in pictures and a few words
What it is and why it matters
This is a medicine for schizophrenia in adults. It has two substances: one treats, the other quenches its extra action in the body.
- It was approved in the US in 2024
- For the first time in about 70 years, such a medicine works another way
How it was treated before
Earlier medicines muted one signaling substance in the brain. This helped, but it also hit that substance’s other jobs.
- Stiffness, trembling, restlessness
- Weight gain, sleepiness, dulled feelings
- This is the most common reason people quit treatment — and without it the illness returns
A different route
This medicine doesn’t mute that signal. It acts on another brain system that controls the same areas from the other side.
- Not silencing the loudspeaker, but turning down the sound at the input
- The extra signal gets quieter where there is too much of it
Why the second substance
The first substance has been known for about thirty years. It helped but irritated the whole body: nausea, vomiting, sweating, saliva. It was shelved.
- The second substance quenches this extra action in the body
- It barely reaches the brain and doesn’t interfere with treatment
Signs of illness ease
In adults with a flare-up of schizophrenia, signs of the illness eased more over five weeks than in those who got pills without the medicine.
- Other measures in the study also favored the medicine
- The benefit and safety held up after a year of use too
Tested in people. Tested in people: in adults with a flare-up of schizophrenia, compared with pills without the medicine.
No stiffness or extra weight
The main difference: the stiffness, restlessness and weight gain usual for such medicines are practically absent.
- Sleepiness was almost as rare as without the medicine
- For someone who has paid with stiffness and weight for years, this is no small thing
Tested in people. Tested in people: movement problems and weight gain were almost absent — about as in those who got pills without the medicine.
What happens more often
The troubles moved to the belly: nausea, vomiting, constipation and indigestion are noticeably more common than without the medicine. Blood pressure also rises more often.
- Belly troubles are usually mild or moderate
- They are more common early on and ease over time
- Blood pressure is checked during treatment
How it is prescribed
Only a psychiatrist prescribes this medicine and changes treatment.
- If your current medicine works and is tolerated, it’s not worth changing without a reason
- A reason to discuss a switch is poor tolerance of current treatment, not novelty
- The switch follows a plan and is supervised
Important. Don’t change the medicine yourself: replacing treatment that works carries a risk of a flare-up.
Who should see a doctor first
This medicine doesn’t suit everyone. Discuss it with your doctor in advance if you have any of these.
- Marked stomach and bowel problems: they take the main load
- Urinary retention, some glaucomas, other cases where the second substance is not allowed
- The medicine is not for self-treatment: changing treatment only under supervision
Important. The decision to prescribe and any change of treatment is made by a psychiatrist.
In one sentence
For the first time in about 70 years, a schizophrenia medicine works another way: almost without stiffness and extra weight, but more often with nausea and constipation — under a psychiatrist’s care.
Key points
Xanomeline-trospium (Cobenfy) is a schizophrenia treatment for adults, approved by the FDA in September 2024. For the first time in roughly 70 years it does not block dopamine receptors: the action runs through the muscarinic system.
| Situation | How it helps | What human studies showed |
|---|---|---|
| Schizophrenia in adults | eases symptoms without blocking dopamine | EMERGENT-2 (Lancet, 2024), 252 participants in an acute exacerbation of schizophrenia, 5 weeks: the PANSS total score fell by 21.2 versus 11.6 points on placebo (difference −9.6; 95% CI −13.9 to −5.2; p<0.0001; effect size 0.61); all secondary endpoints favoured the drug [1] |
| Movement and metabolic effects | the movement and metabolic effects typical of the class are essentially absent | extrapyramidal symptoms 0% versus 0% on placebo, akathisia 1% versus 1%, weight gain 0% versus 1%, somnolence 5% versus 4% [1] |
| Long-term use | the effect holds | 52-week open-label extension (Am J Psychiatry, 2026): efficacy and the safety profile hold across a year [2] |
How it helps
Seventy Years of One Idea
In the 1950s it emerged that the substances easing psychosis blocked dopamine D2 receptors. The dopamine hypothesis of schizophrenia grew out of that observation, and with it every generation of antipsychotics from the first agents to the modern ones.
The approach works. But dopamine is involved in far more than psychosis, and blockade hits all of its functions at once. Hence the familiar catalogue: movement disorders (rigidity, tremor, akathisia), raised prolactin, weight gain and metabolic shifts, sedation and blunted emotion.
It is the side effects, not a lack of efficacy, that most often make a patient abandon treatment. And abandoned treatment in schizophrenia means relapse.
A Different Way Into the Same System
Xanomeline acts on the muscarinic acetylcholine receptors, primarily the M1 and M4 subtypes. They sit in the same brain circuits involved in psychosis, but they govern those circuits from another side.
Simplified: activating M4 indirectly reduces excessive dopamine transmission where it is excessive, instead of blocking receptors outright everywhere. The difference is roughly that between muffling a loudspeaker and turning the signal down at the input.
Why This Drug Sat on a Shelf for Thirty Years
The striking part of the story is that xanomeline is not a new molecule. It was tested back in the 1990s in Alzheimer's disease. It worked: patients' psychotic symptoms eased. But muscarinic receptors exist throughout the body, and the drug activated all of them — nausea, vomiting, sweating, salivation, cramps. Tolerability proved unacceptable and development was halted.
