Estimate dose-weighted CNS medication burden, review the contribution of each drug class, and identify regimens that reach the published 3-SDD research threshold.
For each non-opioid medication, the entered daily dose is divided by the legacy index denominator. Individual SDDs are then summed across the medication regimen.
The public build defaults to the legacy GlobalRPh opioid coefficient behavior to preserve continuity with the existing calculator. The coefficient profile is isolated in config.php/data.php for expert-panel revision.
Leave medications blank when they are not part of the regimen. Use the total amount administered or prescribed per day, not a single dose.
These are the historical SDD index constants used to reproduce the published/legacy calculation. They are not 2026 starting doses, target doses, maximum doses, or prescribing recommendations. A value of 1 SDD means the entered daily exposure equals the listed index denominator, or for opioids, produces 10 MME/day under the active coefficient profile.
| Medication | Input unit | Legacy factor used | Exposure equal to 1 SDD | CDC 2022 factor* | SDD formula |
|---|---|---|---|---|---|
| CodeinePO | mg/day | 0.15 | 66.667 mg/day | 0.15 | (daily exposure × factor) ÷ 10 MME |
| FentanylTransdermal | mcg/hr | 4.1667 | 2.4 mcg/hr | 2.4 | (daily exposure × factor) ÷ 10 MME |
| HydrocodonePO | mg/day | 1.3 | 7.692 mg/day | 1 | (daily exposure × factor) ÷ 10 MME |
| HydromorphonePO | mg/day | 5 | 2 mg/day | 5 | (daily exposure × factor) ÷ 10 MME |
| MethadonePO | mg/day | 4 | 2.5 mg/day | 4.7 | (daily exposure × factor) ÷ 10 MME |
| MorphinePO | mg/day | 1 | 10 mg/day | 1 | (daily exposure × factor) ÷ 10 MME |
| OxycodonePO | mg/day | 1.5 | 6.667 mg/day | 1.5 | (daily exposure × factor) ÷ 10 MME |
| TramadolPO | mg/day | 0.2 | 50 mg/day | 0.2 | (daily exposure × factor) ÷ 10 MME |
*CDC 2022 factors are shown for transparency and sensitivity review only. They are not used in the public SDD result because substituting them would alter the historical index. The active public profile is: Legacy GlobalRPh computational opioid profile.
| Medication | Subclass | Historical SDD denominator | 1 SDD equals | Calculation |
|---|---|---|---|---|
| Amitriptyline | Tricyclic antidepressants | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Clomipramine | Tricyclic antidepressants | 25 mg/day | 25 mg/day | daily dose ÷ 25 |
| Desipramine | Tricyclic antidepressants | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Doxepin | Tricyclic antidepressants | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Nortriptyline | Tricyclic antidepressants | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Citalopram | SSRIs | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Escitalopram | SSRIs | 5 mg/day | 5 mg/day | daily dose ÷ 5 |
| Fluoxetine | SSRIs | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Fluvoxamine | SSRIs | 50 mg/day | 50 mg/day | daily dose ÷ 50 |
| Paroxetine | SSRIs | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Sertraline | SSRIs | 50 mg/day | 50 mg/day | daily dose ÷ 50 |
| Desvenlafaxine | SNRIs | 75 mg/day | 75 mg/day | daily dose ÷ 75 |
| Duloxetine | SNRIs | 40 mg/day | 40 mg/day | daily dose ÷ 40 |
| Milnacipran | SNRIs | 50 mg/day | 50 mg/day | daily dose ÷ 50 |
| Venlafaxine | SNRIs | 75 mg/day | 75 mg/day | daily dose ÷ 75 |
| Medication | Subclass | Historical SDD denominator | 1 SDD equals | Calculation |
|---|---|---|---|---|
| Carbamazepine | Antiseizure / Antiepileptic Medications | 600 mg/day | 600 mg/day | daily dose ÷ 600 |
| Gabapentin | Antiseizure / Antiepileptic Medications | 900 mg/day | 900 mg/day | daily dose ÷ 900 |
| Lamotrigine | Antiseizure / Antiepileptic Medications | 150 mg/day | 150 mg/day | daily dose ÷ 150 |
| Levetiracetam | Antiseizure / Antiepileptic Medications | 1000 mg/day | 1000 mg/day | daily dose ÷ 1000 |
