Acetaminophen toxicity is the second most common cause of liver failure requiring transplantation in the US.
On January 14, 2014, the FDA recommended that health care professionals discontinue prescribing and dispensing prescription combination drug products containing more than 325 mg of acetaminophen per tablet, capsule, or other dosage unit. The FDA’s advisory notice also stated that there were no available data to show that taking more than 325 mg of acetaminophen per dosage unit provided additional benefit outweighing the added risks for liver injury.
This is no surprise. The FDA has been concerned about acetaminophen use for many years. In the January 14 safety alert, the FDA noted that there have been cases of severe liver injury with acetaminophen in patients who took more than the prescribed dose of an acetaminophen-containing product, took more than one acetaminophen-containing product at the same time, or consumed alcohol while taking acetaminophen products.
In January 2011, the FDA asked manufacturers of prescription combination drug products containing acetaminophen to limit the amount of the drug to no more than 325 mg in each tablet or capsule by January 14, 2014. More than half of manufacturers voluntarily complied with the FDA’s request; however, prescription combination drug products containing more than 325 mg of acetaminophen per dosage unit remain available. The FDA now intends to institute proceedings to withdraw approval for these products.
In the interim, FDA recommends that healthcare providers consider prescribing combination drug products containing 325 mg or less of acetaminophen, and that pharmacists contact prescribers to discuss using products with lower doses of acetaminophen when they receive prescriptions for products containing more than 325 mg per unit dose. Implicit in the FDA’s statement is that prescribers must make individual dosing determinations and consider the amounts of both the acetaminophen and opioid components when prescribing combination drug products.
I have previously commented on the FDA’s decision to make hydrocodone a schedule II product. In light of this new advisory to monitor acetaminophen dosages, I think it probably is time to stop writing for combination products, and just prescribe the opioid desired as a single entity, then recommend a separate amount of acetaminophen, ibuprofen, naproxen, or whatever other agent. It will be permissible to order two unit doses to be taken at once, allowing up to 650 mg of acetaminophen along with an opioid (codeine, hydrocodone or oxycodone), but single-entity prescribing will be safer since the only acetaminophen taken will be known to patients. There are just too many “invisible” sources of acetaminophen, making it hard for patients to always know how many mg they are taking daily.
Depending upon your point of view, the age of your patient, and his or her use of alcohol, you may want to consider lowering the amount of acetaminophen to less than 2000 mg daily for healthy non-alcohol users, and less than 1000 mg daily for those who regularly consume alcohol.
In the United States, acetaminophen toxicity has replaced viral hepatitis as the most common cause of acute hepatic failure and is the second most common cause of liver failure requiring transplantation. This is an easily correctable problem.
B. Eliot Cole, MD, MPA, is a member of the Pain Management editorial advisory board. He has served in executive positions for several prominent pain management organizations and societies, including the American Society of Pain Educators and the American Academy of Pain Management. He has been a pain management fellow, clinician, educator, and advocate for nearly 30 years and has practiced in a variety of settings serving a wide range of patients.