9 Contrave Side Effects You Should Know About

If you’re having trouble managing your weight with diet and exercise alone, your healthcare provider may suggest a weight-loss medication to help. Contrave (naltrexone / bupropion) is an oral medication that combines two active ingredients to reduce your appetite and food cravings. 

Contrave is effective for weight loss when combined with a reduced-calorie diet and regular exercise. But, like any medication, it may cause side effects.

Contrave side effects at a glance

Contrave can cause both mild and serious side effects. Below, there’s an overview of Contrave side effects reported in clinical studies. Keep in mind that this isn’t a complete list of possible side effects. Reach out to your healthcare provider if you have any questions about what to expect while taking Contrave.

Common or mild side effects: 

• Nausea, vomiting, and stomach pain

• Constipation

• Headache

• Dizziness

• Insomnia

• Dry mouth

• Diarrhea

• Anxiety

• Hot flushes and excess sweating

• Fatigue

• Tremors

• Ringing in the ears

• Taste changes

Rare but serious side effects:

• Suicidal thoughts and behaviors

• Mood changes

• Seizures

• Increased blood pressure and heart rate

• Liver problems

• Severe allergic reactions

Let’s take a look at nine possible Contrave side effects in more detail.

1. Nausea and vomiting

In the clinical trials for Contrave, nausea and vomiting were among the most common side effects reported. You’ll start with a low dose of Contrave and slowly increase it over time to help lessen nausea. Any nausea you experience may go away over time as your body gets used to the medication.

In the meantime, try sticking to bland foods and avoiding fried or spicy items. Eating smaller, more frequent meals may also help curb nausea. 

If you vomit after taking Contrave, check with your healthcare provider before taking another dose. You should also let them know if your nausea is severe or doesn’t improve. They may adjust your Contrave dosage or suggest a nausea medication to help you feel more comfortable.

2. Constipation

Constipation is another common Contrave side effect. Staying hydrated and choosing high-fiber foods may help prevent or improve constipation. Regular exercise can also help. Keep in mind that diarrhea is also possible with Contrave, although it’s not as common as constipation.

 If lifestyle changes aren’t enough, check with your provider about trying an over-the-counter (OTC) constipation medication. And be sure to let them know if you have constipation that doesn’t improve or worsens over time. Untreated constipation can lead to other problems, such as hemorrhoids or a blockage in your intestines. 

3. Headache

Contrave can also cause headaches. This side effect may improve as your body adjusts to the medication. But there are steps you can take in the meantime to help.

As with constipation, staying hydrated and getting regular exercise can help with headaches. Be sure you’re also getting enough sleep and minimizing your alcohol intake. If needed, try an OTC pain medication such as acetaminophen (Tylenol).

You should report severe or constant headaches to your healthcare provider. There could be something else causing them that requires treatment. Or you may need a change to your Contrave dosage.

4. Dizziness

Dizziness is another possible Contrave side effect. This may lessen over time as your body adjusts to the medication. But it’s good to be aware of the possibility of dizziness, as it can raise your risk of falls or accidents.

If you’re feeling dizzy, move slowly and carefully to avoid falls. And use caution when driving or doing other activities that require coordination until you know how Contrave affects you.

Keep in mind that dizziness can also be a sign that you’re not eating enough. So be sure to choose nutrient-dense foods. You can also try eating smaller, more frequent meals if your appetite is low. 

If you experience dizziness that’s severe or doesn’t improve with time, talk with your healthcare provider about next steps.

5. Insomnia

While it’s not common, Contrave can cause trouble sleeping (insomnia). Some general tips to help improve sleep include:

• Have a set sleep schedule.

• Keep your bedroom cool and dark.

• Avoid using electronics before bedtime.

• Avoid caffeine, nicotine, and alcohol before you go to sleep.

• Do relaxing activities before bedtime (meditation, calming music, reading).

• Maintain a regular exercise routine.

• Avoid naps during the day.

If it’s OK with your provider, taking OTC sleep medication or supplements such as melatonin may also help. But these sleep aids are only meant for short-term use in most cases. If your insomnia continues, talk to your provider about other options.

6. Dry mouth

Dry mouth can be a bothersome Contrave side effect. It may go away over time, but it can also persist for some people. It’s a good idea to take steps to manage dry mouth, because it can negatively affect your dental health if left unaddressed.

Strategies to relieve dry mouth include sipping on water throughout the day, chewing sugar-free gum, and using OTC saliva-substitute products. And be sure you’re drinking enough fluids. It’s also a good idea to limit caffeine, alcohol, and nicotine, since they can worsen dry mouth symptoms.

It’s good to stay on top of regular teeth cleanings to make sure dry mouth isn’t causing any dental problems. If this side effect worsens or becomes bothersome, talk with your provider about your options.

7. Increased blood pressure and heart rate

Contrave can raise your blood pressure and heart rate while you’re taking it. This side effect is most common in the first 3 months of treatment. But it can happen at any time.

Your provider will likely keep an eye on your blood pressure for the first few months that you’re taking Contrave. They may also ask you to check your blood pressure at home. If your blood pressure reading is high or you’re feeling symptoms such as chest pain or heart palpitations, you should seek medical care right away.

Let your healthcare provider know if you have high blood pressure or other heart problems before taking Contrave. This medication may not be the best option for you.

8. Increased risk of seizures

While rare, Contrave may raise the risk of seizures for some people, especially at high dosages. Seizures are more likely if you have a history of seizures or are taking other medications that can make seizures more likely.

To limit your risk, it’s recommended that you:

• Take no more than four Contrave tablets per day.

• Divide your daily Contrave dosage into two doses.

• Gradually increase your Contrave dosage over time.

• Avoid taking Contrave with high-fat meals. Fat increases how much Contrave you absorb, which can raise medication levels in the body.

If you have a seizure while being treated with Contrave, seek medical care right away. You’ll likely need to stop taking the medication.

9. Suicidal thoughts or behavior

Bupropion, an antidepressant medication, is one of the active ingredients in Contrave. The FDA requires antidepressants to carry a boxed warning, their most serious medication warning, about the potential for an increased risk of suicidal thoughts and behaviors. This increased risk is more likely in people under the age of 25.

Talk to your provider immediately if you or a loved one notices mood changes, worsening depression, or thoughts of suicide while you’re taking Contrave.

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:

Jill Barat, PharmD

Jill Barat, PharmD has nearly 10 years of experience as a pharmacist, including serving as the pharmacist in charge at an independent sterile and non-sterile compounding pharmacy. She also worked as the head of medical content for a telemedicine company.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

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