Contrave (naltrexone/bupropion) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it to help with weight loss in the following adults:

It’s typically prescribed for long-term weight management in combination with changes in diet and exercise.

Here are some fast facts about Contrave:

  • Active ingredients: naltrexone and bupropion
  • Drug class: opioid antagonist and antidepressant
  • Drug form: extended-release oral tablet, which slowly releases the active ingredients into your body over time

As with other drugs, Contrave can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Contrave, including details about its uses, see this article.

Contrave 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 Contrave in clinical trials:

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

Mild side effects can occur while taking Contrave. This list doesn’t include all possible mild side effects of the drug. To find out more, you can refer to Contrave’s prescribing information.

Mild side effects that have been reported with Contrave include:

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 Contrave and want to tell the FDA about it, visit MedWatch.

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

Contrave may cause serious side effects. The list below may not include all possible serious side effects of the drug. To find out more, you can refer to Contrave’s prescribing information.

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.

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

* Contrave has a boxed warning for this side effect. This is a serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section below.
† An allergic reaction is possible after using Contrave. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

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

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

It’s possible to experience side effects during the first week of treatment with Contrave.

To help prevent side effects, such as seizures, your doctor will first prescribe a low dose of Contrave. Then, they’ll slowly increase your dose each week for 4 weeks.

To learn more about what to expect when you start Contrave, talk with your doctor or pharmacist. If you notice new or worsening symptoms in the first week or during the dose escalation, contact your doctor.

Is Contrave available as a generic? If so, does it cause different side effects than Contrave?

No, there isn’t a generic version of Contrave available. It’s only available as a brand-name drug.

If you have concerns about Contrave’s side effects, talk with your doctor. They can explain which side effects are more common and ways to manage them. They can also recommend other options for weight management.

Does Contrave’s manufacturer have any reviews about side effects?

Yes, Contrave’s manufacturer has patient reviews on its website. In these reviews, people who have taken Contrave discuss their experiences. These experiences may include trying other diet pills and weight management programs. Some of these stories also mention side effects.

Remember, not everyone will have the same side effects. This is because medications don’t always affect different people in the same ways.

If I stop taking Contrave, will I experience certain side effects, such as withdrawal symptoms?

No, withdrawal symptoms weren’t reported in the clinical trials of Contrave. Withdrawal symptoms are side effects that happen after you stop taking a drug your body has become dependent on. Because Contrave isn’t expected to cause physical dependence, withdrawal symptoms aren’t likely after you stop taking it.

However, naltrexone (one of the active drugs in Contrave) can cause withdrawal symptoms in certain people. Naltrexone is an opioid antagonist, which can cause withdrawal symptoms in people taking opioids to treat another condition.

If you have concerns about stopping Contrave or feel it isn’t working, talk with your doctor. Do not stop taking Contrave without talking to your doctor first.

How long does it take for Contrave’s side effects to go away? Does the drug cause any long-term side effects?

Most mild side effects of Contrave are usually 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.

Some serious side effects of Contrave, such as liver damage and angle-closure glaucoma, may be long term. Contact your doctor right away if you experience symptoms of these serious side effects. For more information about symptoms of liver damage and angle-closure glaucoma, see the “Serious side effects” section above.

Learn more about some of the side effects that Contrave may cause, including a boxed warning for the risk of suicidal thoughts and behaviors. To find out how often side effects occurred in clinical trials, see the prescribing information for Contrave.

Risk of suicidal thoughts and behaviors

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

Antidepressants, such as bupropion, can increase the risk of suicidal thoughts and behaviors in people with depression or certain mental health conditions. Bupropion is an active drug in Contrave.

Contrave may increase this risk in children, adolescents, and adults up to 24 years of age. Due to this risk, Contrave isn’t approved for use in people younger than 18 years. No increased risk was reported in adults older than 24 years.

What you can do

In adults who start taking Contrave, doctors will typically monitor you closely for symptoms of suicidal thoughts or behaviors. These can include changes in thoughts, feelings, mood, or behavior. If you notice any of these symptoms, contact your doctor right away.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Click here for more links and local resources.

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Hair loss

Hair loss was reported in Contrave’s clinical trials. It wasn’t common, but it did happen more often in people taking Contrave compared with a placebo. (In these trials, a placebo was a pill without an active ingredient.)

What you can do

If you experience hair loss while taking Contrave, contact your doctor. They can help determine the cause of the hair loss and whether or not Contrave is playing a role. Together, you and your doctor can decide on the best plan to manage hair loss.

Nausea

Nausea was the most common side effect reported in Contrave’s clinical trials. It was also the most common reason people stopped taking Contrave. It’s important to tell your doctor if you experience nausea during treatment. It may be a symptom of hepatitis (liver inflammation) and liver damage.

What you can do

Be sure to tell your doctor about any nausea you experience. They can suggest ways to manage this side effect.

Tips to help relieve nausea include:

  • avoiding strong aromas and smells
  • eating multiple small meals during the day instead of three large meals
  • limiting fatty, fried, spicy, or heavily seasoned foods
  • sipping on liquid or sucking ice chips often

Constipation

Constipation was the second most common side effect reported in clinical trials of Contrave. However, it wasn’t a common reason that people stopped taking the drug.

