Opioid Rotation Calculator
The formula
What the rotation dose tells you
A two-step opioid rotation: equianalgesic conversion first, then the cross-tolerance haircut second — in the wrong order it becomes an over-dose.
Calculation: New total = MED ÷ (potency of target vs 30) × (1−red); divided BD/TDS. Enter your inputs and every substitution is shown below the result.
Reading the result
Rotation success is judged at 48 h on function and side effects, not just pain scores; PRN rescue dose usage is the feedback signal.
Rules of thumb: Standard cuts 25–50 %; frail/renal patients take the larger end
Limitations and best practice
Never fully trust a rotation into methadone or transdermal fentanyl from this arithmetic — both need specialist conversion.
This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Frequently asked questions
Why keep a PRN?
Taper or rotate?
Source & methodology
Canadian Opioid Rotation Guidance; NCCN adult cancer pain.
How Opioid Rotation works — and what your result really means
You are here because you need a specific number, and you want to see how it was produced before you rely on it. Searchers land on an Opioid Rotation page for three reasons — to plan, to compare options, and to check that somebody else’s arithmetic is honest. This tool serves all three, and everything after the calculator explains the model instead of hiding it.
Most confusion about Opioid Rotation comes from mixing up the input you control with the input you merely observe. The formula treats them identically, but your decisions should not: one deserves measurement, the other deserves a defensible estimate.
In plain terms, Opioid Rotation answers the question "New daily dose?". The measurement matters because it converts a situation that feels complicated — several inputs pulling in different directions — into a single number you can act on. Within Health & Medical, Medications & Dosing is the context where this figure is quoted most often, and professionals treat it as a first-pass screen rather than a verdict.
Every figure in the prose is generated by the engine rather than written beside it — the worked example resolves to new daily dose = 34.3 on the default inputs, and the sensitivity section ranks the inputs that move the result — Current MED first, at ≈10.0 % of the headline for a ten-percent error either way in that input. Read the sections in order and you will be able to reproduce every figure by hand.
Inside the Opioid Rotation calculation: formula and every input
Here is the complete model this tool runs — New total = MED ÷ (potency of target vs 30) × (1−red); divided BD/TDS — with each input explained below. If a competitor’s page gives you a different answer from the same inputs, this is the text that settles which of you is right.
Current MED (mg/day) (example value 205) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Use the value as of today, not as of the last time you looked — time fields drift silently.
Target opioid (example value Oral hydromorphone) is a branching choice rather than a figure you measure; the per-option effects are computed below. This input feeds the formula directly; a defensible figure here is worth more than false precision anywhere else.
Reduction for tolerance (example value 33) is a measured number in the unit named by the label; the formula does not convert for you. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
Doses per day (example value 6) is a measured number in the unit named by the label; the formula does not convert for you. If the period is partial, decide whether you mean elapsed or planned time and keep that meaning across every field.
What each “Target opioid” choice actually does: Oral hydromorphone → 34.3 · Oral oxycodone → 91.6 · Oral morphine → 137.4 · Transdermal fentanyl (µg/h ≈ MED ÷ 2.5) → 54.9 — each value above is the model’s own output for that option, so the choice can be made on evidence rather than on what a category feels like it means.
A fully worked Opioid Rotation example
The tool prints its own working; this is the same arithmetic on the example values, reproduced so you can follow it by hand. Starting figures: Current MED (mg/day), Target opioid, Reduction for tolerance, Doses per day. Run to the end, the new daily dose resolves to 34.3 — Rotating 205 MED with a 33 % cut targets ~34.3 mg/day of the new opioid — 5.7 mg × 6 — and the breakthrough plan (10–15 % PRN) is the part that makes rotation survivable on the bands this tool uses.
- Ratio target/30 = 0.25
- 205 × 0.25 × 0.67 = 34.3
- ÷ 6 doses = 5.7 mg each
Raw conversion — 51.3 mg/day. If your inputs change, this is usually the first companion figure to move.
Per dose — 5.7 mg. If your inputs change, this is usually the first companion figure to move.
PRN reserve — 4.1 mg/day. This is the number experienced users quote when the headline alone would mislead.
Fentanyl caution — oral rotation. If your inputs change, this is usually the first companion figure to move.
Overwrite any input above and every line of this example updates with it — the substitution is live, not a screenshot of somebody else’s numbers.
Scenario table: Opioid Rotation at ±10 % and ±20 % of the key input
Single-point answers invite false confidence, so the same engine was run across a band around the input that matters most here. Each row is a full recalculation of Opioid Rotation, not an interpolation.
| Current MED setting | New daily dose |
|---|---|
| 80 % of the example value | 27.5 |
| 90 % of the example value | 30.9 |
| example inputs | 34.3 |
| 110 % of the example value | 37.8 |
| 120 % of the example value | 41.2 |
That spread — 27.5 at the low end, 41.2 at the high — is what a careful read of Opioid Rotation looks like: a band you can state out loud, with the reason for each edge. Reproduce it in the form above by editing Current MED alone; the substitution steps will follow your figures exactly.
