Androgen Deficiency in Long-Term Intrathecal Opioid Administration

Background: Intrathecal drug delivery of opioids is an efficient and effective treatment option for pain management in the chronic nonmalignant pain population. As with all treatments, in addition to the benefits, risks and side effects exist. One such risk in intrathecal opioids is opioid-induced androgen deficiency. Objective: This study evaluates opioid-induced androgen deficiency in long-term intrathecal opioid administration in chronic nonmalignant pain. Study Design: Case series. Sixteen consecutive patients with intrathecal drug delivery with opioids were screened for androgen deficiency. Setting: Academic university-based pain management center. Method: All the subjects were seen in a 2 month period, during a scheduled maintenance refill visit. Eight consecutive men and eight consecutive women receiving intrathecal drug delivery therapy for non-malignant chronic pain were ordered blood work and asked to complete a questionnaire. Patient and patient-related data were also collected. Results: Ten of the 16 (62.5%) patients were found to have androgen deficiency, 4 of 8 men based on free testosterone levels and 6 of 8 women based on DHEA levels. In men, erectile dysfunction correlated with endocrine dysfunction (P = 0.02) while depressive symptoms correlated in women (P = .03). Overall, 2 of the 16 patients had hydromorphone as the opioid in the intrathecal system. Both patients had normal endocrine functions. Both patients with hydromorphone were men and the use of hydromorphone showed an insignificant trend (P = 0.06). Three of the 4 men with normal endocrine functions had in addition to an opioid, bupivacaine, in the intrathecal system. The presence of bupivicaine in men was significant (P = 0.02). No women had bupivicaine while one of the 8 women had clonidine in addition to the opioid. Presence of another substance in addition to the opioid showed an insignificant trend (P = 0.08). Limitations: Study limitations include the small sample size and case series nature. Additionally the symptoms data was solely based on subjective patient reports. Conclusions: Androgen deficiency is common in patients treated with intrathecal opioids for chronic nonmalignant pain. Patients experience numerous and wide ranging symptoms. Erectile dysfunction may be more suggestive for androgen deficiency in men while complaints of depressed mood may be correlative in women. Additionally, combining bupivicaine with the intrathecal opioid may provide a protective role. Key words: Androgen deficiency, endocrine dysfunction, chronic nonmalignant pain, intrathecal opioid, intrathecal drug delivery, side effects