An observational study assessing high dose opioid prescribing and associated adrenal insufficiency

Background Long-term opioid use is known to affect endocrine function, with case reports indicating an association with adrenal insufficiency. Aim This study aims to investigate long-term, high-dose opioid use (≥80mg morphine or equivalent per day) at a Suffolk (UK) General Practice and its effect on adrenal function. Method From a practice list of 18,300, retrospective data was collected for patients prescribed high-dose opioids for non-cancer pain for at least three months on current repeat prescription. Patient demographics and prescribing information were collected using SystmOne. Cortisol levels in the high-dose opioid patients, and short synacthen testing if indicated, were performed. Results The 35 identified patients (0.2% of practice list) were predominantly female (77%) ≥70 years old (37%), and taking opioids prescribed for osteoarthritis or back pain (77%). 6% were prescribed >280mg morphine or equivalent per day, with one patient prescribed 705 mg. Routine evaluation for development of adrenal suppression and subsequent management was poor. 31% (11 of 35) had developed symptoms potentially indicative of adrenal insufficiency. One of these patients was among the 21% (7 of 35) with suppressed serum cortisol. Adrenal insufficiency secondary to opioids was confirmed in one patient using short synacthen testing. There was no statistical difference in either opioid dose or months of use for those with or without early morning cortisol suppression. Conclusion The investigation highlights both the considerable use of high-dose opioids for non-malignant pain and their apparent association with adrenal suppression, demonstrating the need for formal guidelines to aid recognition and diagnosis.