[PaulHoule]

See https://en.wikipedia.org/wiki/Xanomeline/trospium_chloride

It’s interesting to me that this is a combination medicine because the atypical antipsychotics (say https://en.wikipedia.org/wiki/Quetiapine) are “polypharmacy in a single molecule” in that they bind to both dopamine and serotonin receptors which cancel out terrible side effects such as tardive dyskinesia caused by earlier antipsychotics that work on the dopamine receptors (though most of those bind to histamine receptors causing strong sedation as well.)

[pinewurst]

It’s a combination medicine because the major effect, while deemed desirable in the brain, is not so in the body. The partner drug is a non-brain penetrating suppressant.

[kelavaster]

It's effectively a partial agonist with different subreceptor affinities.