What actually moves your Opioid Rotation
Generic advice says “it depends on your inputs”; this section says exactly how much. Each field was perturbed by ±10 % in isolation and the new daily dose recomputed, so the ranking below is measured rather than asserted. It is the fastest honest answer to “what matters most in Opioid Rotation?” — and it is specific to these defaults, because sensitivity moves with the starting point.
- Current MED +10 % → Opioid Rotation = 37.8 · −10 % → 30.9 (the new daily dose shifts ≈10.0 %)
- Reduction for tolerance +10 % → Opioid Rotation = 32.6 · −10 % → 36.0 (the new daily dose shifts ≈4.9 %)
Current MED is the dominant lever here: ten percent either way moves the result by about 10.0 %, from 30.9 to 37.8. Measure that input from a document rather than from memory, and treat Reduction for tolerance as the second priority (≈4.9 % per ten percent). The rest of the inputs earn only a rounding-error of attention, and that asymmetry is the practical payoff of measuring rather than asserting.
What an Opioid Rotation of 34.3 means in practice
Nobody acts on a bare figure — they act on a figure with a comparison attached. The verdict attached to the default calculation — “Rotating 205 MED with a 33 % cut targets ~34.3 mg/day of the new opioid — 5.7 mg × 6 — and the breakthrough plan (10–15 % PRN) is the part that makes rotation survivable” — is one band on a ladder your own figure may sit somewhere else on. Before treating the band as fact, note its width: ten percent either way on Current MED already spans 30.9 to 37.8. The practical reading rules: read the band as a starting hypothesis, then test it: change the two dominant inputs by ten percent and see whether the verdict survives. Verdicts that survive stress are the ones worth acting on.
Where Opioid Rotation sits next to similar measures: this tool answers “how much is the Opioid Rotation”, while the related calculators answer “what do I do about it”. Reading the result alone tends to over-weight a single snapshot; pairing it with the companion tools above turns the number into a decision.
Common mistakes with Opioid Rotation (and the fix)
Never fully trust a rotation into methadone or transdermal fentanyl from this arithmetic — both need specialist conversion. This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Using stale inputs. Opioid Rotation is only as current as the numbers behind it — an estimate carried over from a previous season, rate table or report quietly biases every output. Re-measure the inputs first; that single habit fixes more bad Opioid Rotation figures than any formula change.
This model has its own particular trap: Current MED carries ≈10.0 % of the response per ten percent of error, so effort spent elsewhere is largely decorative.
A final trap is presentation: reporting Opioid Rotation to more decimal places than the inputs support. The tool prints what the arithmetic gives; you should quote only what your least precise field justifies.
Opioid Rotation verification checklist
- State, in one sentence, which convention each rate, unit or period in the form is using.
- Compare the output against one published benchmark or a colleague’s independent estimate.
- Put Current MED under a magnifier; the sensitivity table above is the reason why.
- Re-run the calculation with a ±10 % stress on the two most sensitive inputs.
- Check that every field the formula needs actually arrived from a document, not from recollection.
- Run the ±10 % stress on the top two levers and check that your conclusion survives both.
A routine for decision-grade Opioid Rotation
The tool does the arithmetic; the routine below is what makes the arithmetic trustworthy. Five steps, a minute total — and afterwards you will know not just what the number is, but which assumption produced it.
Step 1 — start from evidence. The inputs behind Opioid Rotation are current med (mg/day), target opioid, reduction for tolerance, doses per day. Write them down with their source next to each one; if you cannot name where a figure came from, that is the input most likely to be wrong. Precision is a promise you make about your data; make sure your inputs can keep it.
Step 2 — start from the case you can defend. Enter pessimistic-but-honest figures first; the optimistic run is a ceiling, not a plan. A conclusion that holds on conservative inputs holds everywhere. One decimal place more than your data supports is one decimal place of fiction.
Step 3 — play with the inputs on purpose. Ten percent up, ten percent down, one field at a time. Within a few minutes you will know this calculation better than most people who quote its results. Suspiciously tidy answers deserve the same scrutiny as untidy ones.
Step 4 — run the scenario trio. Expected, pessimistic, optimistic. The gap between pessimistic and expected is the number to plan against; the optimistic result is useful only as a ceiling. Half of a good calculation is knowing which input you would hate to be wrong about.
Step 5 — record the context, not just the number. Note today’s date and the inputs alongside the 34.3 output. Six months from now the context is what turns this figure into a trend. If the verdict changes with a ten-percent nudge, report the nudge alongside the number.
The real-world conversations Opioid Rotation settles
Health & Medical arguments end at arithmetic or they do not end. Opioid Rotation is the arithmetic: 34.3 on the example inputs, reproducible by anyone who types the same numbers. The point of transparency is that a reader can disagree with a specific line rather than with you.
The audience for this page is people who need one trustworthy number before their next decision. In professional Medications & Dosing practice the pattern is always the same — screen with Opioid Rotation, then invest slow analysis only in whatever survives the screen. When two sources disagree, it is almost never the arithmetic that differs.
There is a personal-administration use people overlook: periodic self-checking. Opioid Rotation quietly drifts as life changes — rates move, bodies change, costs compound — and re-running it a few times a year catches drift while correction is still cheap. One decimal place more than your data supports is one decimal place of fiction.
