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Printed on 7/20/2026
For informational purposes only. This is not medical advice.
The Anticholinergic Cognitive Burden (ACB) score quantifies cumulative anticholinergic exposure from a patient's medication list. Higher totals are associated with increased risk of cognitive impairment, delirium, falls, and other adverse outcomes, especially in older adults.
Formula: ACB total = sum of anticholinergic burden points assigned to each medication.
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Begin with a complete and reconciled medication list including all prescription medications, over-the-counter drugs, and supplements. Medication reconciliation is the foundation of ACB scoring — an incomplete list produces an unreliable score. Pay particular attention to medications the patient takes intermittently or as needed (PRN), as these are frequently omitted from lists but may contribute substantial anticholinergic burden. Common classes with high anticholinergic potential include bladder antimuscarinics (oxybutynin, tolterodine, solifenacin), first-generation antihistamines (diphenhydramine, hydroxyzine), tricyclic antidepressants (amitriptyline, nortriptyline, imipramine), antipsychotics (olanzapine, quetiapine, clozapine), antispasmodics, and certain antidepressants (paroxetine).
Score each medication using the published ACB scale: 0 points for no known anticholinergic activity; 1 point for possible or mild anticholinergic activity (theoretical pharmacological effect but limited clinical evidence for cognitive adverse effects — e.g., ranitidine, furosemide, metoprolol); 2 points for moderate anticholinergic activity with some evidence for cognitive effects (e.g., amantadine, pethidine/meperidine); 3 points for definite high anticholinergic activity with established evidence for cognitive adverse effects (e.g., diphenhydramine, oxybutynin, amitriptyline, paroxetine, olanzapine, promethazine, chlorpromazine, hyoscine). Sum all medication scores to produce the total ACB score.
Interpret total ACB scores in clinical context: 0-2 indicates low burden (minimal anticholinergic concern); 3 or higher indicates clinically meaningful anticholinergic burden associated with increased risk of cognitive decline, delirium, falls, and functional impairment in older adults. A landmark study (Fox et al., 2011) found that ACB scores above 3 were associated with a 1.46-fold increased risk of cognitive decline over 2 years. For each point above 3, review the clinical necessity of high-burden medications, consider lower-burden alternatives, assess whether the condition being treated could be managed non-pharmacologically, and prioritize medications scoring 3 for deprescribing evaluation with the prescribing physician.
Geriatricians, clinical pharmacists, primary care physicians
The ACB score is a cornerstone tool in comprehensive medication review for older adults, particularly those with polypharmacy (5+ medications). High ACB scores identify which medications are contributing the most cognitive risk and should be prioritized for deprescribing review. Clinical pharmacists use the ACB score to structure medication optimization consultations, targeting medications with ACB score 3 for evidence-based alternatives or discontinuation. ACB-guided medication reviews have demonstrated cognitive and functional improvements in randomized controlled trials.
Neurologists, geriatricians, memory clinic teams
Observational studies linking cumulative anticholinergic exposure to dementia risk have created clinical urgency around identifying and reducing unnecessary high-ACB medication burden in midlife and older adults. ACB scoring helps memory clinic teams identify potentially modifiable risk factors in patients referred for cognitive evaluation. In patients with mild cognitive impairment, reducing ACB score through deprescribing or substitution is a standard component of cognitive risk reduction counseling, even though causality is not definitively established.
Hospitalists, geriatric consult teams, delirium prevention programs
Anticholinergic medications are among the most potent modifiable precipitants of delirium in hospitalized older adults. The ACB score helps delirium prevention teams rapidly identify which medications on a patient's admission or inpatient list carry the highest cognitive risk. The HELP (Hospital Elder Life Program) and similar programs include anticholinergic medication review as a core delirium prevention intervention, using ACB scoring to prioritize which medications to discontinue or substitute upon admission or at the first sign of confusion.
Fall-prevention program coordinators, pharmacists, nursing homes
Anticholinergic medications contribute to falls through sedation, dizziness, orthostatic hypotension, and impaired psychomotor function. ACB score 3 or higher is associated with significantly elevated fall risk, particularly when combined with benzodiazepines, opioids, or antihypertensives. Falls prevention programs use ACB scoring to identify medication-related fall contributors that can be reduced or eliminated. Deprescribing high-ACB medications has demonstrated fall rate reductions in older community-dwelling adults in multiple randomized trials.
LTC pharmacists, medical directors, nursing home staff
Nursing home residents have among the highest anticholinergic medication burden of any patient population, reflecting the prevalence of urinary incontinence, behavioral symptoms of dementia, and depression treated with high-ACB medications. ACB scoring is used in long-term care quality improvement programs to identify residents with potentially inappropriate high-burden medication regimens under criteria such as the Beers Criteria and STOPP/START guidelines. Facilities that implement systematic ACB review have demonstrated reductions in chemical restraint use, fall rates, and hospitalization.
