Continuing Opioids

Opioid Rotation


Although some patients with moderate to severe chronic pain may achieve sufficient analgesia on one type of opioid, many others may suffer from adverse events, tolerance, or insufficient analgesia. For these patients, opioid rotation/switching has become a widely used clinical practice.

Opioid Dose Calculator

Important Safety Notes:
  • Dose calculator tables are useful tools, but they have been found to have major shortcomings. These tables may not be generalizable to all patients, especially given the recently discovered genetic variations in opioid receptors

Source:  Molecular Insights Into μ Opioid Pharmacology: From the Clinic to the Bench

  • In addition, research has shown that many patients have incomplete cross-tolerance when switched from one opioid to another

Source: Pasternak, GW. “Molecular insights into µ opioid pharmacology: from the clinic to the bench.” Clinical Pain Journal. 2010;26(10):S3-S9.

  • Methadone is particularly challenging to convert to/from due to its long and variable half-life and shorter analgesic effect.


For More Information:



Pereira J et al. Equianalgesic dose ratios, a critical review and proposals for long-term dosing. J Pain Symptom Manage. 2011 Aug; 22(2):672-87.

Webster LR, Fine PG. Review and critique of opioid rotation practices and associated risks of toxicity. Pain Med. 2012 Apr;13(4):562-70.