Contrave: what it treats, how to take it, side effects
Last updated September 3, 2026.
Contrave is a prescription weight-management pill combining naltrexone (an opioid blocker) and bupropion (an antidepressant) in an extended-release tablet. Approved in 2014 for adults with obesity, or overweight with a related condition, alongside diet and activity changes, it works on the brain's hunger and reward circuits. It is a Schedule-free combination, but both ingredients are serious drugs with real warnings.
What does it treat?
Chronic weight management in adults with BMI 30 or higher, or 27 or higher with a weight-related condition like hypertension or type 2 diabetes, used with a reduced-calorie diet and increased activity. It targets appetite and food cravings centrally rather than blocking fat or speeding metabolism.
How do you take it?
The dose ramps over 4 weeks: 1 tablet each morning in week 1, adding an evening tablet in week 2, two morning plus one evening in week 3, then two tablets twice daily from week 4 (each tablet is 8 mg naltrexone/90 mg bupropion). Do not take it with a high-fat meal, which spikes drug levels. At 16 weeks, your doctor checks your weight; if you have not lost enough, the drug is stopped because it is unlikely to work. Swallow tablets whole. Missed dose: skip it; never double up. Blood pressure is monitored because the combination raises it.
Side effects to know
- Common: nausea (the most common, worst during the ramp), constipation, headache, vomiting, dizziness, insomnia, and dry mouth.
- Serious: the boxed warning for suicidal thoughts and behaviors (from bupropion's antidepressant class); seizures (bupropion contraindicates seizure disorders and bulimia); increased blood pressure and heart rate; liver injury; and a crucial practical one: naltrexone blocks opioids, so opioid painkillers will not work on you and using opioids to override the block can kill.
Who should not take it?
No one on opioids, in opioid withdrawal, or likely to need opioid analgesia soon (including planned surgery; the drug stops beforehand). Not with seizure disorders, eating disorders (bulimia/anorexia), uncontrolled hypertension, MAO inhibitors, abrupt alcohol or sedative withdrawal, or pregnancy. Other bupropion products (Wellbutrin, Zyban) cannot stack with it. Liver and kidney impairment change the dose. It is not for children.
When is it an emergency?
Thoughts of self-harm on this medication mean calling or texting 988 (Suicide and Crisis Lifeline, US) right away and contacting your prescriber. Call 911 for a seizure, facial swelling or trouble breathing, or severe chest pain. Signs of liver trouble, dark urine, yellowing eyes, right-upper-belly pain, need same-day attention. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
How much weight do people lose on Contrave?
In the major trials, patients on Contrave with diet and exercise lost roughly 5 to 9% of body weight over a year versus about 1 to 2% on placebo, and about twice as many hit the 5% milestone. It is a meaningful assist, not a transformation, which is why the 16-week checkpoint exists to stop it in non-responders.
Why can't I take opioids on it, and what happens in an emergency?
The naltrexone half blocks opioid receptors, so opioid painkillers lose effect, and trying to override the block with bigger opioid doses risks fatal overdose when the blockade wanes. Carry the information: if you need emergency pain control, doctors use non-opioid routes or manage the blockade deliberately. Planned surgery means stopping Contrave in advance.
What is the boxed warning about?
Bupropion is an antidepressant, and the class carries a boxed warning about increased suicidal thoughts and behaviors in younger patients especially. Contrave is not approved for depression or smoking cessation, but the ingredient brings the warning with it. Mood changes on the drug, especially early, are report-today events.
Is Contrave a controlled substance like phentermine?
No. Neither naltrexone nor bupropion is scheduled, and the combination has no meaningful abuse potential. That is one of its practical advantages over the stimulant-based options, though its warnings, seizure, blood pressure, suicidality, opioids, are their own serious list.
Why do I have to avoid high-fat meals with it?
A high-fat meal sharply increases how much drug hits your bloodstream at once, which spikes side effects. Take it with food, but modest food. This is one of those label details that sounds fussy and is actually load-bearing for tolerability.
What happens after 16 weeks if it is working?
You keep taking it as long as it helps and is tolerated, with periodic blood-pressure checks. Stopping usually means appetite normalizes and weight drifts back, so the plan with your prescriber is long-term: the medication plus the diet and activity pattern it supports, not a 16-week sprint.