| Oxcarbazepine | Antiseizure / Antiepileptic Medications | 900 mg/day | 900 mg/day | daily dose ÷ 900 |
| Phenytoin | Antiseizure / Antiepileptic Medications | 300 mg/day | 300 mg/day | daily dose ÷ 300 |
| Pregabalin | Antiseizure / Antiepileptic Medications | 150 mg/day | 150 mg/day | daily dose ÷ 150 |
| Primidone | Antiseizure / Antiepileptic Medications | 750 mg/day | 750 mg/day | daily dose ÷ 750 |
| Topiramate | Antiseizure / Antiepileptic Medications | 100 mg/day | 100 mg/day | daily dose ÷ 100 |
| Valproic acid / divalproex | Antiseizure / Antiepileptic Medications | 1000 mg/day | 1000 mg/day | daily dose ÷ 1000 |
| Zonisamide | Antiseizure / Antiepileptic Medications | 100 mg/day | 100 mg/day | daily dose ÷ 100 |
| Medication | Subclass | Historical SDD denominator | 1 SDD equals | Calculation |
|---|---|---|---|---|
| Chlorpromazine | Conventional / first-generation | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Fluphenazine | Conventional / first-generation | 0.5 mg/day | 0.5 mg/day | daily dose ÷ 0.5 |
| Haloperidol | Conventional / first-generation | 0.5 mg/day | 0.5 mg/day | daily dose ÷ 0.5 |
| Perphenazine | Conventional / first-generation | 2 mg/day | 2 mg/day | daily dose ÷ 2 |
| Thioridazine | Conventional / first-generation | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Thiothixene | Conventional / first-generation | 1 mg/day | 1 mg/day | daily dose ÷ 1 |
| Trifluoperazine | Conventional / first-generation | 1 mg/day | 1 mg/day | daily dose ÷ 1 |
| Aripiprazole | Atypical / second-generation | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Asenapine | Atypical / second-generation | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Olanzapine | Atypical / second-generation | 5 mg/day | 5 mg/day | daily dose ÷ 5 |
| Quetiapine | Atypical / second-generation | 50 mg/day | 50 mg/day | daily dose ÷ 50 |
| Risperidone | Atypical / second-generation | 2 mg/day | 2 mg/day | daily dose ÷ 2 |
| Ziprasidone | Atypical / second-generation | 20 mg/day | 20 mg/day | daily dose ÷ 20 |
| Medication | Subclass | Historical SDD denominator | 1 SDD equals | Calculation |
|---|---|---|---|---|
| Alprazolam | Benzodiazepines & Z-Drugs | 0.25 mg/day | 0.25 mg/day | daily dose ÷ 0.25 |
| Chlordiazepoxide | Benzodiazepines & Z-Drugs | 5 mg/day | 5 mg/day | daily dose ÷ 5 |
| Clonazepam | Benzodiazepines & Z-Drugs | 0.25 mg/day | 0.25 mg/day | daily dose ÷ 0.25 |
| Clorazepate | Benzodiazepines & Z-Drugs | 3.75 mg/day | 3.75 mg/day | daily dose ÷ 3.75 |
| Diazepam | Benzodiazepines & Z-Drugs | 2 mg/day | 2 mg/day | daily dose ÷ 2 |
| Estazolam | Benzodiazepines & Z-Drugs | 0.5 mg/day | 0.5 mg/day | daily dose ÷ 0.5 |
| Eszopiclone | Benzodiazepines & Z-Drugs | 1 mg/day | 1 mg/day | daily dose ÷ 1 |
| Flurazepam | Benzodiazepines & Z-Drugs | 15 mg/day | 15 mg/day | daily dose ÷ 15 |
| Lorazepam | Benzodiazepines & Z-Drugs | 1 mg/day | 1 mg/day | daily dose ÷ 1 |
| Oxazepam | Benzodiazepines & Z-Drugs | 10 mg/day | 10 mg/day | daily dose ÷ 10 |
| Quazepam | Benzodiazepines & Z-Drugs | 7.5 mg/day | 7.5 mg/day | daily dose ÷ 7.5 |
| Temazepam | Benzodiazepines & Z-Drugs | 7.5 mg/day | 7.5 mg/day | daily dose ÷ 7.5 |
| Triazolam | Benzodiazepines & Z-Drugs | 0.13 mg/day | 0.13 mg/day | daily dose ÷ 0.13 |
| Zaleplon | Benzodiazepines & Z-Drugs | 2.5 mg/day | 2.5 mg/day | daily dose ÷ 2.5 |
| Zolpidem | Benzodiazepines & Z-Drugs | 2.5 mg/day | 2.5 mg/day | daily dose ÷ 2.5 |
The threshold is best treated as a medication-review signal. In the 2017 U.S. nursing-home study, residents with a recent fall who had approximately 3 or more CNS SDDs had higher adjusted odds of a serious fall than residents with no CNS medication exposure. A later VA Community Living Center analysis found a similar association with recurrent serious falls.
