Has anyone compared Qsymia and Contrave in the same trial?

No head-to-head trial has compared these two drugs. Qsymia's figures come from CONQUER (56 weeks) and Contrave's from COR-BMOD (56 weeks), which enrolled different people for different lengths of time. Numbers from separate trials can be read side by side, but they are not a measured difference.

What does each one cost per month?

Qsymia is listed at $30–$400/month (generic; brand runs to $400). Contrave is listed at $100–$400/month. The full price note for each is set out in the cost section above. What you pay depends on your insurance, your dose and your pharmacy.

Can I switch from Qsymia to Contrave?

Switching between weight-loss medicines is a decision for the prescriber who knows your history, your other medicines and how you have responded so far — this site cannot make it for you. What switching involves in practice, including dose steps and the gap between drugs, is set out on the switching page.

Which side effects were reported most often?

In CONQUER (56 weeks), the reaction reported most often with phentermine / topiramate ER was dry mouth — 21% of participants. In COR-I (56 weeks), the reaction reported most often with naltrexone / bupropion ER was nausea — 33% of participants. Rates come from different trials with different participants, and a rate is not a prediction for any one person.

Qsymia vs Contrave: trials compared

At a glance

Qsymia and Contrave compared on form, trial results, cost and reported side effects
Attribute	Qsymia	Contrave
Form	Daily capsule	Twice-daily tablet
How often	Daily oral capsule — no injection	Twice-daily oral tablet — no injection
Weight loss in trials	Up to 9.8% — CONQUER (56 weeks)	Up to 9.3% — COR-BMOD (56 weeks)
FDA approved	2012	2014
Made by	Vivus	Currax Pharmaceuticals
How it works	Phentermine suppresses appetite by triggering the release of adrenaline-like chemicals in the brain's hunger control centre.	Bupropion activates appetite-suppressing nerve cells in the brain's hunger control centre (the hypothalamus).
Monthly cost, self-pay	$30–$400/mogeneric; brand runs to $400	$100–$400/mo
Most reported reaction	Dry mouth 21% (CONQUER)	Nausea 33% (COR-I)

Every figure in this table is read from the same trial and label records used everywhere else on this site.

Weight loss in each drug's main trial

No head-to-head trial has compared these two drugs.

Qsymia(phentermine / topiramate ER)9.8%

CONQUER (56 weeks)

Contrave(naltrexone / bupropion ER)9.3%

COR-BMOD (56 weeks)

In clinical trials, participants taking phentermine / topiramate ER lost on average up to 9.8% of their starting body weight, and participants taking naltrexone / bupropion ER lost on average up to 9.3%. Those numbers come from two different studies: CONQUER enrolled 2,487 adults with obesity and at least 2 weight-related health conditions over 56 weeks against placebo, while COR-BMOD enrolled adults with obesity, with intensive behaviour therapy over 56 weeks against placebo + intensive behaviour therapy. Who took part, how long each trial ran and what each drug was measured against all move the percentage, so the two figures are not a measured difference between the drugs.

Monthly cost, self-pay

The bar spans the range in each drug's price record — lowest listed price to highest.

Qsymia$30–$400/mo

generic; brand runs to $400

~$30–$80/month generic; ~$200–$400/month brand (Qsymia).

Contrave$100–$400/mo

~$100–$400/month (brand). Generic available in some markets.

Self-pay prices are what the manufacturer or the pharmacy lists, not what most people end up paying. Qsymia: $30–$400/month. Contrave: $100–$400/month. Insurance, dose and pharmacy all change both figures.

Side effects reported in the trials

Both trials reported 3 reactions in common. Each rate is the percentage of participants who reported it in the trial named beside it, so the two columns are not from the same study.

Dry mouth

Qsymia · CONQUER21%

Contrave · COR-I8%

Constipation

Qsymia · CONQUER17%

Contrave · COR-I19%

Dizziness

Qsymia · CONQUER9%

Contrave · COR-I10%

A rate is the share of trial participants who reported that reaction, not a prediction for any one person.

How they differ in practice

How you take it

Qsymia — Once-daily extended-release capsule
Contrave — Oral extended-release tablet, twice daily

Dose build-up

Qsymia — 3.75/23 mg → 15/92 mg, titrated over 14 weeks
Contrave — titrated to 32/360 mg/day over 4 weeks

Where a drug is not listed here, its prescribing information sets out its own dose steps.

How soon it acts

Qsymia — Appetite suppression typically begins within the first week; significant weight loss by 12–16 weeks
Contrave — Appetite and craving changes typically within 4–8 weeks; significant weight loss by 16–24 weeks

Heart and metabolic findings

Qsymia — In CONQUER, there were significant reductions in blood pressure, waist circumference, triglycerides and blood glucose.
Contrave — The LIGHT cardiovascular outcomes trial was stopped early, because of a protocol violation.

As stated in each drug’s trial record — not a claim about which drug protects the heart more.

Other findings recorded

Qsymia — Generic now available (from 2025) — significantly lower cost than GLP-1 drugs; improved blood pressure and triglycerides in CONQUER trial
Contrave — May help specifically with emotional eating and food cravings; bupropion's antidepressant effect may be beneficial if low mood contributes to overeating

If you stop taking it

Qsymia — Weight regain after stopping is expected.
Contrave — Weight regain after stopping is expected.

Common questions

Written and maintained by one person · Built with agentic AI tools · Every number checked against the cited trial · Not medical advice

How this site is built →

Next step most people take

Compare all optionsEvery approved drug side by side, plus the other head-to-head pages Qsymia in fullQsymia — results, side effects, cost and how it is taken Contrave in fullContrave — results, side effects, cost and how it is taken Take the option finder quizAnswer a few questions and see which options fit your situation

Built with agentic AI tools and not a substitute for medical advice

Last reviewed: September 2026

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Medical disclaimer: This website is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any treatment. Prices shown are United States self-pay or list prices and vary by insurance and country.