2026-07-04 · medications, contrave, naltrexone, bupropion, obesity medicine, reward-driven eating, prescription · 18 min read

How much weight loss should I actually expect on Contrave?

In the pivotal 56-week COR-I trial (Greenway 2010, The Lancet), adults on Contrave 32/360 mg lost a mean of 6.1% total body weight versus 1.3% on placebo — a placebo-adjusted difference of roughly 5%. The COR-II confirmatory trial (Apovian 2013, Obesity) reproduced the number at 6.4% vs 1.2%. When Contrave is layered onto an intensive behavioural-modification program (COR-BMOD, Wadden 2011, Obesity), the number rises to a mean 9.3% versus 5.1% for behavioural therapy alone. In adults with type 2 diabetes (COR-Diabetes, Hollander 2013, Diabetes Care), the mean was 5.0% versus 1.8%, with a 0.6% A1c reduction. Honest positioning: Contrave produces roughly half the weight loss of semaglutide 2.4 mg (Wilding 2021 STEP-1 in NEJM: ~15% at 68 weeks) and roughly one-third of tirzepatide 15 mg (Jastreboff 2022 SURMOUNT-1 in NEJM: ~21% at 72 weeks). Real-world discontinuation is high — Yeh 2016 in JAMA Internal Medicine reported about 65% of Contrave starters had stopped by 12 months, the highest of the FDA-approved options at the time — so the effect you actually keep depends heavily on tolerating the drug through the first 6 to 12 weeks.

Who is Contrave a good fit for?

Contrave earns a place for three distinct groups. First, adults who cannot use a GLP-1 medication — because of cost, insurance, injection aversion, personal or family history of medullary thyroid cancer or MEN2, or a history of severe GI side effects. Second, adults whose eating pattern is predominantly reward-driven — snacking on highly palatable foods, evening grazing, cravings that dominate over hunger — because the mesolimbic dopamine/reward-circuit modulation from combined naltrexone and bupropion targets that pathway more directly than a GLP-1 does (Billes 2014, Pharmacological Research; Ornellas 2011, Journal of Medicinal Chemistry). Third, adults with comorbid depression or tobacco dependence, where bupropion is independently useful — bupropion is FDA-approved for major depressive disorder and for smoking cessation, so Contrave can serve double duty in the right patient (APA 2016 MDD guideline; bupropion prescribing information). Not a fit if you take chronic opioids, have a seizure history, have a current or prior eating disorder (bulimia or anorexia), have uncontrolled hypertension, or are within 14 days of an MAOI.

What is the boxed warning on Contrave?

Contrave carries the same boxed warning that bupropion carries: an increased risk of suicidal thoughts and behaviours in children, adolescents, and young adults, and neuropsychiatric symptoms (agitation, hostility, depression, mood changes) in adults taking bupropion for smoking cessation and, by extension, in Contrave (bupropion prescribing information; FDA 2014 Contrave approval labelling). The absolute risk is small and the boxed warning does not mean the drug causes suicide in most people — it means the risk is high enough to warrant baseline mood screening, a clear plan for any new or worsening depression or suicidal ideation, and immediate discontinuation and clinician contact if either appears. If you or someone you know is in mental-health crisis, call or text 988 (the 988 Suicide and Crisis Lifeline in the US) or go to the nearest emergency department. Do not stop Contrave abruptly without notifying your prescriber — bupropion has a seizure risk that can worsen with certain discontinuation patterns.

Why is Contrave contraindicated with chronic opioids?

Because naltrexone is a competitive opioid antagonist. If you are on chronic opioids (for pain, for post-surgical recovery, or as medication for opioid use disorder such as methadone or buprenorphine), starting Contrave does two dangerous things at once: it blocks the analgesic effect of the opioid so pain returns, and it precipitates opioid withdrawal — often severe and requiring emergency care (naltrexone prescribing information; FDA 2014 Contrave labelling). The rule is simple: if you are on any daily opioid, Contrave is contraindicated until you have completed an opioid taper and been opioid-free long enough for a supervised naltrexone challenge (typically 7 to 10 days off short-acting opioids and 10 to 14 days off methadone or buprenorphine). If an emergency requires opioid analgesia while you are on Contrave, tell the emergency team you are on naltrexone — higher-than-usual doses may be needed, monitoring is more intensive, and the priority is safe analgesia rather than continuing Contrave through the acute event.

