A pill bottle with blue Contrave pills spilling out on a red background.

10 Contrave Side Effects—And How to Deal With Them

There’s a big difference between mild and severe ones—here’s how to handle each type of symptom.

30-Second Takeaway

  • Contrave is a weight loss drug often prescribed to those who have a BMI score within the obese range (30+). If you’re overweight, or have a BMI score of 27, and have a chronic health condition, you may also be eligible for a prescription.
  • The most common side effects of Contrave are mild, but serious side effects—such as raised blood pressure—can occur.
  • If you let serious side effects linger, they can lead to further health complications, which is why it’s so important to do regular check-ins with your physician.

Prescription medications like Contrave can help you lose weight more effectively. But like any drug, there are a few possible Contrave side effects to know about before talking to your doctor about starting the drug. 

Contrave is a weight loss drug designed for people who are overweight and have a weight-related medical condition such as high blood pressure or type 2 diabetes, or are considered obese by their BMI score (1)

“Contrave combines two drugs, naltrexone and bupropion, which work in the brain to reduce appetite and food cravings,“ says internal medicine physician Dalia Alatassi, M.D. However, with these benefits comes the possibility of side effects. 

Ahead, Alatassi and gastroenterologist Steven Batash, M.D., identify potential Contrave side effects—and what to do about them if you start experiencing them.

About the Experts 

Diala Alatassi, M.D.  is a physician who is double board-certified in obesity and internal medicine and works with the Endeavor Health Medical Group.

Steven Batash, M.D.  is a board-certified gastroenterologist and leading physician at the Batash Endoscopic Weight Loss Center.

How Can Contrave Help You Lose Weight? 

Doctors don’t exactly know how Contrave causes weight loss. But they do know its active ingredients, naltrexone and bupropion, work in the brain to decrease the pleasure you get from food while suppressing appetite, Batash suggests (1).

How to use Contrave

If it’s prescribed, you’ll take Contrave by mouth. For the first week, you will take one tablet every morning and by the second week, you will take it twice a day (once in the morning and once in the evening). The dose is increased each week until you reach two tablets twice a day. You should swallow the tablets whole, don’t crush, cut, or chew to avoid releasing the drug all at once into your body, which can increase your risk of side effects. 

“Like most medications, Contrave should be taken with food or water,” says Batash, noting this simple step may help prevent mild side effects like nausea.

Contrave is one part of a holistic weight management plan—by itself, it’s not the golden ticket to sustainable weight loss, Batash says. While taking it, you will also need to eat fewer calories and exercise more, he adds. 

Side Effects to Watch Out For

As is the case with most medications, Contrave can cause side effects that range from mild to serious—and they vary from person to person.

“Some people may find that side effects become less bothersome over time as their bodies adjust to the medication, while others may continue to experience significant discomfort,” Alatassi says.

Nausea and vomiting

Nausea is the most common side effect of Contrave. While it’s usually tame for most people, others can find it particularly annoying, Alatassi notes. 

To reduce the queasiness, you can suck on ice chips, sip ginger tea, or enjoy a ginger chew or two. If those tricks don’t work, your physician may be able to prescribe anti-nausea medication (2).


If you feel a headache coming on while taking Contrave, it’s not unheard of. Headaches are a known side effect of the drug, Batash notes. If it’s mild, it will probably subside on its own. If a headache lingers, an over-the-counter pain reliever such as Advil or Tylenol should do the trick. 

Of course, if your headache is severe, worsens over time, or just won’t go away, reach out to your doctor about potentially switching to a different drug. Sometimes Contrave isn’t the right weight loss drug for you—and that’s OK, there are other prescription weight loss drugs that may work for you.


Feeling backed up when starting Contrave isn’t unusual. One powerful way to get ahead of constipation is staying hydrated. Experts say drinking about 3.7 liters (15.5 cups) of water a day if you’re a man (man is used to refer to those assigned male at birth) and 2.7 liters (11.5 cups) a day if you’re a woman (which describes those assigned female at birth) can help with this (3)

Regular exercise and tweaking your diet can help you stay regular, as well, notes Batash. “Increasing fiber also helps with constipation,” he says. Fiber-rich foods include beans, whole grains, fruits and vegetables.  

Dry mouth

Contrave can leave your mouth feeling as dry as a desert. It may help to stay hydrated, drink electrolytes, suck on ice cubes, or chew sugar-free gum (4).  

