Most patients taking opioids for low back pain or other pain syndromes are prescribed low-to moderate doses, but a substantial number are given higher doses. Although there is no consensus on an absolute limit because tolerance varies over time among individual patients, what is known, however, is higher does are associated with elevated risks for side effects, addiction, overdoses and death. A study published by Oregon Health and Sciences University in The Journal of Pain showed that patients on higher doses of opioids had higher rates of psychiatric problems, co-prescriptions of sedatives and health care services utilization.

The Journal of Pain is the per-review publication of the American Pain Society.

For the study, the research team sought to examine correlates of higher dose opioid use among patients in primary care settings being treated for low back pain. The goals were to determine the prevalence of higher dose opioid prescribing, identify the demographic and clinical characteristics of patients receiving higher doses, and examine health services utilization patterns among high-dose users.

Electronic pharmacy and medical records were examined for 26,000 adults 18 and older diagnosed with low back pain, of which 61 percent received an opioid prescription. Among patients receiving long-term opioid treatment, nearly 9 percent received a higher dose in their final prescription. Patients receiving higher doses of opioid therapy were prescribed a median daily dose of 180 mg per day, which was seven times greater that patients receiving lower doses.

The analysis showed that chronic pain patients with comorbid psychiatric diagnoses are more likely to be prescribed opioids compared with patients without psychiatric problems. The authors found that the prevalence of mental health diagnoses increases with longer duration of opioid use. Studies have indicated a relationship between depression and persistent pain and that each could have a causative influence on the other. Thus, depression may lead to more opioid use and opioid use may cause or exacerbate depression.

The authors concluded their results should prompt physicians to screen opioid therapy candidates for mental health and substance use disorders.

Another finding reported in the study showed that patients in the higher dose group were frequent consumers of medical services, including visits to emergency departments. Also, higher dose patients had the largest number of different prescribers, which could indicate continued uncontrolled pain, continuity of care problems or "doctor shopping."