Thursday, August 20, 2009

10+ Years on Opioid Analgesics! What Happens?

Little is known about outcomes in patients receiving very long-term opioid therapy for chronic noncancer pain conditions. In a first-of-its-kind study, Forest Tennant, MD, reports on a group of patients administered strong opioids for from 10 to 35 years. All indications are that significant pain relief and ongoing quality of life and physical functioning enhancements outweigh complications of the therapy, which are easily managed.

Tennant’s study included 24 patients aged 30 to 79 years, two-thirds females, and primarily suffering from post trauma neuropathies and arthropathies (29%), spinal degeneration (25%), abdominal adhesions or neuropathies (20%), or fibromyalgia (12.5%). They had been receiving continuous opioid therapy for from 10 to 35 years, taking a long-acting formulation of either morphine, oxycodone, or fentanyl, or methadone. One or more short-acting opioids also were prescribed for pain flares or breakthrough pain. Patients also were prescribed muscle relaxants, sleep aids, hormone replacement medications, and/or dietary supplements as appropriate.

Nearly all patients (92%) reported that their pain was permanently decreased, and the great majority (83%) believed that the opioid regimen continued to relieve their pain as well as it did when treatment first began. All patients reported they could perform a variety of activities and physical functions that they could not do prior to opioid therapy. Hormonal abnormalities were a significant complication in males, which were managed with hormone replacement therapy. Some patients developed other conditions during long-term opioid therapy, including tachycardia, hypertension, hyperlipidemia, diabetes, tooth decay, and weight gain. All of these could be medically managed and whether they were pain related, opioid produced, or simply inherent in the patients and/or a result of aging is unclear at this time. No neurologic complications such as hyperalgesia, dementia, tremor, or seizures were noted; nor were hepatic, renal, or gastrointestinal complications, except for minor constipation.

Tennant concludes: “Even though the number of patients evaluated here is relatively small, the great improvement in their quality of life and physical functioning is so positive and the complications of the therapy so easily managed that long-term opioid therapy should continue to be provided and evaluated.”

Commentary: Overall, the reported outcomes in this study offer hope for patients who might benefit from long-term opioid therapy for chronic or intractable noncancer pain conditions, and Tennant is to be commended for his independent research, which was not supported by outside funding. His study helps to confirm the legitimization of pain as a chronic illness in certain patients and opioids as a justifiable long-term therapy. So much of the literature these days speaks rather negatively of prolonged opioid-analgesic therapy and portrays patients who thrive on those medications as potential drug seekers or abusers needing intense surveillance. Such a perspective would be unheard of if considering insulin or antihypertensives for chronic diseases like diabetes or hypertension, respectively.

It is noteworthy in Tennant’s study that opioid tolerance, hyperalgesia, and constipation were not observed as therapy-limiting complications. The significance of certain other medical complications needs better assessment, taking into account that these were quite ill patients at the outset and the possibility of natural aging or disease-progression effects during many years of treatment. As Tennant acknowledges, his investigation depicts a relatively small case series, and much additional study is needed to determine any cause-effect relationships of medical complications in opioid-maintained patients. This sort of longitudinal study should be replicated in a much larger group of patients, and Tennant is searching for additional practitioners with patients who have been opioid-treated for 10 to 20 years. Ideally, however, these patients might at the least be compared with a matched cohort of patients with chronic pain conditions receiving other than opioid-centered pain-management regimens.

ADDENDUM: See the latest update on this research (now including 100 cases) at the blogpost “Followup: Safety of Long-Term Opioid Therapy.”

Reference: Tennant F. A 10-year evaluation of chronic pain patients treated with opioids. Heroin Addict Relat Clin Probl [Europad Journal]. 2009;11(1):31-34. [Article PDF available, see p. 31]