The solution found two decades later was not chemical but engineering. Trospium was added: a substance that blocks the very same muscarinic receptors but barely crosses the blood-brain barrier.
| Xanomeline | Trospium | |
|---|---|---|
| What it does | Activates muscarinic receptors | Blocks muscarinic receptors |
| Where it acts | Brain and body | Essentially body only |
| What it is for | The therapeutic effect | Quenching the other's side effects |
| Crosses into the brain | Yes | Essentially no |
What This Changes In Practice
For a patient who has lived for years with an antipsychotic and paid for it in rigidity, extra weight and constant drowsiness, a drug with a different set of problems is not a cosmetic improvement. Intolerance is what destroys treatment most often.
How it is prescribed
Any prescription, and any change of therapy, is a psychiatrist's decision.
▸Replacing working therapy carries its own risk of relapse, so the reason to discuss a switch is intolerance of the current regimen, not novelty as such. ▸Blood pressure monitoring is part of follow-up.
Who should see a doctor first
| Adverse event | Cobenfy | Placebo |
|---|---|---|
| Nausea | 19% | 6% |
| Vomiting | 14% | 1% |
| Constipation | 21% | 10% |
| Dyspepsia | 19% | 8% |
| Raised blood pressure | 10% | 1% |
In a pooled analysis of the five-week trials (J Clin Psychiatry, 2025), the gastrointestinal effects were mostly mild to moderate, arose early in treatment and eased over time [3].
Who It Is Not For
▸Patients with significant gastrointestinal problems: that is the system carrying the load. ▸In urinary retention, certain forms of glaucoma and other states where an anticholinergic component is contraindicated. ▸Anyone whose current therapy works and is well tolerated: changing it without cause is risk without gain. ▸As self-medication or a self-directed switch — changing an antipsychotic is done only under supervision.
Bottom Line
▸The first mechanism in ~70 years in schizophrenia that does not rest on dopamine blockade. ▸An engineering solution: an old molecule was rescued by a second one that quenches its side effects without entering the brain. ▸Efficacy confirmed: PANSS −21.2 versus −11.6 on placebo, effect size 0.61. ▸Movement disorders and weight gain are essentially absent — the key clinical distinction. ▸What to keep in mind — nausea, vomiting, constipation and raised blood pressure markedly more often than on placebo.
Treatment can be discussed at a consultation; the drug can be ordered here.
References
1. Kaul I, et al. Efficacy and safety of the muscarinic receptor agonist KarXT (xanomeline-trospium) in schizophrenia (EMERGENT-2) in the USA: results from a randomised, double-blind, placebo-controlled, flexible-dose phase 3 trial. Lancet. 2024;403(10422):160–170. PMID 38104575
2. Kaul I, et al. Long-Term Safety and Efficacy of Xanomeline and Trospium Chloride in Schizophrenia: A 52-Week Open-Label Extension Trial. Am J Psychiatry. 2026;183(3):183–192. PMID 41634905
3. Kaul I, et al. Safety and Tolerability of Xanomeline and Trospium Chloride in Schizophrenia: Pooled Results From the 5-Week, Randomized, Double-Blind, Placebo-Controlled EMERGENT Trials. J Clin Psychiatry. 2025;86(1). PMID 40047530
4. COBENFY (xanomeline and trospium chloride) — US Prescribing Information, Bristol Myers Squibb.
Caveats
An effect size of 0.61 is moderate by convention [1].
What cannot be claimed yet:
▸That it is more effective than modern antipsychotics — no head-to-head trials were run; the comparator was placebo. ▸That it is safer overall: it is safer on some measures and worse on others. ▸What happens over years: 52 weeks is the longest follow-up available, and schizophrenia is treated over decades; the long-range effects of sustained muscarinic activation have not been measured on those timescales. ▸That it helps in treatment-resistant disease — there is no separate indication for that.
This material is for information only and does not replace a consultation with a doctor.
Key facts
- The combination of xanomeline and trospium (brand name Cobenfy, Bristol Myers Squibb) was approved by the FDA in September 2024 for schizophrenia in adults; it is the first fundamentally new mechanism in schizophrenia in roughly 70 years: the drug does not block dopamine receptors but activates muscarinic M1 and M4 receptors.
- Xanomeline has been known since the 1990s; trospium was added for no therapeutic purpose of its own: it blocks the same receptors but barely crosses into the brain — quenching side effects in the body while leaving xanomeline's central action intact.
- EMERGENT-2 (Lancet, 2024): 252 participants; the PANSS total score fell by 21.2 points versus 11.6 on placebo over 5 weeks (difference −9.6; 95% CI −13.9 to −5.2; p<0.0001; effect size 0.61); a 52-week open-label extension (Am J Psychiatry, 2026) confirmed that efficacy and the safety profile hold over a year of treatment.
- The decisive difference shows in tolerability: extrapyramidal symptoms 0% in both arms, akathisia 1% versus 1%, weight gain 0% versus 1%, somnolence 5% versus 4%.
- Gastrointestinal effects are more frequent than on placebo — nausea 19% versus 6%, vomiting 14% versus 1%, constipation 21% versus 10%, dyspepsia 19% versus 8% — as is raised blood pressure (10% versus 1%); blood pressure monitoring is part of follow-up.
