The present disclosure provides a method of treating a central nervous system disorder in a patient in need thereof. The method comprises orally administering between 75 mg and 300 mg xanomeline and between 20 mg and 200 mg trospium chloride to the patient during a 24-hour period. The central nervous system disorder is selected from schizophrenia, Alzheimer's disease, Huntington's disease, Parkinson's disease, and Lewy Body dementia, wherein use of the trospium chloride alleviates a side effect associated with use of the xanomeline.