Short answer: In the label's placebo-controlled trials, the most common Contrave side effects were nausea (32.5% vs 6.7% on placebo), constipation (19.2% vs 7.2%), headache (17.6% vs 10.4%), vomiting (10.7% vs 2.9%), dizziness (9.9% vs 3.4%), insomnia, dry mouth and diarrhea. 24% stopped because of side effects vs 12% on placebo. Contrave has a boxed warning about suicidal thoughts and behaviors.
What Contrave is approved for: Contrave is approved, with a reduced-calorie diet and more physical activity, to reduce excess body weight and keep it off long term in adults with obesity, or with overweight and at least one weight-related condition (section 1). The label says its effect on heart disease and death has not been established, and it must not be used with other bupropion products.
Source
CONTRAVE (naltrexone hydrochloride and bupropion hydrochloride) extended-release tablets, prescribing information and Medication Guide. Currax Pharmaceuticals. DailyMed, version published November 17, 2025. DailyMed setid 485ff360-32c8-11df-928b-0002a5d5c51b
WARNING: SUICIDAL THOUGHTS AND BEHAVIORS
Contrave is not approved to treat depression or other psychiatric disorders, but it contains bupropion, the same active ingredient as some antidepressants (such as Wellbutrin and Aplenzin). In short-term trials, antidepressants increased the risk of suicidal thoughts and behavior in children, teens and young adults; there was no increase in people over 24, and a reduction in people 65 and older. People of all ages starting Contrave are watched closely for worsening mood and new suicidal thoughts or behaviors, and families and caregivers are told to watch closely and keep in touch with the prescriber. Contrave is not approved for use in children.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Contrave.
| Adverse reaction | CONTRAVE 32 mg/360 mg N=2545 % | Placebo N=1515 % |
|---|---|---|
| Nausea | 32.5 | 6.7 |
| Constipation | 19.2 | 7.2 |
| Headache | 17.6 | 10.4 |
| Vomiting | 10.7 | 2.9 |
| Dizziness | 9.9 | 3.4 |
| Insomnia | 9.2 | 5.9 |
| Dry mouth | 8.1 | 2.3 |
| Diarrhea | 7.1 | 5.2 |
| Anxiety | 4.2 | 2.8 |
| Hot flush | 4.2 | 1.2 |
| Fatigue | 4.0 | 3.4 |
| Tremor | 4.0 | 0.7 |
| Upper abdominal pain | 3.5 | 1.3 |
| Viral gastroenteritis | 3.5 | 2.6 |
| Influenza | 3.4 | 3.2 |
| Tinnitus | 3.3 | 0.6 |
| Urinary tract infection | 3.3 | 2.8 |
| Hypertension | 3.2 | 2.2 |
| Abdominal pain | 2.8 | 1.4 |
| Hyperhidrosis | 2.6 | 0.6 |
| Irritability | 2.6 | 1.8 |
| Blood pressure increased | 2.4 | 1.5 |
| Dysgeusia | 2.4 | 0.7 |
| Rash | 2.4 | 2.0 |
| Muscle strain | 2.2 | 1.7 |
| Palpitations | 2.1 | 0.9 |
Five placebo-controlled trials of up to 56 weeks in 4,754 adults with overweight or obesity; 2,545 took Contrave 32 mg/360 mg a day for a mean of 36 weeks. Mean age 46, 82% women. Stopping because of side effects: 24% on Contrave vs 12% on placebo, most often for nausea (6.3%), headache (1.7%) and vomiting (1.1%).
Psychiatric and sleep reactions in the one-year trials: 22.2% on Contrave vs 15.5% on placebo, made up of sleep disorders (13.8% vs 8.4%), depression (6.3% vs 5.9%) and anxiety (6.1% vs 4.4%). In the small group aged 65 and older, it was 28.6% vs 6.3%.
Attention, dizziness and fainting reactions: 15.0% vs 5.5% on placebo. Dizziness alone was 10.4% vs 3.4%, and led 0.9% to stop (vs 0.3%).
Blood pressure and heart rate: blood-pressure-related reactions in 6.3% vs 4.2% on placebo (12.0% vs 6.5% in a trial of people with diabetes). In the first 12 weeks, blood pressure ran 1.8 to 2.4 mmHg (systolic) and 1.7 to 2.1 mmHg (diastolic) higher than placebo, and heart rate about 2 beats per minute higher.
Seizures occurred in about 0.1% of people on Contrave vs 0% on placebo.
In the obesity trials of up to 56 weeks, there were no suicides or suicide attempts on Contrave. Suicidal thoughts were reported by 1 of 3,239 people on Contrave (0.03%) and 3 of 1,515 on placebo (0.20%).
Serum creatinine rose more on Contrave (mean 0.07 mg/dL vs 0.01 mg/dL on placebo); rises above normal and at least 50% over baseline were seen in 0.6% vs 0.1%.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Suicidal thoughts and behavior. The boxed warning risk. Everyone on Contrave is watched for worsening depression, suicidal thoughts and unusual changes in behavior, especially in the first few months and after dose changes. Symptoms such as anxiety, agitation, panic, insomnia, irritability, aggression or restlessness may come before these.
Mood and behavior changes. Serious mood and behavior changes, including depression, mania, psychosis, hallucinations, aggression and suicidal thoughts, have been reported in people taking bupropion to quit smoking. If agitation, depressed mood or unusual changes in behavior or thinking appear, Contrave is stopped and a healthcare provider contacted.
Seizures. Bupropion can cause seizures, and the risk rises with dose. Contrave is not used in people with a seizure disorder, an eating disorder such as anorexia or bulimia, or who are suddenly stopping alcohol, benzodiazepines, barbiturates or seizure medicines. If a seizure happens, Contrave is stopped and not restarted.
Opioids. Naltrexone blocks opioids. Contrave is not used with long-term opioid use. Trying to override the block with large opioid doses can cause fatal overdose, and people may be more sensitive to opioids after stopping Contrave. People need to be opioid-free for 7 to 10 days (up to two weeks after buprenorphine or methadone) before starting.
Blood pressure and heart rate. Contrave can raise blood pressure and resting heart rate. These are checked before starting and regularly after, and Contrave is not used with uncontrolled high blood pressure.
Allergic reactions. Serious allergic reactions, and rarely Stevens-Johnson syndrome, have been reported with bupropion. Joint and muscle aches with fever and rash can also happen as a delayed reaction.
Liver injury. Hepatitis and significant liver problems have been seen with naltrexone. If signs of acute hepatitis appear, Contrave is stopped.
Mania. Bupropion can trigger mania or hypomania, especially in people with bipolar disorder or risk factors for it. People are screened for bipolar history before starting.
Angle-closure glaucoma. Pupil widening from bupropion may trigger an angle-closure glaucoma attack in people with narrow eye angles who have not had an iridectomy.
Low blood sugar in type 2 diabetes. Weight loss may raise the risk of low blood sugar in people on insulin or a sulfonylurea. Blood sugar is checked before and during treatment, and lowering those medicines may be considered.
From the Medication Guide that comes with Contrave:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.