Anticholinergic Burden Calculator
Search and Add Medications
Type a drug name or brand name. Click a result to add it to the list. Medications already added are greyed out.
Why Anticholinergic Burden Matters
Anticholinergic drugs block muscarinic acetylcholine receptors. Peripheral effects include dry mouth, constipation, urinary retention, blurred vision, and tachycardia. Central effects in older adults include confusion, delirium, cognitive impairment, and falls. These effects are cumulative: a patient on four drugs each scoring 1 has the same total burden as one drug scoring 4.
A landmark 2019 cohort study (Coupland et al., JAMA Internal Medicine) found each additional ACB point was associated with a 26% increase in odds of dementia diagnosis. The association held after adjustment for depressive symptoms and other confounders.
Which scale to use? A 2015 systematic review (Salahudeen et al., JAGS) found that while individual drug rankings differ between scales, all predict similar adverse outcomes. The ACB scale has the most large-scale validation and is recommended in the STOPP/START v3 criteria (2022) for routine use in older adult prescribing review.
Concordance: For the most commonly implicated drugs (TCAs, first-generation antihistamines, antimuscarinics for OAB), all three major scales agree on high scores. Disagreement is greatest for drugs with borderline serum anticholinergic activity.
STOPP v3 (2022) flags these drugs as explicitly inappropriate in older adults:
- Any anticholinergic drug in patients with cognitive impairment, delirium, or dementia (regardless of score) -- risk of worsening confusion and functional decline
- Oxybutynin -- highest anticholinergic burden of commonly used OAB agents; consider solifenacin (funded NZ) or mirabegron (beta-3 agonist, non-anticholinergic)
- Promethazine -- as antiemetic or antihistamine; better alternatives available
- Paroxetine -- most anticholinergic SSRI; switch to sertraline or escitalopram where possible
- First-generation antihistamines (chlorphenamine, doxylamine, diphenhydramine) -- for any indication in older adults; use non-sedating antihistamines instead
- Antipsychotics with high anticholinergic burden (chlorpromazine, olanzapine) -- in patients with falls risk or cognitive impairment
- Tertiary TCAs (amitriptyline, imipramine, doxepin) -- as antidepressants, for neuropathic pain, or as sleep aids; switch to nortriptyline if TCA required (lower burden, though still score 3)
NZ HealthPathways note: Review of anticholinergic burden is a standard component of Comprehensive Geriatric Assessment (CGA) in New Zealand. BPAC Best Practice guidance on polypharmacy in older adults (2019) recommends proactive ACB review at all medication reconciliation visits.
Overactive bladder (OAB): Oxybutynin (score 3, worst CNS penetration) should be replaced. Funded NZ alternatives: solifenacin (score 3, better CNS profile than oxybutynin), tolterodine (score 3). Mirabegron (Betmiga, beta-3 agonist, score 0) is an excellent non-anticholinergic option; not funded in NZ as at 2024 but special authority may apply.
Depression in older adults: Avoid tertiary TCAs. If TCA necessary, nortriptyline (score 3) causes fewer cognitive effects than amitriptyline or imipramine at equivalent doses. SSRIs: sertraline and escitalopram have the lowest anticholinergic burden (score 1). Avoid paroxetine (score 2).
Neuropathic pain: Amitriptyline is first-line but contributes significantly to burden. Consider gabapentin, pregabalin (no anticholinergic activity), or duloxetine (score 0-1) in older patients with existing cognitive risk.
Sleep: First-generation antihistamines (doxylamine, diphenhydramine) are all score 3; avoid routinely in older adults. Melatonin (score 0) is preferred; low-dose mirtazapine (score 2) may be appropriate if depression is co-present.
Antiemetics: Prochlorperazine (score 2) and promethazine (score 3) should be replaced by metoclopramide (score 1) or ondansetron (score 0) where possible.
COPD/asthma: Inhaled antimuscarinics (tiotropium, ipratropium) have low systemic absorption and are scored conservatively in this calculator. They should not be withheld for COPD management; the risk-benefit ratio is favourable. Note their contribution to total burden in patients already carrying a high score.
Antipsychotics: Haloperidol (score 1) has the lowest anticholinergic burden of commonly used antipsychotics. Risperidone and aripiprazole are scored 0-1 in most scales. Avoid olanzapine (score 3), chlorpromazine (score 3), and quetiapine (score 2) in patients with existing cognitive impairment.
ACB score of 1-2: Individual studies show marginal cognitive and functional effects. Main concern is additive burden with other drugs. These medications should not be avoided on anticholinergic grounds alone in cognitively intact patients, but should be noted during medication reconciliation.
ACB score of 3-5: Multiple large studies demonstrate increased odds of cognitive impairment, falls, and hospitalisation. Coupland et al. (2019, n=58,769) found ACB score 3+ sustained over 10 years was associated with an odds ratio of 1.54 for dementia. Proactive review and substitution recommended in all patients aged over 65.
ACB score of 6+: Strongly associated with delirium (especially post-operatively), falls with injury, urinary retention, constipation, and impaired quality of life. Urgent deprescribing review indicated. In patients with existing cognitive impairment, an ACB score of 3+ is itself a STOPP criterion.
Important caveats: Scores are derived from population-level data. Individual patients may tolerate high-burden regimens or experience effects at lower scores depending on age, renal/hepatic function, frailty, baseline cognition, and pharmacogenomic variation (notably CYP2D6 for drugs with anticholinergic metabolites). The ACB scale has been validated primarily in adults aged 65 and over.
Full Drug List and ACB Scores
Scores from Fox et al. (2011) ACB scale, updated by Bishara et al. (2017). NZ brand names and subsidy status approximate as at 2025; verify current status on the NZF.
| Drug (generic) | NZ Brand / Notes | Class | ACB Score | Clinical note |
|---|
References
- Fox C, Richardson K, Maidment ID, et al. Anticholinergic medication use and cognitive impairment in the older population: the Medical Research Council Cognitive Function and Ageing Study. J Am Geriatr Soc. 2011;59(8):1477-1483.
- Bishara D, Harwood D, Sauer J, Taylor DM. Anticholinergic effect on cognition (AEC) of drugs commonly used in older people. Int J Geriatr Psychiatry. 2017;32(6):650-656.
- Rudolph JL, Salow MJ, Angelini MC, McGlinchey RE. The anticholinergic risk scale and anticholinergic adverse effects in older persons. Arch Intern Med. 2008;168(5):508-513.
- Salahudeen MS, Hilmer SN, Nishtala PS. Comparison of anticholinergic risk scales and associations with adverse health outcomes in older people. J Am Geriatr Soc. 2015;63(1):85-90.
- Coupland CAC, Hill T, Dening T, Morriss R, Moore M, Hippisley-Cox J. Anticholinergic drug exposure and the risk of dementia: a nested case-control study. JAMA Intern Med. 2019;179(8):1084-1093.
- O'Mahony D, Cherubini A, Guiteras AR, et al. STOPP/START criteria for potentially inappropriate prescribing in older people: version 3. Eur Geriatr Med. 2023;14(4):625-632.
- BPAC NZ. Polypharmacy: managing multiple medicines in older adults. Best Practice J. 2019. https://bpac.org.nz
- New Zealand Formulary (NZF). Drug interaction and anticholinergic burden guidance. https://www.nzf.org.nz [cited 2025].