These are observational associations. The calculator does not estimate an individual patient's absolute probability of falling, and a result below 3 does not establish safety. Likewise, getting a score below 3 is not proven to prevent a fall in a given patient.
CDC's 2026 data describe falls as the leading cause of injury among adults age 65 years and older. More than 14 million U.S. older adults, approximately 1 in 4, report a fall each year. About 37% of those reporting a fall describe an injury requiring medical treatment or restricting activity for at least a day.
Medication burden is only one modifiable contributor. Mobility and balance, orthostatic blood pressure, vision, cognition, footwear, environmental hazards, alcohol or other sedating substances, acute illness, and prior falls remain important.
As of this calculator's August 2026 evidence review, the American Geriatrics Society continues to list the 2023 Updated AGS Beers Criteria® as its current Beers guideline. In 2025, AGS published a companion resource describing alternative treatments for selected Beers medications. The Beers Criteria and this SDD calculator answer different questions: Beers identifies potentially inappropriate medications, drug-disease concerns, drug-drug interactions, and renal considerations; SDD quantifies dose-weighted exposure within a specific historical CNS index.
| Current geriatric medication-safety issue | Relevant guidance | How this calculator handles it |
|---|---|---|
| ≥3 CNS-active medications | Beers recommends avoiding concurrent use of 3 or more CNS-active agents when possible because of increased falls/fracture risk. Classes include antiseizure medications (including gabapentinoids), antidepressants, antipsychotics, benzodiazepines, Z-drugs, opioids, and skeletal muscle relaxants. | Reported as a separate medication-count flag; it does not alter SDD. |
| History of falls or fractures | Beers highlights anticholinergics, selected antidepressants, antiseizure medications, antipsychotics, benzodiazepines, Z-drugs, and opioids. When one must be used, reducing other CNS-active medications and implementing additional fall-reduction strategies should be considered. | The SDD result is framed as one component of a comprehensive fall-risk review. |
| Opioid + benzodiazepine | Beers recommends avoiding the combination because of overdose and adverse-event risk. | Both agents contribute to burden; the combination should trigger an independent interaction review. |
| Opioid + gabapentin/pregabalin | Beers recommends avoiding the combination except in limited circumstances such as transition from opioids or use of gabapentinoids to reduce opioid dose; severe sedation-related events, including respiratory depression and death, are a concern. | The drugs contribute separately to SDD. The score itself does not quantify respiratory-depression risk. |
| Renal function | Beers calls for dose reduction of gabapentin and pregabalin when CrCl is below 60 mL/min and includes additional renal guidance for levetiracetam, tramadol, duloxetine, and other drugs. | Renal function is not used to automatically change SDD. Verify the clinically appropriate dose separately. |
| SIADH / hyponatremia | Selected antidepressants, carbamazepine/oxcarbazepine, antipsychotics, diuretics, and tramadol are among Beers medications to use with caution in relation to SIADH/hyponatremia; sodium monitoring may be appropriate when starting or changing doses. | This is a parallel safety issue and is not represented numerically in SDD. |