How is Contrave dosed and titrated?

The standard titration is over four weeks, always taken with a low-fat meal (a high-fat meal raises bupropion exposure enough to increase seizure risk per the prescribing information). Week 1: one tablet (naltrexone 8 mg / bupropion 90 mg) in the morning. Week 2: one tablet in the morning and one in the evening. Week 3: two tablets in the morning and one in the evening. Week 4 and beyond: two tablets in the morning and two in the evening, for a target daily dose of 32 mg naltrexone and 360 mg bupropion. The FDA stop rule (FDA 2014 labelling): if you have not lost at least 5% of your baseline body weight by week 16, discontinue Contrave — continued use beyond that point is unlikely to produce meaningful weight loss and unnecessarily exposes you to the drug's side-effect profile. Titrate slowly; the most common reasons for early discontinuation in the COR trials (Aronne 2013, Current Medical Research and Opinion) were nausea, headache, and insomnia — all of which are more manageable with slow titration.

What are the most common side effects?

In the COR-I and COR-II pivotal trials (Greenway 2010; Apovian 2013), the most common adverse events on Contrave 32/360 mg versus placebo were nausea (~30% vs 5%), constipation (~19% vs 7%), headache (~18% vs 10%), vomiting (~10% vs 3%), dizziness (~10% vs 3%), insomnia (~9% vs 5%), and dry mouth (~8% vs 2%). Nausea is the most common reason for early discontinuation and usually attenuates over 4 to 8 weeks; taking Contrave with a low-fat meal (not with a high-fat meal) helps. Bupropion can raise systolic blood pressure by roughly 1 to 2 mmHg on average — a small mean effect that matters more in people with borderline or uncontrolled hypertension, which is why baseline and follow-up BP measurement is standard. Seizure risk at approved doses is roughly 0.1% and is higher in people with eating disorders, alcohol or benzodiazepine withdrawal, and abrupt discontinuation of certain other drugs — all of which are screening questions before prescribing.

Can I take Contrave with a GLP-1 medication like Wegovy or Zepbound?

There is no direct pharmacokinetic interaction between Contrave and semaglutide or tirzepatide, and the mechanisms are complementary (dopaminergic/reward-circuit vs GLP-1/incretin), so combination use is biologically reasonable and is sometimes prescribed off-label. In practice, most clinicians pick one drug and optimize it before considering combination, because the GI burden of the GLP-1 stacked on top of the nausea burden of Contrave often makes both harder to tolerate, and the added cost is substantial. If you are already on a GLP-1 and asking whether to switch to Contrave, the honest framing is that you will trade about half the weight loss for lower monthly cost, oral rather than injection dosing, no medullary-thyroid concern, and a different side-effect profile — but you will add a seizure precaution, an opioid-antagonism liability, and a boxed suicidal-behaviour warning. Talk through the trade-offs with your prescriber; see prescription weight loss medications for the broader comparison.

Can I take Contrave with an antidepressant?

It depends on the antidepressant. Do not take Contrave with another bupropion product (Wellbutrin, Zyban, generic bupropion) — the doses would stack and seizure risk would rise sharply. Do not take Contrave within 14 days of an MAOI (phenelzine, tranylcypromine, isocarboxazid, selegiline, linezolid) — the interaction can produce hypertensive crisis. SSRIs and SNRIs are commonly co-prescribed with Contrave for comorbid depression or anxiety, but bupropion inhibits CYP2D6 and can raise levels of some SSRIs (particularly paroxetine and fluoxetine metabolites) and TCAs, and serotonergic drugs stacked with bupropion can lower seizure threshold — so dose adjustments and closer monitoring are appropriate. If you have comorbid depression and are considering Contrave, one reasonable strategy is to have your prescriber use bupropion (as part of Contrave) as the antidepressant rather than stacking a separate agent — bupropion is independently effective for major depressive disorder (APA 2016 MDD guideline). See antidepressants and weight changes for the broader picture.

