Saturday, January 12, 2013

What Do Specialists Prescribe for Pain?

PrescriptionPain is often managed pharmacologically, but prescribing practices may vary and not always follow established guidelines. An enlightening recent survey of pain medicine specialists in the United States examined their practices and opinions regarding the efficacy, doses, and procedures to monitor the use and safety of commonly prescribed analgesic agents.

For this study, Honorio T. Benzon, MD and colleagues at Northwestern University Feinberg School of Medicine in Chicago mailed surveys to members of 3 U.S. pain-specialty organizations to solicit current expert opinions [Benzon et al.2012]. Three mailings were sent from January 2010 to January 2011 to 2,938 physician members of the American Academy of Pain Medicine (AAPM), the American Pain Society (APS), and the American Society of Regional Anesthesia and Pain Medicine (ASRA).

The survey questionnaire contained 49 questions on topics relating to pharmacotherapy for pain and preferences for using medications in different pain syndromes. A total of 474 physicians responded (16% return), more than two-thirds (69%) were specialists in anesthesiology or physical medicine and rehabilitation, and the majority had more than 6 years’ experience. Here are some highlights of their responses:

  • 72% ask patients to sign a treatment agreement when prescribing opioids; however, only 35% ask patients with alcohol or drug abuse to sign one, while 45% may not use an opioid agreement/contract initially but do so if treatment becomes long-term. A majority, 70%, require a treatment agreement if patients demonstrate aberrant drug-using behaviors (eg, lost prescriptions, frequently running out of medication).

  • More than half, 59%, order random urine drug testing in patients prescribed opioid analgesics.

  • 69% allow patients to drive once their opioid dose becomes stable and 85% do not think there is a maximum dose of opioids with respect to driving; although, there is no current agreement on this issue, according to Benzon et al.

  • When prescribing methadone for pain, 43% order baseline ECGs on all patients, while 34% only order the test if there are suspected cardiac problems or in elderly patients. When the methadone dose reaches 50 to 100 mg/day, 36% of respondents convert to another drug, while 43% do not convert at any dose unless there is a clinically evident problem.

  • About half of respondents (51%) prescribe codeine-containing agents, and most (up to 60%) prescribe this drug for Caucasians and Asians, and 11% for children <12 years of age — all of whom may have difficulty properly metabolizing the drug, as noted by Benzon and colleagues.

  • For treating drug-related constipation a combination of laxative and stool softener was most often preferred (46%), followed by a stool softener (eg, docusate sodium, 20%). Least preferred, by 52% of respondents, was subcutaneous methylnaltrexone, a peripheral opioid receptor antagonist. Bulking agents were favored by 16% and least preferred by 11%, although most guidance recommends against the use of such agents due to risk of bowel obstruction in these cases, Benzon et al. note.

  • Ondansetron was most preferred, by 51%, for treating opioid-related nausea, while antihistamines (diphenhydramine, meclizine) were least preferred (35%) for this adverse effect.

  • While 42% of respondents stated that the maximum daily dose of acetaminophen is 3,000 mg, almost all (91%) would caution patients against moderate/heavy alcohol consumption while taking the drug and 75% would decrease the dose in patients who are known moderate to heavy drinkers.

  • For older persons, two-thirds (66%) of the specialists order acetaminophen as an initial choice of analgesic, followed by COX-2 inhibitors and then NSAIDs (16%, often along with a proton pump inhibitor).

  • Overall, opioids were most preferred as first-line therapy for cancer pain, while anticonvulsants were preferred for herpetic neuralgia, diabetic peripheral neuropathy, complex regional pain syndrome, radiculitis, spinal cord injury, postamputation pain, and chronic postsurgical pain. Pregabalin was noted as most preferred for fibromyalgia.

  • Secondarily for the above conditions, respondents noted other drugs or combinations as important, including opioids for noncancer pain, topical lidocaine, duloxetine, milnacipran, and tricyclic antidepressants.

  • Of the antidepressants, nortriptyline was most preferred (54%), followed by amitriptyline (42%). Roughly half (54%) of respondents do not order an ECG at all when prescribing tricyclic antidepressants, despite increased risks of adverse cardiovascular effects with these drugs, as noted by Benzon and colleagues.

  • The survey found that 62% of respondents would decrease the dose of tramadol in patients taking SSRI, SNRI, and MAOI antidepressants to avoid possible serotonin toxicity; however, more than a third of respondents might not have been aware of this serious interaction, Benzon et al. suggest.

  • The most preferred musculoskeletal relaxants were tizanidine or cyclobenzaprine (each named by 26% of respondents), followed by baclofen (19%) and metaxalone (16%). Only 4% chose carisoprodol as being most preferred, while 41% chose this as least preferred.

The information above reflects practices and opinions of survey respondents and are not suggested as recommended or approved medical practices. Benzon and colleagues conclude from their survey that the responses pertaining to opioid agreements, urine drug testing, acetaminophen dosing, and treatments for neuropathic pain are reassuring in that they help to prevent misuse and abuse of opioids, control acetaminophen-induced hepatotoxicity, and reflect evidence-based treatments. However, they express concerns about identified gaps in knowledge, including the prescription of codeine in certain populations and the disuse of ECGs in patients on antidepressants. They stress that further education of physicians who treat chronic pain pharmacologically is warranted.

COMMENTARY: This was an important survey and the journal article contains much more detailed information than space above allowed; so, readers may want to acquire the full text [see link in reference below, subscription or purchase required]. A major strength of this survey was that, while other researchers have examined attitudes and practices relating to opioids, this current investigation was an open-ended consideration of all drugs commonly used in pain management.

However, the exploration was limited primarily to cancer, neuropathic, and fibromyalgia pain syndromes. This is unfortunate, but a more extensive survey covering additional pain conditions might have made the questionnaire forboding to recipients. As it is, another limitation of the study was that the response rate was relatively low (16%) among the total sampling of pain specialists mailed surveys.

There is no way of knowing if survey results reflect the knowledge and practices of the best-of-the-best practitioners in the pain field, or from a broader cross-section of specialists who merely had extra time available to answer questions. Some knowledgeable readers may disagree with the opinions and practices of survey respondents.

More studies of this nature seem essential, particularly because of the knowledge gaps and certain debatable practices identified. And, one might suspect — as Benzon et al. allude to at the end of their article — that the pain management knowledge and practices among nonspecialist healthcare providers might be even more deficient.

PT IconNOTE: Various documents at discuss pharmacotherapy for different pain conditions, with many addressing educational gaps identified by the above survey. Go to for documents focusing on opioid therapy, and for papers on select pain disorders. Look for the “PT” icon, which denotes papers we have created especially to fill important knowledge gaps.

REFERENCE: Benzon HT, Kendall MC, Katz JA, et al. Prescription Patterns of Pain Medicine Physicians. Pain Practice. 2012; online ahead of print [abstract here].

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