Key takeaways

  • Mild side effects of Contrave include nausea, constipation, and headache.
  • Contrave can also cause serious side effects, though these are rare. Examples include increased blood pressure and mood changes.
  • Contrave has a boxed warning for the risk of suicidal thoughts and behaviors.

Contrave is a prescription drug used together with a low calorie diet and exercise to help manage weight in certain adults.

Contrave comes as a tablet that you swallow and is usually taken long term. It contains two active ingredients: naltrexone and bupropion. (An active ingredient is what makes a drug work.)

For more information about Contrave, including details about its uses, see this Contrave overview.

Like other drugs, Contrave can cause mild to serious side effects. Keep reading to learn more.

Some people may experience mild to serious side effects during their Contrave treatment. Examples of the drug’s commonly reported side effects include:

  • nausea
  • vomiting
  • dizziness
  • constipation
  • headache

To learn more about some of these side effects, see the “Side effects explained” section.

These are just a few of the more common side effects Contrave can cause. Keep reading for information about other possible mild and serious side effects of this drug. And note that not everyone who takes Contrave will have side effects from it.

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Mild side effects have been reported with Contrave. These include:

To learn more about some of these side effects, see the “Side effects explained” section.

In most cases, these side effects should be temporary, and some may be easily managed. But if you have symptoms that are ongoing or bother you, talk with your doctor or pharmacist. You should not stop taking Contrave unless your doctor recommends it.

Contrave may cause mild side effects other than those listed here. See the Contrave prescribing information for details.

Serious side effects have been reported with Contrave, but these were rare. They include:

Contrave has a boxed warning for risk of suicidal thoughts and behaviors. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effects explained” section.

If you develop serious side effects while taking Contrave, 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.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Contrave and want to tell the FDA about it, visit MedWatch or call 800-332-1088.

Get answers to some frequently asked questions about Contrave’s side effects.

Will I experience certain side effects during the first week of treatment with Contrave?

It’s likely. In studies, nausea was the most common side effect of Contrave. It may be more noticeable when you first start treatment, but this side effect will likely go away as your body gets used to the drug.

If nausea from Contrave does not go away or becomes severe, talk with your doctor. They can recommend ways to help manage this side effect. Or they may suggest changes to your dosage or treatment plan.

How long does it take for Contrave’s side effects to go away?

Contrave’s side effects usually become less noticeable after a few weeks of taking the drug. But how long side effects last can vary from person to person. It depends on several factors, such as your dosage and how your body responds to the drug.

Keep in mind that Contrave should be taken with a meal. But taking the drug with a high fat meal can increase the drug’s side effects, such as nausea. If Contrave’s side effects are not easing, you may want to check the fat content of the foods you’re consuming with each dose.

Talk with your doctor if you have bothersome side effects from Contrave that are not going away. They can suggest ways to manage them or adjust your dosage if needed.

If I stop taking Contrave, will I experience withdrawal symptoms?

No, stopping Contrave should not cause withdrawal symptoms. (These are uncomfortable side effects that can happen when you stop taking a drug your body is used to.)

In studies, researchers observed people who stopped Contrave suddenly as well as those who tapered off of it. (With drug tapering, your doctor will have you slowly reduce your dosage before you stop it.) No signs of withdrawal symptoms were seen in either group.

Still, it’s best to talk with your doctor before stopping Contrave. They can help you determine other ways to manage your weight. Besides diet and exercise habits, this may include switching to a different treatment option.

Does Contrave cause long-term side effects?

It’s not likely. If your doctor suggests you stop taking Contrave due to side effects, your symptoms should ease within a week after your last dose.

But Contrave does have a boxed warning regarding the risk of suicidal thoughts or behaviors. These can be associated with changes in a person’s moods and behaviors. (See the “Side effects explained” section for more information about this side effect and the warnings around it.)

Talk with your doctor right away if you have suicidal thoughts or changes in your mood or behavior. Your doctor will likely have you stop taking Contrave. They’ll also continue to monitor you after you stop taking it to ensure these symptoms go away.

Can Contrave cause sexual side effects?

Possibly. Sexual side effects were reported in studies of Contrave, but they were not common. These side effects included erectile dysfunction and vaginal dryness.

Sexual side effects may go away with time as your body gets used to the drug. If these side effects persist, talk with your doctor. For erectile dysfunction, they may prescribe a medication such as Viagra (sildenafil). For vaginal dryness, they may recommend using a lubricant.

Learn more about some of the side effects Contrave can cause.

Risk of suicidal thoughts and behaviors

Contrave has a boxed warning about the risk of suicidal thoughts and behaviors. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). They alert doctors and patients about drug effects that may be dangerous.

Drugs used to treat depression can increase the risk of suicidal thoughts and behaviors. While Contrave is not used to treat depression, it still carries this risk because it contains bupropion as one of its active ingredients. (An active ingredient is what makes a drug work.) Bupropion is an antidepressant.

