Patterns of prescribing in primary care leading to high-dose opioid regimens: a mixed-method study.

These findings suggest that high-dose opioid regimens develop quickly in response to unknown clinical factors. An expected insidious upward drift in dose was not seen. The findings have implications for the prevention of potentially dangerous long-term, high-dose opioid prescribing. A dose of 60 mg OME or more is suggested as a useful 'red flag'.