Serious Contrave Side Effects 

Unfortunately, not all side effects can be treated with home remedies and over-the-counter meds (2). The following serious Contrave side effects can cause major health complications, it’s a good idea to reach out to your doctor immediately if you notice any of them.


If you usually sleep well at night but suddenly have difficulty falling asleep—and staying asleep—while taking Contrave, this could be a sign that the drug isn’t the right fit for you (2). Without enough sleep, it can be hard to accomplish daily tasks such as chores and thinking critically at work. Sleep problems can also make you feel fatigued, increase your risk of chronic health conditions, and even affect your mental well-being (5).

Batash recommends establishing a sleep hygiene routine to see if that improves your ability to catch some quality Zz’s. But if that doesn’t help, you may need to stop Contrave completely—but only after speaking with your doctor.  

Increased blood pressure and heart rate

“Contrave can potentially increase blood pressure, which may be a concern for individuals with hypertension or other cardiovascular conditions,” Alatassi says. 

High blood pressure can damage your blood vessels and raise your risk of stroke and heart disease (6). The good news is that your physician will regularly monitor your blood pressure and heart rate as you’re taking the drug. 

If you experience signs of increasing blood pressure—chest pain, a rapid heart rate, or feel lightheaded and dizzy—mention them to your doctor. You can also have high blood pressure with zero symptoms, which is why regular check-ins with your provider are important. 


Another serious side effect of Contrave is angle-closure glaucoma, a condition which can severely affect your eye health. Symptoms include severe headaches, blurry vision, eye pain, and seeing rings around lights. Angle-closure glaucoma is a medical emergency; if it isn’t treated quickly, it could leave you permanently blind (7). 

Liver damage or hepatitis (liver inflammation)

The drugs that make up Contrave—naltrexone and bupropion—can hurt your liver. Red flags to watch out for include abdominal pain, jaundice, dark urine, and feeling tired all the time (8). Fortunately, this side effect is quite uncommon, happening to less than 1 percent of people, though people have had liver injury from using the individual drugs in Contrave (9).


Contrave can also cause seizures. The chances of having seizures while taking Contrave are higher if you have certain medical conditions such as epilepsy, head injury or stroke or if you take other medications that contain either naltrexone or bupropion (such as Wellbutrin) at the same time (10).

Changes in behavior or suicidal thoughts

When starting any new drug, watch for notable changes in your mood (anxiety, irritability, impulsivity) or behavioral changes—such as unusually high levels of energy, anger or aggression—especially if you’ve dealt with depression, bipolar disorder, or manic episodes in the past (2). 

What To Know About Contrave

Frequently Asked Questions

1. What should you do if Contrave side effects don’t improve?

If side effects don’t improve after a few days, your doctor may be able to treat them easily. On the other hand, they could be a sign of more serious underlying conditions that need urgent attention. 

Sometimes, the only way to truly know if something bigger is going on in your body is by getting them checked out. Stay on top of your follow-up visits with your doctor, and always keep an open dialogue with them. 

And be sure to keep them in the loop on any mild side effects you’re dealing with too, because they may have a quick solution for you.

2. Who shouldn’t take Contrave?

You shouldn’t take Contrave if you are younger than 18, pregnant or breastfeeding, allergic to any of its ingredients, taking certain medications such as opioids or antidepressants, or experiencing any of the serious side effects above (2).

  1. Matthew M. Sherman, et al. (2016) Naltrexone/Bupropion ER (Contrave) 
  2. Contrave (n.d.) FAQs – CONTRAVE® (naltrexone HCl/bupropion HCl).
  3. National Academies of Sciences, Engineering and Medicine. (2005) Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate | The National Academies Press
  4. Johns Hopkins Medicine. (n.d.) Dry Mouth Remedies: 14 to Try
  5. National Heart, Lung and Blood Institute. (n.d.) What are Sleep Deprivation and Deficiency?
  6. WHO. (n.d.) Hypertension.
  7. Simone Nuble et al. (2021) Acute Closed-Angle Glaucoma—An Ophthalmological Emergency – PMC
  8. United Kingdom National Health Service. (n.d.) Liver disease
  9. National Institute of Diabetes and Digestive and Kidney Diseases (2020) Naltrexone-Bupropion – LiverTox 
  10. Medsafe. (n.d.) Consumer Medicine Information (CMI) summary: 1. Why am I using Contrave?