September 27, 2011 (Las Vegas, Nevada) — Long-term use of opioids can take a substantial toll on the endocrine system, and patients receiving such therapies should be routinely screened and treated when hormone levels are abnormal, according to research presented here at the American Academy of Pain Management (AAPM) 22nd Annual Clinical Meeting.
Studies looking at the effects of opioids on the endocrine system typically only evaluate opioid use for a short time. In contrast, the study presented here profiled 18 patients, including 10 men and 8 women, with an age range of 40 to 75 years, who had been maintained on high-dose opioids (equivalent to 300 mg morphine for 20 or more years), explained lead author Forest Tennant, MD, a physician with the Veract Intractable Pain Clinic in West Covina, California.
"We came across these patients only because the physician at the rural clinic died and I was asked to come in and help out. We found they had just been maintained on opioids under the California Intractable Pain Act and had not been treated with hormones or any ancillary therapies," explained Dr. Tennant.
Fasting serum specimens taken for patients showed widely varied hormone abnormalities, and only 1 patient demonstrated normal levels on all 6 assays testing for cortisol, pregnenolone, testosterone, estrogen, corticotrophin, and follicle stimulation hormone (FSH).
The most common abnormalities were low FSH in 6 patients (33.3%) and low testosterone in 8 patients (44.4%).
In addition, high serum levels were found for corticotrophin (4 patients [22.2%]), estrogen (1 patient [5.6%]), cortisol (4 patients [22.2%]), and pregnenolone (1 patient [5.6%]).
Low pregnenolone and estrogen levels were observed in 1 patient (5.6%) each, and 2 patients (11.9%) had low cortisol levels.
"This study provides additional evidence that the major effect of opioids on the endocrine system is suppression of FSH and testosterone," the authors write. "Suppression may also affect other hormones, including cortisol, estrogen, and pregnenolone."
Although opioids have previously been shown to potentially suppress FSH and testosterone, Dr. Tennant said he was most surprised to see the other abnormalities.
"Severe intractable pain will overstimulate the pituitary gland and adrenal glands, and a person could suffer greatly and even die if the suppression is too great," he explained.
"We thought for people who had been on these drugs for 20 years, surely the opioids would have suppressed the pituitary to where it was not overactive. But we found in some cases that that was not true. The opioids were not controlling the pituitary and adrenal gland as well they should have been doing."
The findings underscore the need for clinicians to keep a close watch on hormone levels in patients with severe pain, Dr. Tennant emphasized.
"These are serious clinical findings and it should be a wake-up call for all of us. For physicians who are going to treat intractable pain, pituitary-adrenal-gonadal axis screening is critical, and patients should be clinically treated for deficient or excessive hormone levels."
Dr. Tennant has disclosed no relevant financial relationships.
American Academy of Pain Management (AAPM) 22nd Annual Clinical Meeting: Abstract 16. Presented September 21, 2011.
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Cite this: Endocrine Screening Recommended With Long-Term Opioid Use - Medscape - Sep 27, 2011.