Managing Comorbid Conditions Associated with Chronic Pain

Pain has been associated with a number of conditions, including addiction, depression, and anxiety. Pain, as a separate condition, is very difficult to treat, but layer in the effects of depression, anxiety, and/or addiction; it can be even more complicated to treat. A key to treating pain is also treating depression, anxiety, and addiction. A strong understanding of the medications available and how to most effectively utilize them in clinical practice is essential.

During a morning session at the 2013 American Academy of Pain Medicine annual meeting, held April 12-14 in Fort Lauderdale, FL, Binit J. Shah, MD, and Christina M. Delos Reyes, MD, of Case Western University School of Medicine in Cleveland, OH , provided an overview of psychopharmacology and pharmacology for addiction and other conditions.

During the session, Shah discussed the epidemiology of depression and provided an overview of the medications available to treat depression. While some antidepressants are only effective for pain and anxiety, some are also effective in managing comorbid pain. The good thing with antidepressants is that they work, said Shah. Recent studies have demonstrated that 50-70% of patients that take an antidepressant experience symptom improvement. While suicidal thoughts and ideation are a risk with some of the antidepressants, the risk is minimal and limited mainly to patients under 25 years of age.

Shah walked through the types of antidepressants, including tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin—norepinephrine reuptake inhibitors (SNRIs), and other agents. He provided insight into the different types of drugs in each of these categories and provided information on associated side effects, effective dosing for depression and pain, as well as management and expectations of treatment.

Duloxetine has the most indications for pain and has dosing for both mood/anxiety as well as for pain. Milnacipran is approved in the United States for the treatment of fibromyalgia but may also have anti-depressive effects because it is approved in the European Union for depression. SSRIs have been disappointing in the management of pain relief but very effective for treating mood and anxiety. Benzodiazepines are typically overprescribed and less effective in practice than had originally been thought. Most society guidelines do not recommend benzodiazepines for anxiety, post traumatic stress disorder, panic disorder, and general anxiety disorder.

Other agents are available for treating pain and associated comorbidities, and understanding where to start is important. Typically, for patients who present with pain and depression, duloxetine is a good first line approach, followed by escitalopram or sertraline (SSRIs). If neither of those approaches work then switching to another SSRI may provide better outcomes. If that still doesn’t provide any relief of pain or mood symptoms then using a combination or augmented therapy approach may be another option. However, patients being put on a combination or augmented therapy approach should be referred to specialist who can monitor them more closely.

Reyes further expanded upon pharmacology for addiction and provided an overview of the epidemiology of addiction. Approximately 15.9% of individuals in the United States will experience drug abuse at some point in their lives and approximately 31% will experience risky use of drugs, including binge drinking and drunk driving. There is a large treatment gap in addiction, with only one in 10 people with addiction getting the treatment that is needed.

There are a number of agents available for the treatment of alcohol dependence, opioid dependence, and nicotine dependence. Agents available for alcohol dependence include disulfiram, which breaks down alcohol and is an action stage treatment; acamprosate, which reduces withdrawal after refraining from drinking; and naltrexone, which is available as an oral medication and injection and used for both opioid addiction and alcohol dependence. Other agents that can be used for alcohol dependence include topiramate, which would be considered off label, nalmetone, and ondansetron, which is commonly used in younger alcoholics and decreases the number of days of drinking per month.

Agents available for opioid dependence include naltrexone, methadone, and buprenorphine, which can be difficult to prescribe due to regulations on the number of patients a physician can treat with the medication. Other agents used for nicotine addiction including nicotine replacement therapy with the patch, bupropion, nortriptyline, rimonabant, nicotine vaccine (not FDA approved), and varenicline.