Contrave (Naltrexone-Bupropion) for Weight Loss: What It Does, Who It Fits, and Where It Falls Short

Quick stats

• Placebo-adjusted weight loss at 56 weeks (Greenway 2010 COR-I, The Lancet): mean 6.1% on Contrave 32/360 mg vs 1.3% on placebo — a difference of roughly 5%.
• With intensive behavioural modification (Wadden 2011 COR-BMOD, Obesity): mean 9.3% on Contrave + BMOD vs 5.1% on BMOD alone.
• FDA-approved indication (FDA 2014): BMI ≥30, or BMI ≥27 with at least one weight-related comorbidity (hypertension, dyslipidemia, type 2 diabetes).
• Seizure incidence at approved dose (bupropion prescribing information): roughly 0.1% — higher with eating disorders, alcohol or benzodiazepine withdrawal, or abrupt discontinuation of certain drugs.
• Boxed warning inherited from bupropion: suicidal thoughts and behaviour in children, adolescents, and young adults; neuropsychiatric symptoms — if in mental-health crisis, call or text 988.
• Opioid analgesia interaction (naltrexone prescribing information): Contrave blocks opioid analgesia and precipitates withdrawal in opioid-dependent patients — chronic opioid use is a contraindication.
• Emergency red flags: new-onset seizure — call 911; severe hypertensive emergency — call 911; suspected overdose — call poison control at 1-800-222-1222.

The honest picture, in one paragraph

Contrave produces roughly 5–6% placebo-adjusted weight loss on average over 56 weeks (Greenway 2010 COR-I; Apovian 2013 COR-II) — clinically useful and reproducible, but roughly half of semaglutide 2.4 mg (~15% at 68 weeks in Wilding 2021 STEP-1, NEJM) and roughly one-third of tirzepatide 15 mg (~21% at 72 weeks in Jastreboff 2022 SURMOUNT-1, NEJM). It works through a distinct mechanism — bupropion drives POMC neuron activation and dopaminergic reward-circuit modulation, and naltrexone blocks the auto-inhibitory β-endorphin feedback loop that would otherwise damp that activation (Ornellas 2011, Journal of Medicinal Chemistry; Billes 2014, Pharmacological Research) — so it targets reward-driven and palatability-driven eating in a way GLP-1s do not. It earns a place for adults who cannot use a GLP-1, adults whose eating pattern is dominated by cravings and reward rather than hunger, and adults with comorbid depression or tobacco dependence where bupropion is independently useful. It is not appropriate for anyone on chronic opioids (naltrexone blocks analgesia and precipitates withdrawal), anyone with a seizure history, a current or prior eating disorder, or uncontrolled hypertension, and it must not be started within 14 days of an MAOI. Contrave carries a boxed warning for suicidal thoughts and behaviour inherited from bupropion, a real seizure risk at the approved dose (~0.1%), and — per the FDA label — must be discontinued if less than 5% weight loss has been achieved by week 16.

How Contrave is dosed

Contrave is an oral fixed-dose combination of naltrexone SR 8 mg and bupropion SR 90 mg per tablet. The standard titration is over four weeks, always taken with a low-fat meal — a high-fat meal raises bupropion exposure enough to increase seizure risk (Contrave prescribing information). Do not cut, crush, or chew the tablets — the sustained-release matrix is what keeps peak bupropion levels below the seizure threshold.

FDA stop rule (FDA 2014 labelling): if you have not lost at least 5% of baseline body weight by week 16 on the target dose, discontinue Contrave. Continued use beyond that point is unlikely to produce meaningful weight loss and unnecessarily exposes you to the boxed-warning and seizure-risk profile.

Why Contrave works (and does not) for weight

Four mechanistic threads explain the modest but real weight loss seen in COR-I, COR-II, COR-BMOD, and COR-Diabetes. None describe a direct calorie-burning effect — they describe why the same eating pattern produces different food-seeking behaviour when both drugs are on board.

1. POMC neuron activation (bupropion)

Bupropion inhibits presynaptic reuptake of dopamine and norepinephrine and, in the arcuate nucleus of the hypothalamus, activates pro-opiomelanocortin (POMC) neurons that release α-melanocyte-stimulating hormone (α-MSH) and drive satiety (Ornellas 2011, Journal of Medicinal Chemistry; Billes 2014, Pharmacological Research). This is the anorectic arm of Contrave’s mechanism and it overlaps in effect — but not in molecular target — with the appetite-reducing effect of a GLP-1 receptor agonist.