Most medications scoring 3 on the ACB scale are also listed on the American Geriatrics Society Beers Criteria for potentially inappropriate medication use in older adults and the STOPP (Screening Tool of Older Persons' Prescriptions) criteria. When an ACB score is elevated, cross-reference against Beers and STOPP to identify medications that have multiple independent reasons for review. Diphenhydramine, for example, is flagged by Beers for cognitive impairment, falls risk, and delirium — three independent reasons to deprescribe in older adults beyond its ACB contribution.
Not all medications in the ACB framework carry equal clinical weight. Medications with ACB score 3 (definite high anticholinergic activity) represent the highest-yield deprescribing targets and should be reviewed before medications scoring 1-2. High-burden medications include diphenhydramine (sold OTC as Benadryl and in most sleep aids), oxybutynin (immediate release has higher CNS penetration than extended release and is particularly problematic), tricyclic antidepressants prescribed for pain, and paroxetine. Substitution of these medications with lower-burden alternatives often provides equivalent clinical benefit with substantially reduced anticholinergic risk.
One of the most common underestimates of anticholinergic burden occurs because OTC medications are not included in the prescription medication list. Diphenhydramine (ACB score 3) is ubiquitous in OTC sleep aids (Benadryl, Unisom, ZzzQuil, Tylenol PM) and allergy medications. Many older adults take these nightly without disclosing them to physicians because they perceive them as harmless. Specifically ask about sleeping pills, allergy medications, and any medications purchased without a prescription when conducting medication reconciliation for ACB scoring.
Multiple anticholinergic burden scales exist: the ACB scale, the Anticholinergic Risk Scale (ARS), the Anticholinergic Drug Scale (ADS), and the Drug Burden Index (DBI). These scales do not assign identical scores to all medications and may give substantially different totals for the same medication list. When interpreting ACB scores across clinical settings or research studies, verify which scale was used. The ACB scale is among the most widely used in research and clinical practice, but institutional protocols may use the ARS or other scales. Document which scale was applied when recording results.
A common misconception is that deprescribing one anticholinergic medication is insufficient to produce measurable cognitive benefit if others remain. However, evidence suggests that even modest ACB score reductions (1-2 points) are associated with improved cognitive performance and reduced delirium incidence when achieved through targeted deprescribing of high-burden medications. The goal need not be ACB score 0 — for many older adults with multiple comorbidities, this is not achievable. Reduction from ACB 6 to ACB 3 represents meaningful risk reduction and is a realistic deprescribing target.
Not all high-ACB medications can or should be deprescribed. Some medications scoring 3 on the ACB scale are occasionally the best available option for the condition being treated: clozapine for treatment-resistant schizophrenia, amitriptyline at low dose for neuropathic pain with no better alternative, or oxybutynin for severe overactive bladder unresponsive to behavioral therapy. In these cases, the clinical benefit may outweigh anticholinergic risk. Document the risk-benefit discussion, ensure the patient and family are aware of the cognitive risks, use the lowest effective dose, and reassess regularly whether continuation is still justified.
The most effective ACB-guided medication reviews include specific lower-burden alternative recommendations, not just identification of problematic medications. For oxybutynin, alternatives include mirabegron (ACB 0) or beta-3 agonists. For amitriptyline used for sleep, melatonin or CBT-I are low-risk alternatives. For first-generation antihistamines for allergies, loratadine or fexofenadine (ACB 0-1) are effective alternatives. For paroxetine, sertraline or escitalopram carry lower anticholinergic burden. Having specific substitution recommendations ready dramatically increases the likelihood that prescribers will act on ACB review findings.
ACB scoring is not a one-time exercise — it should be repeated after any significant medication change, hospitalization, or functional decline to ensure that anticholinergic burden remains at the lowest clinically achievable level. Many patients accumulate new anticholinergic medications during hospitalizations (antiemetics, antihistamines for reactions, antispasmodics for abdominal pain, bladder medications for catheter-related discomfort) that are continued inappropriately after discharge. Discharge medication reconciliation is a key opportunity to recalculate ACB score and remove medications started for transient indications.
ACB has broad observational evidence linking higher burden with adverse geriatric outcomes.
Higher ACB totals indicate greater cumulative anticholinergic risk and support medication review.
Use in older adults and polypharmacy workflows to identify potentially modifiable medication-related cognitive risk.
Different anticholinergic scales exist and do not always assign identical medication weights.
For related assessments, see DOSS, UB-2 Delirium and 4AT.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
April 21, 2026 · trust-baseline
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