| Strongly anticholinergic antidepressants | The 2023 Beers Criteria lists amitriptyline, clomipramine, desipramine, nortriptyline, paroxetine, and doxepin above 6 mg/day among antidepressants with strong anticholinergic activity to avoid in most older adults because of anticholinergic effects, sedation, and orthostatic hypotension. Low-dose doxepin at 6 mg/day or less is treated differently in Beers. | These agents may have a low or moderate SDD and still meet a separate Beers criterion. SDD must not be used to override the drug-specific Beers recommendation. |
| Benzodiazepines and Z-drugs | Beers generally recommends avoiding benzodiazepines in older adults because of increased sensitivity and risks that include cognitive impairment, delirium, falls, fractures, and motor-vehicle crashes; nonbenzodiazepine benzodiazepine-receptor agonist hypnotics have similar adverse-event concerns with limited sleep benefit. | The historical SDD quantifies dose burden only. It does not convert a lower dose into a declaration that chronic use is appropriate. |
| Antipsychotics in dementia or delirium | Beers recommends avoiding antipsychotics for behavioral problems of dementia or delirium unless nonpharmacologic options have failed or are not possible and the patient is threatening substantial harm to self or others; periodic attempts to reduce or discontinue therapy should be considered when clinically appropriate. | SDD reports antipsychotic exposure but does not determine indication appropriateness or substitute for behavioral, diagnostic, or deprescribing review. |
Beers criteria are intended to support, not replace, individualized clinical judgment. They are not a list of medications that are always inappropriate.
A 2026 analysis of 211,783 long-stay U.S. nursing-home residents with Fee-for-Service Medicare found 23.2% met a definition of CNS-active polypharmacy: at least 3 medications for more than 30 days across antidepressants, antiseizure medications, antipsychotics, benzodiazepines, Z-drugs, opioids, and skeletal muscle relaxants. Gabapentin was the most frequently prescribed individual medication involved.
The most common class combination was one antidepressant, one antiseizure medication, and one antipsychotic. This reinforces why the medication-count screen is useful alongside SDD rather than being substituted for it.
A 2024 cluster-randomized trial of CNS-active medication deprescribing in community-dwelling older adults did not significantly reduce medically treated falls compared with usual care. A 2026 systematic review and meta-analysis similarly found that fall reduction from psychotropic-targeting deprescribing was not clearly demonstrated across all settings; effects appeared dependent on setting and implementation fidelity.
The practical implication is not “do not deprescribe.” It is that deprescribing should be indication-specific, patient-centered, and monitored. Abrupt discontinuation can itself be hazardous for benzodiazepines, antiseizure medications, opioids, and other agents.
CDC's STEADI-Rx resources emphasize a pharmacist-clinician workflow of screening for fall risk, reviewing medications, communicating findings, and coordinating intervention. This calculator can support the medication-review component, but it should not replace functional testing, orthostatic assessment, or the rest of a structured falls evaluation.
The historical SDD algorithm and modern geriatric medication-safety guidance are related but are not interchangeable. The table below makes the differences explicit so clinicians can see which elements are historical index constants, which are software defects, and which represent newer evidence that should remain a parallel clinical signal unless a TEP approves and validates a new method version.
