Calculator (Transdermal Fentanyl ↔ Oral Morphine Equivalent)
Use this tool to estimate equivalence only. It is not a prescription tool.
Formula used here: 1 mcg/hour transdermal fentanyl ≈ 2.4 mg oral morphine equivalent per day.
What this fentanilo a morfina calculator does
This page estimates opioid equivalence between transdermal fentanyl (fentanilo patch) and oral morphine using a commonly cited conversion factor. In practical terms, it helps you translate one regimen into an approximate oral morphine equivalent (MME/day), or reverse that estimate back into a patch strength.
The main goal is clarity: many people search for “fentanilo a morfina calculator” when they want a quick conversion reference. This tool provides that estimate in one place and reminds you about critical limitations.
Important limitations before using any conversion
- Applies to transdermal fentanyl patch, not IV fentanyl or transmucosal products.
- Provides an equianalgesic estimate, not a final or safe starting prescription.
- Patient-specific factors can change real potency: age, frailty, liver function, renal function, and opioid tolerance.
- Cross-tolerance is incomplete; simple equal-dose switching can cause overdose or withdrawal.
- Always follow institutional protocols and specialist guidance for actual clinical decisions.
How the formula works
Morphine mg/day = Fentanyl mcg/hour × 2.4
Fentanyl mcg/hour = Morphine mg/day ÷ 2.4
Example: a 25 mcg/hour patch corresponds to roughly 60 mg/day oral morphine equivalent (25 × 2.4 = 60). In reverse, 120 mg/day oral morphine equivalent corresponds to roughly 50 mcg/hour fentanyl patch (120 ÷ 2.4 = 50).
Why opioid conversion is never “one size fits all”
1) Individual response varies
Two patients on the same calculated equivalent may experience very different analgesia and side effects. Genetics, concurrent medications, and organ function all matter.
2) Route and formulation matter
Fentanyl patch delivery is continuous and depends on skin absorption. Heat exposure, fever, or damaged skin can alter drug delivery. That means real-world exposure may differ from table-based math.
3) Timing of effect matters
Patch onset and offset are delayed compared with immediate oral dosing. Conversion should account for overlap, breakthrough pain planning, and close monitoring.
Best-practice checklist when reviewing conversions
- Confirm opioid tolerance status.
- Confirm exact current regimen and total daily opioid use.
- Use one standardized equianalgesic reference.
- Apply clinical adjustment based on risk profile.
- Arrange follow-up and monitor sedation, respiratory status, and pain control.
FAQ
Is this a prescribing calculator?
No. It is an educational equivalence calculator.
Does it calculate IV fentanyl to morphine?
No. This page is for transdermal fentanyl patch conversions only.
Can I use this for self-medication?
No. Opioid changes should be managed by a licensed clinician due to overdose risk.
Final note
A “fentanilo a morfina calculator” is useful for understanding relative potency, but safe opioid care depends on far more than math. Treat this as a learning and communication aid, not a standalone treatment decision tool.