2. β-endorphin auto-inhibitory blockade (naltrexone)

The problem with using bupropion alone for weight loss is that POMC neurons also release β-endorphin, and β-endorphin acts on the same POMC neurons through µ-opioid receptors to produce auto-inhibitory feedback — the very activation that reduces appetite also switches on a self-limiting brake. Naltrexone is a competitive µ-opioid receptor antagonist. By blocking that brake, naltrexone extends and amplifies POMC activation (Ornellas 2011; Billes 2014). This is why the combination outperforms either drug alone at every dose tested (Greenway 2010 COR-I).

3. Mesolimbic dopamine and reward-circuit modulation

Both drugs modulate the mesolimbic dopaminergic reward pathway that governs the palatability and hedonic value of food — the pathway that determines how much a highly palatable food “pulls” the eater beyond hunger. Bupropion increases synaptic dopamine in the nucleus accumbens; naltrexone blocks endogenous opioid signalling that contributes to reward. The clinical consequence is that Contrave reduces reward-driven and palatability-driven eating — snacking, evening grazing, craving-dominant food-seeking — more directly than a GLP-1 does (Billes 2014). This is the strongest population-specific benefit and is the mechanistic reason Contrave earns its niche in reward-driven eating patterns.

4. What Contrave is not

Contrave is not a GLP-1 — the weight loss is roughly half the size of semaglutide 2.4 mg and one-third of tirzepatide 15 mg. Contrave is not a metabolic drug in the way GLP-1s are — the A1c effect in Hollander 2013 COR-Diabetes was a modest 0.6% and there are no cardiovascular outcome data supporting mortality or MACE reduction (the Nissen 2016 LIGHT trial was terminated early after unblinded interim data were released and did not provide the definitive CV verdict the FDA had required at approval). And Contrave is not a substitute for a calorie deficit — the COR-BMOD result (Wadden 2011) is a reminder that Contrave layered on intensive behavioural modification produces substantially better outcomes than Contrave used as a standalone.

Dose-response and time-course

The trajectory is not linear. Appetite reduction and craving suppression appear within the first 2 to 4 weeks; weight-loss velocity peaks between months 3 and 6 and plateaus by month 12. Blood pressure and mood are watched at every visit through the first 6 months.

5-step Contrave protocol

This is the pathway that matches the FDA 2014 labelling, the AACE 2016 Obesity Clinical Practice Guideline (Garvey), and the ADA 2024 Standards of Care. Every step is prescriber-mediated.

Step 1: Confirm the indication

Contrave is FDA-approved for adults with BMI ≥ 30, or BMI ≥ 27 with at least one weight-related comorbidity (hypertension, dyslipidemia, or type 2 diabetes) — see the BMI calculator if you need to check. Contrave is not approved under age 18. Positioning within the obesity-medicine armamentarium (Wadden 2020, JAMA): GLP-1 receptor agonists are first-line for most adults who qualify, phentermine-topiramate (Qsymia) is the strongest of the pre-GLP-1 orals, and Contrave is best positioned for reward-driven eating patterns and for patients who cannot use a GLP-1.

Step 2: Screen for exclusions

Absolute contraindications and important precautions before prescribing:

• Chronic opioid use (analgesia loss and precipitated withdrawal from naltrexone) — includes prescription opioids, methadone, and buprenorphine.
• Seizure history or an actively lowered seizure threshold (bupropion doubles baseline seizure risk in vulnerable patients).
• Current or prior eating disorder (bulimia, anorexia) — dramatically raises seizure risk on bupropion.
• Uncontrolled hypertension.
• Within 14 days of an MAOI (phenelzine, tranylcypromine, isocarboxazid, selegiline, linezolid) — risk of hypertensive crisis.
• Current alcohol, benzodiazepine, barbiturate, or antiepileptic-drug withdrawal — all raise seizure risk.
• Pregnancy or breastfeeding — no adequate data; not recommended.
• Concurrent bupropion product (Wellbutrin, Zyban, generic bupropion) — do not stack.

Step 3: Baseline blood pressure and mood

Bupropion can raise systolic blood pressure by roughly 1 to 2 mmHg on average — a small mean effect that matters more in people with borderline or uncontrolled hypertension. Baseline and follow-up BP measurement is standard (see blood pressure and weight loss for the broader picture). Baseline PHQ-9 or equivalent screening is appropriate given the boxed suicidal-behaviour warning; explicit patient counselling on what to watch for (new or worsening depression, agitation, irritability, or suicidal ideation) and a clear plan for immediate discontinuation and clinician contact if any of those appear.

