Opioid Conversion Calculator

Opioid conversion relies on equianalgesic dose ratios, which define the doses of different opioids required to produce equivalent pain relief. This calculator uses intravenous morphine as the primary baseline reference point. The standard formula applies the specific potency ratio of the target drug and integrates a cross-tolerance reduction factor to account for incomplete cross-tolerance when rotating opioids. The mathematical structure is expressed as: Target Opioid Dose = Intravenous Morphine Baseline * Potency Multiplier * (1 - Cross Tolerance Percentage). This ensures safety margins are automatically applied during medication changes.

Consider a patient currently receiving an intravenous morphine baseline of 10 mg over a specified timeframe, with a planned cross-tolerance reduction adjustment of 25% (0.25). To determine the equivalent oral oxycodone requirement, we apply the standard oral oxycodone multiplier of 1.5. First, calculate the base conversion: 10 mg * 1.5 = 15 mg of oral oxycodone. Next, apply the cross-tolerance factor: 15 mg * (1 - 0.25) = 15 * 0.75 = 11.25 mg of oral oxycodone. This final adjusted figure provides the clinician with a safe starting point for the new regimen.

Always apply a conservative cross-tolerance reduction percentage (typically 25% to 50%) when rotating opioids to mitigate the risks of unpredicted accumulation. Monitor patients closely during the first 24 to 48 hours following any conversion for signs of excessive sedation or inadequate analgesia. Always consult institutional protocols and specialized palliative care guidelines alongside mathematical estimates.