Polypharmacy Risk Calculator: Medicine Count, High-Risk Groups and Review Checklist
Count regular medicines against the polypharmacy (5+) and hyperpolypharmacy (10+) thresholds, see the possible drug-pair load, tick high-risk medicine groups from the Beers and STOPP criteria to flag risky combinations, and get a medication-review suggestion.
How it works
polypharmacy = 5+ regular medications · hyperpolypharmacy = 10+ · possible interacting pairs = n × (n − 1) ÷ 2 · one more medicine adds n pairs · flags: ticked high-risk groups (Beers / STOPP) and known risky combinations
Polypharmacy is most often defined as taking five or more regular medicines a day; a review of 110 studies found this was the most common definition. Ten or more is often called hyperpolypharmacy. Many medicines can be needed at once, so a high count is not automatically wrong. Still, each added medicine raises the chance of side effects, interactions, prescribing cascades (treating a side effect with another drug) and missed doses. The number of possible drug pairs grows fast, n(n − 1) ÷ 2: five medicines make 10 pairs, ten make 45, and each new medicine adds as many pairs as you already take. Most pairs are harmless, so this is a measure of complexity, not a count of interactions. Ticking the medicine groups you take adds the parts that matter most. These groups are blood thinners, NSAIDs, kidney-sensitive blood-pressure medicines, diuretics, insulin and sulfonylureas, and the CNS-active groups (opioids, sleeping pills, antipsychotics, antidepressants, antiepileptics and gabapentinoids). Strongly anticholinergic medicines are flagged separately. The calculator flags combinations named in the American Geriatrics Society Beers Criteria and other prescribing guidance: three or more CNS-active groups, an opioid with a benzodiazepine or with gabapentin or pregabalin, a blood thinner with an NSAID, and the ACE inhibitor/ARB + diuretic + NSAID "triple whammy". The review suggestion is a plain-language prompt, not a validated score. Bring a full list, including over-the-counter medicines and supplements, to a pharmacist or doctor.
Worked example
Someone aged 70 on 6 regular medications is in the polypharmacy band, with 6 × 5 ÷ 2 = 15 possible drug pairs; a seventh medicine would add 6 more pairs. With no high-risk groups ticked, the suggestion is a structured review at least once a year. If they also took an opioid and a sleeping pill, the calculator would flag that combination (Beers: avoid) and suggest asking for a review soon. Rising to 10 medications would create 10 × 9 ÷ 2 = 45 pairs.
Sources: Masnoon N et al. What is polypharmacy? A systematic review of definitions. BMC Geriatrics 2017
Frequently asked questions
How many medicines count as polypharmacy?
Most studies use five or more regular medicines a day. Ten or more is often called hyperpolypharmacy or excessive polypharmacy. Count prescription medicines, regular over-the-counter medicines and supplements.
Is polypharmacy always harmful?
No. "Appropriate polypharmacy" means several medicines are genuinely needed and well managed. The concern is "problematic polypharmacy", where medicines no longer help, duplicate each other or cause more harm than benefit.
Which medicines are riskiest for older adults?
Medicines that act on the brain (sleeping pills, opioids, antipsychotics, some antidepressants and antiepileptics), strongly anticholinergic drugs, blood thinners, NSAIDs, insulin and sulfonylureas cause many of the hospital admissions for side effects in older people. They are often still needed, but they deserve regular review.
What is a prescribing cascade?
It happens when a side effect of one medicine is mistaken for a new condition and treated with another medicine. Spotting it in a medication review can let the first medicine be changed instead.
What is deprescribing?
The planned, supervised reduction or stopping of medicines that may no longer help. It should always be done with a clinician, because some medicines must be tapered slowly.
How often should my medicines be reviewed?
At least once a year if you take five or more, and sooner after a hospital stay, a fall, new symptoms or when a new medicine is started.
Related calculators
Educational tool only, not a medical assessment. It does not check specific drug interactions or doses. Never stop or change a medicine on your own: some must be reduced slowly. Take your full medicine list to a pharmacist or doctor for a review.