Nancy A. Melville

October 04, 2012

October 4, 2012 (Phoenix, Arizona) — More than a third of pain patients prescribed opioids also test positive for prescribed psychotropic medications, such as antidepressants and anxiolytics, according to new research presented here at the American Academy of Pain Management (AAPM) 23rd Annual Clinical Meeting.

Patients with chronic pain often also have various other conditions, including depression and anxiety, leading to the use of selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, and other psychotropic medications.

To better understand the percentage of the population using polypharmacy, researchers at Millenium Laboratories in San Diego, California, evaluated urine drug testing results from more than 300,000 people who were using opioids and were tested for the presence of psychotropic medications.

The researchers found that 36% of all specimens (n = 95,881) showed at least 1 psychotropic medication that was reported as prescribed.

A breakdown of the prescribed medications included the following: fluoxetine, 86.5% (n = 225); paroxetine, 63.1% (n = 113); duloxetine, 62.4% (n = 748); venlafaxine, 76.1% (n = 245); amitriptyline, 63% (n = 3131); imipramine, 71.1% (n = 64); alprazolam, 68.5% (n = 24,568); clonazepam, 77.4% (n = 13,099); lorazepam, 68.4% (n = 4855); and oxazepam-based, 79.6% (n = 15,616).

The findings also showed that 13% to 37% of prescribed psychotropic medications were in fact not detected at the time of the urine drug testing.

"Since the symptoms of anxiety, depression and pain may influence each other, when a patient prescribed these medications reports to their clinician insufficient pain or symptom relief, testing for the medications before altering dosages or changing medications may help to make an informed decision as to which course of action is necessary," the authors write.

The authors noted that a limitation of the study was that the tests were performed only on the basis of physician request; therefore, the specimens were not tested for all possible compounds. In addition, few details were available regarding the nature of the prescription.

"It was not known if these medications were prescribed for pain, anxiety, or depression and some could have been prescribed to be taken as needed and not on a regular basis," they write.

Significant Mental Health Disorders

Prescription drug abuse expert Lynn R. Webster, MD, said the results appear to be in line with what's known about the relationship between chronic pain and associated mental health conditions.

"It's not surprising to me to see 36% because as many as 50% to 70% of patients with chronic pain have one or more mental health disorders," said Dr. Webster, who is medical director of Lifetree Clinical Research in Salt Lake City, Utah.

"Furthermore, many people who are on higher doses of opioids have more significant mental health disorders, so they very well could have different psychotropic drugs. Severe depression is very prevalent among chronic pain patients with a long history of chronic pain," he told Medscape Medical News.

As with any cases involving use of multiple drugs, a key concern is the potential for interactions, Dr. Webster added.

"Many of the psychotropic drugs can increase the opioid toxicity, and I believe that the addition or combination of psychotropic drugs and opioids is in fact one of the big reasons we have had an increase in unintentional overdose deaths."

The likely complexities in patients with chronic pain can make those patients as much a pharmaceutical challenge as those with any other complex conditions, Dr. Webster said.

I believe that the addition or combination of psychotropic drugs and opioids is in fact one of the big reasons we have had an increase in unintentional overdose deaths.

"It's not an easy challenge for clinicians due to the magnitude and diversity of disorders these patients may have," he explained.

"It's like a patient with renal failure, pulmonary failure and cardiac failure all at once — do you eliminate treatment of 2 of those disorders just to treat the third? It's the same with chronic pain, substance abuse, and mental illness — you can't treat any one without treating the others, which makes it polypharmacy and more risky."

Pain specialist Lawrence D. Robbins, MD, from the Robbins Headache Clinic in Northbrook, Illinois, added that the study is important in shedding light on the details of the challenging pharmaceutical situation that surrounds pain management.

"The major point of this excellent, large study is that in patients with pain, anxiety and depression, and subsequently the medications for these, coexist as common comorbid conditions," he told Medscape Medical News.

"[That is] well known and not a surprise, but it is just that we are treating these comorbid conditions in the same population, so they often end up on pain as well as psychiatric medications."

The study's authors are employees of Millennium Laboratories. Dr. Webster reports that he receives consulting fees from Boston Scientific Corporation, Covidien, Iroko Pharmaceuticals, Medtronic, Nektar Therapeutics, Pfizer Inc, and Salix Pharmaceuticals. Dr. Robbins has disclosed no relevant financial relationships.

American Academy of Pain Management (AAPM) 23rd Annual Clinical Meeting. Poster Abstract #21. Presented September 21, 2012.