Muscarinic antipsychotics
Antipsychotics that act through muscarinic M1 and M4 receptors instead of blocking dopamine D2 receptors. The first is xanomeline with trospium.
What they are
A new class for schizophrenia. Its central muscarinic agonist is paired with a peripheral antimuscarinic so that the brain receives the muscarinic signal while the gut, glands and bladder are partly protected.
Mechanism of action
Mice lacking the M4 receptor show a psychosis-like phenotype, which made M4 agonism a candidate antipsychotic mechanism. Xanomeline is an M1- and M4-preferring agonist that acts in the brain. Trospium is a quaternary antimuscarinic that stays mostly outside the brain; it is added to limit xanomeline's cholinergic effects in the rest of the body.
Target: Muscarinic M1 and M4 receptors (central agonist) plus peripheral muscarinic receptors (antagonist)
Drugs in this class
Test yourself
Think of the answer, then tap the question to see it.
Which receptors does xanomeline stimulate?
Muscarinic M1 and M4 receptors.
Why is trospium combined with xanomeline?
It blocks peripheral muscarinic receptors but barely enters the brain, reducing xanomeline's peripheral cholinergic effects.
How does this class differ from all earlier antipsychotics?
It does not work by blocking or partially stimulating dopamine D2 receptors.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Xanomeline and trospium chloride: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026).
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Representative model, for educational purposes only.