What you can do

If constipation persists or becomes severe, contact your doctor. They can recommend possible over-the-counter treatments to help relieve constipation, such as a stool softener like Colace (docusate).

Tips to help ease and prevent constipation include:

  • drinking more water
  • increasing the amount of fiber in your diet
  • staying physically active
  • taking a probiotic supplement or eating probiotic foods

Headache

Headache was a common side effect reported in Contrave’s clinical trials. This side effect was also a common reason people decided to stop treatment.

Headaches can be a symptom of other serious side effects of Contrave, including angle-closure glaucoma, high blood pressure, and rapid heart rate.

What you can do

Tell your doctor about headaches that persist or become severe. They can suggest medications to manage this side effect, such as Advil (ibuprofen) and Aleve (naproxen). If your headache is severe and you have other symptoms that concern you, seek medical care right away. In some cases, your doctor may recommend that you stop taking Contrave.

Allergic reaction

As with most drugs, Contrave can cause an allergic reaction in some people. However, it’s not clear whether this side effect occurred 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 Contrave. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

This drug comes with several precautions, including a boxed warning for the risk of suicidal thoughts and behaviors.

Boxed warning: Risk of suicidal thoughts and behaviors

This drug has a boxed warning for the risk of suicidal thoughts and behaviors. This is a serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Contrave. 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:

Activation of mania. Bupropion, an antidepressant, is one of the active ingredients in Contrave. Antidepressants can trigger a manic, mixed, or hypomanic episode in certain people. This risk may be higher in people with bipolar disorder.

Before starting treatment with Contrave, tell your doctor if you have bipolar disorder or any risk factors for it. These factors include a family history of bipolar disorder, or a history of self-harm, suicidal behavior, or depression. Your doctor can discuss whether it’s safe for you to take Contrave.

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

Opioid use. Contrave contains the active drug naltrexone, which is an opioid antagonist. This means it can block the effects of opioids. It can cause withdrawal symptoms in people taking opioids to treat other conditions. (Withdrawal symptoms can occur when you stop taking a drug your body has become dependent on.) Due to this risk, doctors typically won’t prescribe Contrave to people taking an opioid.

If you’re currently taking an opioid treatment, talk with your doctor before starting Contrave. They can recommend other treatments for weight management. Also let your doctor know if you’re prescribed opioids after starting Contrave. They’ll temporarily stop prescribing Contrave until your other condition is treated.

Smoking cessation. Contrave isn’t approved to help people stop smoking. However, bupropion is approved for this use. (Bupropion is one of the active drugs in Contrave.) Some people have experienced serious mental health conditions when attempting to quit smoking while taking bupropion. This includes depression, mania, psychosis, hallucinations, suicidal thoughts, and others. If you have these or other mood or behavior changes, contact your doctor immediately. They’ll likely have you stop taking Contrave.

Type 2 diabetes. Weight loss from Contrave may increase the risk of hypoglycemia (low blood sugar) in people with type 2 diabetes. Specifically, Contrave may cause hypoglycemia if you take insulin or another medication to lower your blood sugar. If you take medication for type 2 diabetes, talk with your doctor before starting Contrave. They can advise how often you should monitor your blood sugar. They can also explain whether Contrave is safe to take with your current diabetes medication.

Alcohol with Contrave

In clinical trials, there weren’t any reported interactions between alcohol and Contrave.

However, drinking alcohol with bupropion can increase some side effects of alcohol. (Bupropion is an active drug in Contrave.) Some of these effects may include nausea or vomiting and dizziness. Drinking alcohol with bupropion can also cause changes in the way you feel, think, or behave. Because of this, your doctor may recommend avoiding or limiting alcohol consumption during Contrave treatment.

If you drink alcohol, ask your doctor how much, if any, is safe to drink while taking Contrave.

Pregnancy and breastfeeding while taking Contrave

Contrave is not safe to take during pregnancy. Weight loss during pregnancy may cause fetal harm. Due to this risk, doctors typically stop treatment with Contrave if you become pregnant.

If you’re pregnant or planning a pregnancy, let your doctor know before starting Contrave. They likely won’t prescribe it. If you become pregnant while taking Contrave, contact your doctor right away. They’ll likely stop prescribing Contrave.

Both of Contrave’s active drugs (naltrexone and bupropion) can pass into breast milk and may cause harm to a child who is breastfed. Due to this risk, breastfeeding during Contrave treatment isn’t recommended.

If you’re breastfeeding or plan to breastfeed, talk with your doctor. They can recommend other treatment options for your condition.

Contrave has some common side effects that are usually mild. However, serious side effects are possible. If you’d like to learn more about Contrave, 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 Contrave. For details about other aspects of Contrave, refer to this article.
  • Dosage. For information about the dosage of Contrave, view this article.
  • Interactions. To find out about Contrave’s interactions, see this article.
  • A look at weight management. For details about weight management, see our exercise and fitness 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.