This risk is rare overall but more likely to occur when you first start treatment and after any dose changes. This risk is also higher in children and young adults ages 24 years and younger. Note that Contrave is only prescribed for use in adults.

Mood and behavior changes can occur from taking Contrave. These changes could be warning signs of suicidal thoughts or behaviors. So it’s important to pay close attention to any changes in mood or behavior, such as:

What might help

If you feel comfortable, talk with your household members about this risk from Contrave. They can then watch for any mood or behavior changes that you may not notice yourself. Your doctor will also monitor you for these symptoms.

Contact your doctor immediately if you have any unexplained mood or behavior changes. They may have you stop taking Contrave. If you have thoughts of harming yourself, call 988, 911, or your local emergency number right away.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Suicide and Crisis Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

Hair loss

Contrave may cause hair loss in some people. This was a rare side effect in the drug’s studies. With hair loss, your hair may become thinner than usual.

What might help

Keep in mind that Contrave is meant to be used together with a low calorie diet. Research has linked calorie restriction with hair loss. Be sure to talk with your doctor about how many calories you should aim to eat each day. Making sure your body receives enough nutrients may help slow or prevent hair loss.

Nausea

In studies, nausea was the most common side effect of Contrave. This side effect may be more noticeable when you first start treatment. It usually eases as your body gets used to the drug.

Keep in mind that Contrave should be taken with a meal. But taking the drug with high fat food can increase the drug’s side effects, such as nausea. If the drug’s side effects are not easing, you may want to check the fat content of the foods you’re consuming with each dose.

What might help

If nausea from Contrave does not go away or becomes severe, talk with your doctor. They can recommend ways to manage this side effect, or they may suggest changes to your dosage or treatment plan.

Constipation

Constipation was a common side effect in studies of Contrave.

What might help

If you have occasional constipation while taking this drug, you might want to try the following:

  • increasing your intake of dietary fiber
  • drinking more water
  • increasing your physical activity
  • taking a gentle laxative, such as senna or MiraLAX

If constipation from Contrave becomes bothersome or severe, talk with your doctor or pharmacist. They can recommend ways to relieve this side effect. Your doctor may also adjust your dosage or treatment plan.

Headache

Headache was a commonly reported side effect in studies of Contrave. This side effect is usually mild and temporary. Though rare, some participants in the drug’s studies had to stop taking Contrave due to headaches.

What might help

Occasional or mild headaches usually go away on their own. You may opt to try an over-the-counter pain reliever, such as Tylenol (acetaminophen). If you have severe headaches while taking Contrave, talk with your doctor. They may recommend a different treatment for you.

Allergic reaction

Like most drugs, Contrave can cause an allergic reaction in some people. Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an antihistamine you swallow, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Contrave, they’ll recommend whether you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Contrave, they may have you switch to a different treatment.

Keeping track of side effects

During your Contrave treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Contrave affects you. They can then use this information to adjust your treatment plan if needed.

This drug comes with several warnings.

Boxed warning: Risk of suicidal thoughts and behaviors

Contrave has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Contrave may increase the risk of suicidal thoughts and behaviors in people ages 24 years or younger. Regardless of whether you are in this age range, your doctor will monitor you closely during Contrave treatment. This risk may be higher when you first start taking the drug and after any dose changes. If you have thoughts of harming yourself, seek medical attention right away.

To learn more, see the “Side effects explained” section.

Other warnings

Contrave may not be right for you if you have certain medical conditions. Other factors may also affect whether this drug is a good treatment option for you. Talk with your doctor about your health history before starting Contrave. Factors to consider include those listed here.

Alcohol and Contrave

Doctors usually recommend avoiding or limiting alcohol use during Contrave treatment. Drinking too much alcohol while taking Contrave could increase the risk of seizures (a serious potential side effect of this drug).

It has been reported that some people who combined alcohol with bupropion, one of the active ingredients in Contrave, experienced the following:

  • decreased alcohol tolerance
  • severe changes in mood or behavior

It’s not known how often these events happened or whether bupropion was the cause in these reports.

If you drink alcohol, talk with your doctor about how much, if any, is safe for you to drink while taking Contrave.

Pregnancy and breastfeeding while taking Contrave

Contrave should not be taken during pregnancy. Contrave is meant to help with weight management in certain adults, along with a low calorie diet and exercise. Weight gain is expected during pregnancy.

If you’re pregnant, talk with your doctor about any concerns you have regarding your weight during pregnancy. If you become pregnant while taking Contrave, tell your doctor. They’ll have you stop taking the drug.

Contrave is not recommended if you’re breastfeeding. The drug passes into breast milk and could cause side effects in a child who is breastfed.

If you’re breastfeeding or planning to do so, tell your doctor before you start taking Contrave. They’ll recommend safe ways to feed your child or suggest a different treatment option for you.

Disclaimer: Healthline 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.