Step 4: Titrate over 4 weeks

The titration schedule above — 1 tablet in the morning for week 1, then adding one tablet per week — is designed to minimize nausea, insomnia, and headache. Take with a low-fat meal (a high-fat meal raises bupropion exposure enough to increase seizure risk per the prescribing information). If nausea or insomnia is limiting, slow the titration rather than abandoning the drug — the COR-trial discontinuation curve shows most tolerance issues resolve by week 8.

Step 5: Assess at week 16 — the FDA stop rule

At week 16 on the target dose (32/360 mg), reweigh. If you have not lost at least 5% of baseline body weight, discontinue Contrave per FDA labelling — continued exposure is not justified. If you have lost 5% or more, continuing therapy is reasonable, with ongoing BP and mood monitoring. There is no formal FDA taper requirement, but abrupt discontinuation of high-dose bupropion after long exposure is worth avoiding in patients with any seizure-risk features; a step-down over 1 to 2 weeks is common practice.

What treatments actually do — comparison

Special situations

Chronic opioid users (post-surgical, chronic pain, MOUD)

This is the single most important safety line. If you are on any daily opioid — prescription analgesic for chronic pain, methadone or buprenorphine for opioid use disorder, or opioid analgesia in the perioperative window — Contrave is contraindicated (naltrexone prescribing information; FDA 2014 Contrave labelling). Two things go wrong at once: naltrexone blocks the analgesic effect of the opioid, and it precipitates withdrawal — often severe, sometimes requiring emergency care. The rule of thumb is 7 to 10 days off short-acting opioids and 10 to 14 days off methadone or buprenorphine before Contrave can be considered, and a supervised naltrexone challenge is usually part of the workup. If an emergency requires opioid analgesia while a patient is on Contrave, the emergency team needs to know — see opioids and weight changes for the broader framing.

Comorbid depression

Bupropion (as part of Contrave) is independently effective for major depressive disorder (APA 2016 MDD guideline; Vieta 2018, The Lancet). For patients with mild-to-moderate comorbid depression, Contrave can function as the antidepressant — do not stack with a separate bupropion product (Wellbutrin, Zyban, generic bupropion), and do not combine with an MAOI or within 14 days of stopping one. SSRIs and SNRIs can be combined with Contrave with dose adjustment and closer monitoring (bupropion inhibits CYP2D6 and can raise levels of some SSRIs). Baseline PHQ-9 and follow-up mood screening are standard given the boxed warning. See depression and weight loss and antidepressants and weight changes for the broader picture.

Tobacco dependence

Bupropion (sold under the brand Zyban for this indication) is an FDA-approved smoking cessation drug. For adults who are both trying to quit smoking and pursuing weight loss, Contrave can serve double duty — reward-driven eating and reward-driven smoking overlap in the mesolimbic dopaminergic pathway, and the mechanistic rationale is direct. Do not stack Contrave with Zyban or with nicotine-replacement bupropion combinations. Baseline and follow-up BP monitoring remains standard.

Reward-driven eating patterns

This is the strongest niche. Patients whose eating pattern is dominated by cravings, palatability, and evening grazing — rather than by hunger — often respond disproportionately well to Contrave because the mesolimbic dopamine and endogenous-opioid pathways that drive that behaviour are exactly what naltrexone and bupropion modulate (Billes 2014). GLP-1 medications reduce hunger and slow gastric emptying, but they do less to blunt the reward pull of a highly palatable food that is not driven by hunger in the first place. See emotional eating and weight loss and binge eating disorder and weight loss for the surrounding behavioural picture — noting that active binge-eating disorder itself is a Contrave precaution because eating disorders raise seizure risk on bupropion.

Adolescents

Contrave is not FDA-approved under age 18 and should not be prescribed in that population. The obesity-medicine options for adolescents are lifestyle intervention, liraglutide (approved down to age 12), semaglutide (approved down to age 12 in 2022), and — as of the 2022 FDA update — phentermine-topiramate (Qsymia). See adolescent and teen weight management for the broader picture.

