MS Contin 15mg XR to Hydrocodone Conversion
Based on NCCN guidelines, hydrocodone is approximately equipotent with oral morphine (1:1 ratio), so MS Contin 15mg XR converts to approximately 15mg of hydrocodone daily, which would typically be dosed as hydrocodone 5mg three times daily or 7.5mg twice daily. 1
Conversion Calculation
- The NCCN Clinical Practice Guidelines state that hydrocodone may be approximately equipotent with oral morphine, though this equivalence data is not fully substantiated. 1
- MS Contin 15mg XR provides 15mg of morphine over 24 hours 2, 3
- Using the 1:1 morphine-to-hydrocodone conversion ratio, this equals approximately 15mg of hydrocodone daily 1
Practical Dosing Recommendations
- Hydrocodone is available only in immediate-release formulations combined with acetaminophen or ibuprofen, requiring multiple daily doses. 1
- Typical dosing options include:
- Hydrocodone ER preparations exist but are less commonly used 1
Critical Safety Considerations
- When rotating opioids, reduce the calculated equivalent dose by 25-50% to account for incomplete cross-tolerance and individual pharmacokinetic variability. 4
- This means starting with hydrocodone 7.5-11mg daily (rather than the full 15mg equivalent) would be safer 4
- The CDC explicitly warns against using calculated morphine milligram equivalents (MME) directly for conversions without dose reduction. 4
Important Clinical Caveats
- Hydrocodone should be used with caution in patients with fluctuating renal function due to potential accumulation of renally cleared metabolites that may cause neurologic toxicity. 1
- Clinical experience suggests hydrocodone is best used as a mild, initial-use opioid, and effective doses may vary significantly between patients 1
- Reassessment within 1-4 days is necessary to adjust dosing based on pain control and adverse effects. 4
- Provide immediate-release opioid for breakthrough pain during the conversion period 4
Alternative Consideration
- If extended-release formulation is preferred, consider converting to a different long-acting opioid (such as oxycodone ER) rather than hydrocodone, as hydrocodone IR formulations require more frequent dosing 1