Effects of Osteoarthritis Pain, Morphine, and Placebo on Neuroendocrine Function in Men

This study will examine the effects of morphine on leuteinizing hormone, testosterone, adrenocorticotropic hormone and cortisol in men. The use of long-term opioids, such as morphine, to treat patients with pain is increasing, despite a dearth of information about their effects on hormones. The study will also look at the effect of chronic pain on these hormone levels and the effect of placebo on pain.

Men between 30 and 65 years of age who have had moderate to severe chronic pain due to osteoarthritis for at least 3 months and healthy, pain-free men in the same age range may be eligible for this study. Patients taking an opioid-based medication such as percocet, vicodin, or morphine for pain relief, as well as patients who are not taking opioids, may participate. Candidates are screened with a medical history, physical examination, blood tests, including a blood test to look for possible "pain genes," electrocardiogram, x-ray, and questionnaires that assess the impact of pain on functional level and psychological well being.

This is a four-part study. Healthy volunteers and patients who are taking opioids for their arthritis pain end their participation after Part I; those who are not taking opioids continue with Parts II, III, and IV, as follows:

Part I: Participants are admitted to the NIH Clinical Center at 4 p.m. for an overnight stay. At 6 p.m. a catheter (plastic tube) is placed in a vein in the forearm and remains in place throughout the night. Blood samples of 3 cc's each (less than a teaspoon) are collected through the catheter every 20 minutes for 12 hours, from 8 p.m. until 8 a.m. Participants also collect their urine starting from 8 a.m. on the morning of hospital admission and continue the collection throughout their 24-hour hospital stay. Patients are discharged at the completion of the blood sampling.

Part II: Patients are randomly assigned to take morphine (MS Contin), placebo, or standard treatment, which consists of anti-inflammatory medications and acetaminophen as needed, but no opioids. (Patients in groups I and II are also permitted to take anti-inflammatory drugs and acetominophen, in addition to their study medication.) Patients are monitored for drug side effects by phone twice a week, and medication doses are adjusted as needed. The morphine dose is gradually increased over a 4-week period if no side effects develop. After 2 weeks on the highest dose of morphine, hormone blood levels are measured and patients complete questionnaires. Patients are readmitted to the hospital for a repeat blood sampling and blood collection as in Part I. Patients on morphine and placebo are then gradually tapered off drug over 12 days and remain drug-free for 2 days before starting Part III.

Part III: All patients are given morphine in this part of the study and are monitored for drug side effects by phone twice a week, with doses adjusted as needed. The morphine is gradually increased over a 6-week period if no side effects develop and is maintained at the highest dose for another 8 weeks. Hormone levels are measured and the blood and urine studies and questionnaires are repeated. Patients interested in continuing long-term treatment with MC Contin are referred back to their physicians with recommendations to that effect.

Part IV: Patients are followed by phone for 6 months, at which time they return to the Clinical Center for hormone level measurements, repeat blood and urine tests, and questionnaires.