Contrave with — or switching to — a GLP-1

There is no direct pharmacokinetic interaction between Contrave and semaglutide or tirzepatide, and the mechanisms are complementary. In practice, most clinicians pick one drug and optimize it before considering combination, because the GI burden of the GLP-1 stacked on the nausea burden of Contrave often makes both harder to tolerate, and the added monthly cost is substantial. When switching from Contrave to a GLP-1, patients often gain the larger weight-loss effect of the GLP-1 but lose the reward-circuit suppression that was helping with cravings — the trade-off is real and worth discussing before the switch. When switching from a GLP-1 to Contrave, the reverse trade-off applies. See prescription weight loss medications and semaglutide vs tirzepatide for the broader comparison.

Red flags — when to call for help

Some symptoms on Contrave are not routine and warrant same-day evaluation or emergency care.

• New-onset seizure or loss of consciousness — call 911. Discontinue Contrave; do not restart without specialist evaluation (bupropion prescribing information).
• Severe hypertensive emergency (systolic ≥180 or diastolic ≥120 mmHg with headache, chest pain, vision change, shortness of breath) — call 911.
• New or worsening depression, agitation, hostility, panic, mania, or suicidal thoughts or behaviour — discontinue Contrave and contact your prescriber immediately; if in acute crisis, call or text 988 (Suicide and Crisis Lifeline).
• Precipitated opioid withdrawal after a dose of Contrave (severe body aches, agitation, sweating, GI distress after an unrecognized opioid exposure) — seek urgent evaluation; disclose current naltrexone exposure to the treating team.
• Severe insomnia unrelieved by moving the evening dose earlier — dose reduction or discontinuation.
• Suspected overdose or accidental ingestion — call Poison Control at 1-800-222-1222 (US) immediately. Bupropion overdose carries a substantial seizure risk.

How this connects to the rest of the site

Contrave sits in the obesity-medicine cluster and overlaps with several other guides. For the broader medication landscape, see prescription weight loss medications, phentermine for weight loss, and weight loss drug safety. For the GLP-1 comparison, see semaglutide for weight loss and tirzepatide for weight loss. For the depression and reward-eating overlap, see antidepressants and weight changes, depression and weight loss, emotional eating and weight loss, and binge eating disorder and weight loss. For opioid-related contraindications, see opioids and weight changes. For the surrounding care setting, see medical weight loss programs, weight loss injections near me, and telehealth weight loss.

Bottom line

Contrave is not the strongest weight-loss drug on the market — a GLP-1 will beat it on the scale by roughly a factor of two, and tirzepatide will beat it by roughly a factor of three. What Contrave is, is a targeted tool for reward-driven and craving-dominant eating, an option for adults who cannot use a GLP-1, and a double-duty drug for patients with comorbid depression or tobacco dependence. It comes with a boxed suicidal-behaviour warning inherited from bupropion, a real seizure risk at the approved dose, and an opioid-antagonism liability that makes it categorically off-limits for anyone on chronic opioids. Screening, titration with a low-fat meal, baseline BP and mood, and the FDA week-16 stop rule are the safety architecture that keeps Contrave a reasonable choice. If those constraints fit you and your prescriber, the roughly 6% mean weight loss it delivers — layered on top of the calorie-deficit and behavioural work that everything downstream depends on — is a real, useful result.

Contrave FAQ

How much weight loss should I expect? Roughly 6% at 56 weeks on 32/360 mg (Greenway 2010 COR-I; Apovian 2013 COR-II) — about half of semaglutide 2.4 mg and one-third of tirzepatide 15 mg.

Who is it best for? Reward-driven eaters, adults who cannot use a GLP-1, and patients with comorbid depression or tobacco dependence.

Who should not take it? Anyone on chronic opioids, anyone with a seizure history or eating disorder, anyone with uncontrolled hypertension, and anyone within 14 days of an MAOI.

How is it dosed? Weekly titration over 4 weeks to 2 tablets AM + 2 tablets PM (32 mg naltrexone / 360 mg bupropion daily), always with a low-fat meal.

What is the FDA stop rule? Discontinue if <5% weight loss at week 16 (FDA 2014 labelling).

Can I combine it with a GLP-1? No direct interaction; usually pick one and optimize first because the GI and nausea burden stacks.

What is the boxed warning? Suicidal thoughts and behaviour (inherited from bupropion) — screen mood at baseline and at every visit; if in crisis, call or text 988.