Anticholinergic Medications Among Propranolol, Primidone, Topiramate, and Gabapentin
None of the four medications listed—propranolol, primidone, topiramate, and gabapentin—have clinically significant anticholinergic properties, making them all relatively safe choices for patients with dementia from an anticholinergic burden perspective.
Direct Evidence on These Specific Medications
Topiramate demonstrated anticholinergic activity only at the highest concentrations tested (well above typical therapeutic levels), meaning it shows no meaningful anticholinergic effects at standard doses used in clinical practice 1.
Gabapentin was not found to have any detectable anticholinergic activity in radioreceptor assays measuring anticholinergic burden at therapeutic concentrations 1.
Propranolol and primidone were not identified as having anticholinergic properties in comprehensive reviews of medications with anticholinergic effects 1, 2.
Clinical Context for Dementia Patients
This distinction is particularly important because:
Anticholinergic medications should be avoided in elderly patients with dementia, as they are associated with increased delirium risk, cognitive decline, and functional impairment 3.
High-risk anticholinergics that should be avoided include tricyclic antidepressants, paroxetine, diphenhydramine, cyclobenzaprine, oxybutynin, prochlorperazine, and promethazine—none of which are in your list 3, 4.
Medications with moderate anticholinergic activity (5-15 pmol/mL atropine equivalents) include chlorpromazine, diphenhydramine, nortriptyline, olanzapine, oxybutynin, and paroxetine—again, none of which are your listed medications 1.
Practical Implications for Essential Tremor Treatment
Since these medications are commonly used for essential tremor:
Propranolol and primidone are both Level A (established as effective) treatments for essential tremor and carry no anticholinergic burden 5.
Gabapentin and topiramate are Level B (probably effective) treatments for essential tremor without meaningful anticholinergic effects at therapeutic doses 5.
All four medications can be safely used in patients with dementia from an anticholinergic standpoint, though other side effects and drug interactions should still be monitored 3, 1.
Important Caveat
While none of these medications are anticholinergic, topiramate may show minimal anticholinergic activity in patients receiving higher-than-average doses, those with above-average peak plasma concentrations, or in frail elderly patients 1. However, this is not clinically significant at standard therapeutic doses.