| Domain | Legacy implementation | Current evidence / guidance | Current calculator handling |
|---|---|---|---|
| SDD threshold | SDD ≥3 was presented as indicating high fall risk. | Published nursing-home studies support an association between higher CNS dose burden and serious/recurrent serious falls, but the score is not an individual absolute-risk model and observational evidence does not prove that lowering a patient's score below 3 prevents a fall. | Preserve the ≥3 research threshold but label it as a medication-review signal rather than a diagnosis or treatment mandate. |
| Non-opioid denominators | Listed as “minimum effective geriatric daily doses.” | These values are part of the historical index definition. Modern product labeling, Beers recommendations, renal dosing, or usual starting doses answer different questions and cannot be substituted without changing the index. | Retain them as historical SDD constants, display them transparently, and explicitly state that they are not 2026 prescribing recommendations. |
| Drug universe | 62 indexed medications across opioids, antidepressants, antiseizure medications, antipsychotics, and benzodiazepine-receptor agonists. | The Beers CNS-polypharmacy framework is broader and includes classes such as skeletal muscle relaxants and CNS-active agents that were not assigned historical SDD denominators. | Do not fabricate SDD values for unvalidated drugs. Count relevant additional CNS-active medications in the separate polypharmacy screen. |
| Drug-specific Beers concerns | A drug's contribution is driven mainly by dose divided by its historical denominator. | Some indexed drugs carry drug-specific Beers recommendations that are not proportional to SDD. Examples include strongly anticholinergic antidepressants, benzodiazepines/Z-drugs, and antipsychotics in dementia or delirium. | Display Beers guidance separately. A low SDD never cancels a drug-specific PIM, interaction, disease, renal, or monitoring concern. |
| ≥3 CNS-active medications | No separate medication-count rule. | The 2023 AGS Beers Criteria recommends avoiding concurrent use of ≥3 CNS-active drugs from specified classes when possible because of increased falls/fracture risk. | Report a separate Beers-style CNS medication-count flag; do not add points to SDD. |
| Renal function and interactions | Not incorporated into the numerical score. | Beers provides renal-function guidance and flags clinically important combinations such as opioid + benzodiazepine and opioid + gabapentin/pregabalin. | Keep these as parallel safety checks. They should not be inferred from a single summed SDD value. |
| Eszopiclone | The Perl code calculated the individual eszopiclone SDD but omitted it from the BZRA subtotal and final SDD. | This is a coding defect, not an evidence update. | Corrected in v2.x and disclosed in version history. |
| Transdermal fentanyl | The Perl calculation used an effective MME factor of approximately 4.1667, while the legacy explanatory text displayed 7.2. | CDC 2022 lists 2.4 MME per mcg/hr for transdermal fentanyl. Replacing the historical factor would materially change SDD. | Preserve the actual legacy Perl factor in the public legacy-comparable profile; show CDC 2022 as a sensitivity comparator pending TEP review. |
| Opioid | Actual legacy Perl factor | Legacy page display | CDC 2022 factor | Status |
|---|---|---|---|---|
| Codeine | 0.15 | 0.15 | 0.15 | Same |
| Fentanyl transdermal (mcg/hr) | 4.1667 | 7.2 | 2.4 | Legacy internal mismatch; current CDC also differs |
| Hydrocodone | 1.3 | 1.3 | 1.0 | Differs |
| Hydromorphone | 5.0 | 5.0 | 5.0 | Same |
| Methadone | 4.0 | 4.0 | 4.7 | Differs |
| Morphine | 1.0 | 1.0 | 1.0 | Same |
| Oxycodone | 1.5 | 1.5 | 1.5 | Same |
| Tramadol | 0.2 | 0.2 | 0.2 | Same |
CDC MME factors are estimates for standardizing opioid dosage and are not direct equianalgesic conversion instructions. In this calculator, the CDC column is shown for transparency only and does not alter the default historical SDD result.
STOPP/START version 3, published in 2023, expanded to 190 criteria, including a substantially larger set of CNS and fall-risk-increasing-drug criteria. Its authors specifically emphasize that electronic tools can improve identification of potentially inappropriate prescribing but still require trained clinical interpretation. This is consistent with how SDD should be used: as structured decision support, not an autonomous prescribing rule.
The legacy GlobalRPh calculator and its accompanying explanatory table are not fully internally consistent for transdermal fentanyl, and several opioid conversion factors differ from the CDC 2022 MME table. The rebuilt calculator therefore keeps the legacy computational behavior as the default profile instead of silently changing historical calculator output. A CDC 2022 sensitivity profile is included for TEP evaluation, but activating it changes the opioid contribution to SDD and should be treated as a methodological revision rather than a routine software update. MME factors in this tool are used only to standardize exposure for the burden index; they should not be used to calculate a dose when switching from one opioid to another.
The 2026 rebuild was intentionally structured so a Technical Expert Panel can review methodology without rewriting the application. Software defects can be corrected while historical coefficients, proposed new drugs/classes, opioid-factor changes, PRN exposure rules, validation endpoints, and future thresholds remain version-controlled scientific decisions.
