by Richard Thompson, MD
EK Health Services' Chief Medical Officer
The U.S. Food and Drug Administration (FDA) is a part of the U.S. Department of Health and Human Services and is the federal watchdog Agency for food, drugs, medical devices, and vaccines. From time to time they issue recommendations that affect medications used for the treatment of chronic pain, a significant issue for workers’ compensation patients. Their recommendations are evidence-based and should be applied immediately as UR treatment guidelines, when applicable. Their recommendations invariably predate their inclusion in accepted national treatment guidelines because it often takes months to years to catch up.
In August 2009 the Agency announced its intent to take action against 8 companies that marketed OTC topical drug products containing Ibuprofen. These products, containing ibuprofen in combination with a variety of other active ingredients and marketed for pain relief, were unapproved. The Agency didn’t say they did not work, only that they were unapproved. Topical ibuprofen, like other topical NSAIDS, was marketed as a “safer” formulation than oral ibuprofen. However, such safety claims have never been reviewed by the FDA, nor has the Agency evaluated what side effects might be associated with such products. In theory, this FDA stance could apply to many other topical medications that have not produced any side effect profiles.
In December 2009 the Agency recommended that diclofenac products, the ingredient in Flector®, Voltaren Gel®, and Voltaren®, should not be used for prolonged treatment, due to potential liver toxicity and death. Cases of drug-induced hepatotoxicity have been reported within the first month of treatment with diclofenac, but can occur at any time during treatment. I consider this significant evidence for denying these products.
In November 2010 the Agency recommended that physicians stop prescribing and dispensing propoxyphene (the active ingredient in Darvon® and Darvocet®) to patients. They should contact patients currently taking propoxyphene-containing products and ask them to discontinue the drug, inform patients of the risks associated with propoxyphene, and discuss alternative pain management strategies. The recommendation was based on evidence that the drug can increase the risk for serious abnormal heart rhythms. It’s interesting that this would surface after more than 40 years of use!
In January 2011 the Agency recommended a significant change in the use of acetaminophen, the active ingredient in Tylenol®. They recommended physicians to advise patients not to exceed the acetaminophen maximum total daily dose (4 gram/day), and not to drink alcohol while taking acetaminophen-containing medications. The Agency also asked drug manufacturers to limit the strength of acetaminophen in prescription drug products, predominantly combinations of acetaminophen and opioids, to 325 mg per tablet or capsule, making these products safer. It is hoped this action will help reduce the risk of severe liver injury and allergic reaction (swelling of the face, mouth, and throat, difficulty breathing itching or rash) associated with acetaminophen. Examples of prescription medications containing acetaminophen commonly prescribed for chronic pain patients are Vicodin®, Lortab®, Tylox®, Percocet®. Used in both prescription and over-the-counter (OTC) products, acetaminophen is among the most commonly used drug in the US.
It could easily be argued the FDA warning about the dangers of acetaminophen in popular prescription pain drugs did not go far enough.
Acetaminophen is found in a wide range of over-the-counter and prescription drugs. At normal doses, when not taken with alcohol, acetaminophen is a very safe drug. But it's easy to take too much or unthinkingly combine it with alcohol -- a big mistake that can lead to serious liver damage.
Acetaminophen is the leading cause of acute liver failure in the U.S., causing some 1,600 failure cases a year. Liver damage can occur when a person with normal liver function takes 4,000 milligrams or more of acetaminophen in a single day, which is easy to do if a person is taking several medications (an all-too-common situation for chronic pain patients) and is not aware that each contains a powerful dose of acetaminophen. Acetaminophen overdoses also cause approximately 56,000 emergency-room visits, 26,000 hospitalizations, and 458 deaths a year.