this article.
• A look at insomnia. For details about insomnia, see our science of sleep hub.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.