Anticholinergic medications (e.g. benztropine) have been used when starting high potency first generation antipsychotic medications, to reduce the onset of parkinsonism or dystonic reactions (extrapyramidal side-effects; EPS), or to manage parkinsonism as part of ongoing treatment. However, anticholinergic medications can cause substantial side-effects themselves, such as urinary retention, constipation, blurred vision, and cognitive impairment. Anticholinergic medications are found in the Beers Criteria list of medications that are best avoided and potentially inappropriate in older adults. SMI Adviser offers a free webinar on this topic: Psychotropic Medications and Older Adults: Update on Safety Considerations (April 2019).
In younger adults, these medications are also not necessary in most patients taking antipsychotic medications. Given their toxicities, there are often better choices. Patients who are not taking high potency first generation antipsychotic medications usually do not benefit from anticholinergic medication. Many patients who are stable on antipsychotic medication no longer have EPS. Also, the presence of EPS is associated with an increased risk for developing tardive dyskinesia. Alternative approaches to managing EPS include gradual antipsychotic dose reduction to a dosage without EPS, or changing to a different antipsychotic medication. There are now many antipsychotic medications that cause little or no EPS. Also, it should be noted that anticholinergic medications are not an effective treatment for tardive dyskinesia, and can make tardive dyskinesia worse.