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

BACKGROUND: There are concerns about continuing increases in the number of patients prescribed long-term opioids and the prescribing of 'strong' opioids for chronic pain. Little is known about patients who are prescribed these long-term, high-dose drugs. AIM: To understand patterns of opioid prescribing that lead to long-term, high-dose use. DESIGN & SETTING: A mixed-method study of the opioid prescription histories of patients using high doses in a North Wales GP practice. METHOD: All patients on high-dose opioids during the census week were identified. Summary graphs of the prescription histories were prepared. Qualitative analysis was conducted individually by four researchers. A workshop was held to arrive at a consensus about common features and to inform further quantitative analysis. RESULTS: A quarter of high-dose regimens were initiated outside the practice, either in a different primary care practice or in secondary care. The majority of the remaining patients showed a pattern of dose increases to high levels over a short period (median 3.5 months). None showed a pattern of gradual increases over a longer timescale. Most of the patients remained on high doses continuously once a daily dose of ≥120 mg oral morphine equivalent (OME) was reached. CONCLUSION: 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'.