What are the most common side effects of Contrave?

The label lists nausea, constipation, headache, vomiting, dizziness, insomnia and others among reactions reported in at least 5% of patients. The full frequency table is in the label itself, linked below; any percentage quoted on this page is the label's own figure.

Who should not take it?

The label contraindicates it in these cases: Uncontrolled hypertension; Seizure disorder or a history of seizures; Use of any other bupropion-containing product, such as Wellbutrin, Aplenzin or Zyban; Bulimia or anorexia nervosa, which raise the risk of seizure; Chronic use of an opioid or opiate agonist such as methadone, or a partial agonist such as buprenorphine, or acute opiate withdrawal; Abrupt discontinuation of alcohol, benzodiazepines, barbiturates or antiepileptic drugs; Use with a monoamine oxidase inhibitor, or within 14 days of stopping one; Known allergy to bupropion, naltrexone or any other component.

Do the side effects mean the price is not the issue?

They meet at titration. Most of these reactions are worst in the weeks after a dose increase, and those are also the weeks when some sellers charge a lower starting price. So the months people are most likely to stop are not the months that show what the drug costs. The maintenance price is on the Contrave price page.

← Contrave (naltrexone/bupropion)

Contrave (naltrexone/bupropion) side effects

Contrave's FDA label lists 8 common reactions, 10 serious warnings and 8 contraindications, plus a boxed warning. All of them are below in the label's own order; any percentage is the label's own figure, and nothing here is a recommendation.

No clinician has reviewed this page. Label and trial statements are quoted from the FDA label or the trial cited beside them. General guidance is marked as such, and every price carries the date it was verified. That is sourcing, not medical review. What we do and do not check · Who checked the price

Last updated 2025-11-17 — the version of the FDA label this page quotes. Read and dated by Alex Seot.

What are the side effects of Contrave?

The FDA label for Contrave lists nausea, constipation, headache, vomiting and dizziness among the reactions reported in at least 5% of patients. It carries a boxed warning, the strongest the FDA issues: Bupropion raises the risk of suicidal thoughts and behavior in children, adolescents and young adults. The label's serious warnings include suicidal thoughts and behavior; neuropsychiatric events reported with bupropion used for smoking cessation; seizures; and opioid overdose and precipitated withdrawal. It is contraindicated in 8 cases, among them uncontrolled hypertension, meaning the label says not to prescribe it at all. Every line above is quoted from FDA prescribing information for CONTRAVE rather than summarized from a secondary source, because a side-effect list paraphrased twice stops being the label. That label version was published 2025-11-17. Frequencies are not repeated here second-hand: the percentage table lives in the label itself, which is linked on the page.

Boxed warning — the strongest warning the FDA issues

Bupropion raises the risk of suicidal thoughts and behavior in children, adolescents and young adults. The label carries that as a boxed warning and tells prescribers to watch for mood changes, particularly in the first months and after any dose change.

Common, and usually manageable

Reactions the label reports in at least 5% of patients.

nausea
constipation
headache
vomiting
dizziness
insomnia
dry mouth
diarrhea

This is not a GLP-1: it is naltrexone plus bupropion, and its boxed warning and main serious risks concern mood, seizures, opioid use and blood pressure. Its most common side effect is still nausea: in the trials 24% stopped because of an adverse event, against 12% on placebo, and nausea was the most common reason, at 6.3%. Anyone on long-term opioid treatment, including buprenorphine for addiction, cannot take it; for a short course of opioids it is paused, and lower opioid doses may be needed.

Serious, and worth knowing before you start

Suicidal thoughts and behavior: bupropion belongs to an antidepressant class, and the boxed warning applies. The label says to monitor for clinical worsening, especially in the first months and after any dose change
Neuropsychiatric events reported with bupropion used for smoking cessation, which Contrave is not approved for: mood changes, psychosis, hallucinations, paranoia, aggression and suicidal ideation. Stop and call the prescriber if agitation, depressed mood or unusual changes in behavior appear
Seizures: the risk is dose-related, and after a seizure the label says to stop and not restart. No more than two tablets at a time, twice daily, escalated gradually, and not with a high-fat meal
Opioid overdose and precipitated withdrawal: naltrexone blocks opioids, so trying to overcome the block with large doses can be fatal. Anyone on chronic opioids cannot take it, and it is stopped before any planned opioid treatment
Increase in blood pressure and heart rate: the label says to measure both before starting and at regular intervals, and not to give it in uncontrolled hypertension
Allergic reactions: anaphylaxis, angioedema and urticaria, with rare Stevens-Johnson syndrome and erythema multiforme reported for bupropion, and delayed reactions resembling serum sickness
Hepatotoxicity: hepatitis and clinically significant liver dysfunction with naltrexone. Stop if symptoms of acute hepatitis appear
Activation of mania: antidepressant treatment can precipitate a manic, mixed or hypomanic episode. The label says to screen for bipolar disorder and its risk factors before starting
Angle-closure glaucoma: pupil dilation from bupropion can trigger an attack in anyone with anatomically narrow angles and no patent iridectomy
Hypoglycemia in type 2 diabetes treated with insulin or sulfonylureas, because weight loss lowers glucose. The label says to measure blood glucose before and during treatment and to consider lowering the antidiabetic doses

Who cannot take it

Uncontrolled hypertension
Seizure disorder or a history of seizures
Use of any other bupropion-containing product, such as Wellbutrin, Aplenzin or Zyban
Bulimia or anorexia nervosa, which raise the risk of seizure
Chronic use of an opioid or opiate agonist such as methadone, or a partial agonist such as buprenorphine, or acute opiate withdrawal
Abrupt discontinuation of alcohol, benzodiazepines, barbiturates or antiepileptic drugs
Use with a monoamine oxidase inhibitor, or within 14 days of stopping one
Known allergy to bupropion, naltrexone or any other component

Each of these, on its own

What the label says, why it happens, how it tracks the dose schedule and the point at which it stops being ordinary.

What it costs Dosage schedule

Questions

What are the most common side effects of Contrave?: The label lists nausea, constipation, headache, vomiting, dizziness, insomnia and others among reactions reported in at least 5% of patients. The full frequency table is in the label itself, linked below; any percentage quoted on this page is the label's own figure.
Who should not take it?: The label contraindicates it in these cases: Uncontrolled hypertension; Seizure disorder or a history of seizures; Use of any other bupropion-containing product, such as Wellbutrin, Aplenzin or Zyban; Bulimia or anorexia nervosa, which raise the risk of seizure; Chronic use of an opioid or opiate agonist such as methadone, or a partial agonist such as buprenorphine, or acute opiate withdrawal; Abrupt discontinuation of alcohol, benzodiazepines, barbiturates or antiepileptic drugs; Use with a monoamine oxidase inhibitor, or within 14 days of stopping one; Known allergy to bupropion, naltrexone or any other component.
Do the side effects mean the price is not the issue?: They meet at titration. Most of these reactions are worst in the weeks after a dose increase, and those are also the weeks when some sellers charge a lower starting price. So the months people are most likely to stop are not the months that show what the drug costs. The maintenance price is on the Contrave price page.

Source: FDA prescribing information for CONTRAVE, the version published 2025-11-17. Information only, not medical advice: a side effect you are having is a conversation with your prescriber, not with a comparison site.