People also ask about Opioid Rotation
What affects Opioid Rotation the most?
Measured on this engine, Current MED is the dominant lever: moving it ±10 % shifts the new daily dose across 30.9 to 37.8 — about 10.0 % of the headline, with Reduction for tolerance next at ≈4.9 %. The ranked list in the sensitivity section is computed live, not asserted from a template.
Which matters more: reduction for tolerance or current med?
For Opioid Rotation, Current MED wins the head-to-head (≈10.0 % against ≈4.9 % per ten-percent change). Knowing which input dominates is the difference between careful work and merely slow work.
How much does the “Target opioid” choice change the answer?
The spread is not cosmetic: this choice alone takes Opioid Rotation from 34.3 to 137.4 with every other input frozen, which is more influence than most of the numeric fields on this page can claim.
What is a typical Opioid Rotation?
With the example inputs on this page the result is 34.3, labelled “Rotating 205 MED with a 33 % cut targets ~34.3 mg/day of the new opioid — 5.7 mg × 6 — and the breakthrough plan (10–15 % PRN) is the part that makes rotation survivable”. “Typical” varies with situation, which is why every result here ships with its verdict band and its sensitivity list: they turn one figure into a range you can locate yourself inside.
How do I calculate Opioid Rotation by hand?
Use the stated model — New total = MED ÷ (potency of target vs 30) × (1−red); divided BD/TDS — and substitute in the order the tool prints (it starts from Ratio target/30 = 0.25). On the example inputs the hand route lands on 34.3, exactly what the calculator shows. A spreadsheet reproduces it in two or three cells; doing it once by hand is what makes the automated answer trustworthy.
What happens to Opioid Rotation if current med changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the new daily dose goes across 30.9 to 37.8, a swing of roughly 10.0 % around the 34.3 baseline. That ratio is the practical definition of how much this input matters.
Is the Opioid Rotation result of 34.3 good or bad?
Good and bad are comparisons, so the honest test is three questions: where does your own Opioid Rotation sit against the 34.3 reference above, how far would a plausible input error move it (≈10.0 % per ten percent on Current MED), and what does the alternative option compute to?
Can Opioid Rotation be negative or empty?
Yes, and that is informative rather than broken: a negative Opioid Rotation usually means the inputs encode an outflow or a shortfall, and the verdict band above labels exactly that situation instead of hiding it.
What affects Opioid Rotation the most?
Sensitivity depends on where you start, but the inputs Current MED (mg/day) and Target opioid typically move Opioid Rotation further than the rest because they enter the formula multiplicatively. If you can only measure two things well, measure those and hold the others at conservative defaults.
Why keep a PRN?
Incomplete cross-tolerance is patient-specific; the PRN reveals the true position between the raw and reduced dose.
Taper or rotate?
If pain is improving on the old opioid, rotate with the smaller cut; if not, rotate with the bigger cut and reassess.
Do I need an account to use this Opioid Rotation calculator?
No, and no data leaves the tab. The engine runs in the page itself, which is why the worked example, the bands and the sensitivity ranking all respond instantly to your keystrokes.
Glossary for Opioid Rotation
- Raw conversion
- 51.3 mg/day in the default Opioid Rotation calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Per dose
- 5.7 mg for the Opioid Rotation worked case; it sits next to the main result because it carries context the headline leaves out.
- PRN reserve
- 4.1 mg/day for the Opioid Rotation worked case; it sits next to the main result because it carries context the headline leaves out.
- New daily dose
- The primary output of this tool: 34.3 for the default inputs, computed exactly from New total = MED ÷ (potency of target vs 30) × (1−red); divided BD/TDS.
- Worked example
- The step-by-step substitution printed above, so the arithmetic can be re-derived by hand or in a spreadsheet.
- Verdict band
- The interpretation attached to a result (“Rotating 205 MED with a 33 % cut targets ~34.3 mg/day of the new opioid — 5.7 mg × 6 — and the breakthrough plan (10–15 % PRN) is the part that makes rotation survivable” on these inputs), which turns a bare number into a position on a scale.
- Sensitivity (±10 %)
- How far the Opioid Rotation moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Method, sources and what this tool cannot tell you
Everything above runs on one stated formula, applied without hidden coefficients: New total = MED ÷ (potency of target vs 30) × (1−red); divided BD/TDS. Source of record: Canadian Opioid Rotation Guidance; NCCN adult cancer pain. Where a professional version of this calculation differs, it differs in inputs and jurisdiction-specific coefficients, not in the algebra — which is why re-checking your inputs beats hunting for a second calculator.
Treat the output as a precise answer to the question you typed: exact arithmetic, transparent formula, published source, no hidden rounding. The design constraint was set by usefulness rather than by comfort: an estimate you can interrogate beats an answer you have to trust.
Turning this Opioid Rotation into a decision
Save the number together with its inputs and today’s date; an Opioid Rotation figure without context is unusable the moment an input changes.
This page was written for people who need one trustworthy number before their next decision, and the promise is that nothing above required trust. Bookmark the tool, re-run it whenever an input moves by more than a few percent, and keep the date with the number.