The Changing Landscape of OTC Acetaminophen Pain Products

Pain Management, November 2011, Volume 4, Issue 8

Recent labeling and dosage revisions to pediatric OTC products may be a sign of future changes for adult products.

The FDA has acted recently to make consumers more aware of the risks associated with the use and overuse of acetaminophen-containing products, including boxed warnings about potential safety risks, and recommendations from advisory committees to include weight-based dosing on the labels of pediatric products and restricting solid oral dosages to a single concentration. Advisory committees have previously recommended similar changes for adult products.

In May, 2011, the FDA’s Nonprescription Drugs Advisory Committee and Pediatric Advisory Committee met to consider whether weight-based dosing directions should be added to the existing age-based labeled dosing directions for children ages 2-12; whether the existing data supported the addition of new labeled dosing directions (10-15 mg/kg) for children age 6 months-2 years; and whether pediatric single-ingredient, acetaminophen-containing solid oral dosage forms should be restricted to a single dosage/concentration. Based on the testimony and data presented at the meeting, the panel voted unanimously in favor of adding weight-based dosing to the labels of these products, with a “a fairly strong consensus” that “the weight should be listed first and that the label should reflect in some way the priority towards weight-based dosing” (http://1.usa.gov/sNGA1A). On the question of whether the pharmacokinetic, safety, and efficacy data support the addition of new labeled dosing directions corresponding to a 10-15 mg/kg dose for children age 6 months-2 years, the panel again voted “yes” unanimously. The panel also recommended that “infant acetaminophen should be labeled only for fever reduction in children age 2 and under, but labels may recommend acetaminophen for both fever and pain in children age 2 and older” (http://bit.ly/u6SOIB). On the final question, of whether the FDA should consider restricting all oral dosage forms of pediatric acetaminophen-containing products to a single concentration, the panel voted 17 in favor and three against, with one abstention. Although the FDA usually follows the advice and recommendations of the advisory committees, it is not required to do so.

Questions for our readers:

Do you recommend OTC acetaminophen products to your patients for mild to moderate pain?

In your experience, are patients generally well-informed about the risks associated with these medications?

Are they aware of the recommended daily maximum dose for acetaminophen, and of the fact that many products may also contain acetaminophen in addition to other active ingredients?

Do you agree with the recommendations of FDA advisory committee to include weight-based dosing on the labels of pediatric acetaminophen-containing products? Do also agree with the move to limit these products to a single concentration?

Did you support the FDA advisory committee recommendations in 2009 to lower the maximum total daily dose of nonprescription acetaminophen from 4,000 mg/day?

Should the maximum nonprescription single adult dose be limited to 650 mg (or do you favor a different maximum single dose strength)?

E-mail answers and comments to tkunkler@mdmag.com.

In a related move, two weeks prior to the FDA advisory committee meeting, the Consumer Healthcare Products Association (a trade association for OTC medication manufacturers) announced that the makers of OTC single-ingredient liquid pediatric acetaminophen medicines were voluntarily taking steps “to convert these pediatric products to just one concentration” (http://bit.ly/ilgITq). After the changeover (which began in mid-2011), “the current children’s strength of liquid acetaminophen (160 mg / 5 mL) will become the only liquid concentration available for all children under 12-years-old, and the current concentrated infant drops will no longer be sold.”

The FDA and prescription acetaminophen dosing: Part of the bigger picture

Earlier this year, in response to reports of severe liver injury associated with the use of acetaminophen-containing products, the FDA asked manufacturers of oral prescription acetaminophen combination products to “limit the maximum amount of acetaminophen in these products to 325 mg per tablet, capsule, or other dosage unit, with the exception of intravenous injection” (http://1.usa.gov/geRlmv). The FDA took this action in part because patients often do not know that the product they are using contains acetaminophen (there are over 600 products available), and they do not know what the recommended daily dosage is, or the risks and dangers associated with exceeding the dosage recommendations. The FDA said it believes this action “will reduce the risk of severe liver injury from acetaminophen overdosing, an adverse event that can lead to liver failure, liver transplant, and death. The FDA also directed manufacturers of these products to add a boxed warning to the label of all prescription drug products that contain acetaminophen describing the risks of severe liver injury. Companies will have until January, 2014 to comply with the new requirements. However, these new dose limits will apply only to prescription products that contain acetaminophen; for now, OTC products are not affected by the new 325 mg limits. But, if the FDA’s recent statements and past actions are any indication, this may not be the case for long.

Additional Questions and Comments from the 2009 Joint Meeting of the FDA Drug Safety and Risk Management Advisory Committee, Nonprescription Drugs Advisory Committee, and the Anesthetic and Life Support Drugs Advisory Committee

Committee member comments from the discussion around lowering the recommended daily maximum dose from 4,000 mg/day and limiting the maximum nonprescription single adult dose to 650 mg:

“Although the toxicity data for the 4 gram/day dose was not compelling it is clear that there is a small window between the dose that is therapeutic and the dose that may be toxic.”

“The potential for unintentional overdosing is most likely to occur when the patient is standing in front of a shelf making a decision on their own.”

Comments from the discussion around whether the committee recommends switching “the current maximum dosage of acetaminophen (i.e., 2 x 500 mg)” to prescription status:

“I feel comfortable with patients being able to obtain 500mg tablets without an office visit.”

“Making 500mg tablets prescription only would be a barrier to care, particularly for the elderly.”

“Making the 500mg tablets prescription is a compromise, making the formulation available and giving the practitioner an opportunity to discuss the toxicity with the patient.”

The advisory committee in 2009 was also asked to consider recommending whether pack size limits should be implemented for nonprescription acetaminophen products (the UK had recently put into place mandated pack size restrictions with no mandated sales restriction).

“If pack size of acetaminophen is restricted, consideration should be given to limiting pack size of nonsteroidals (ibuprofen and naproxen) and salicylates (aspirin) to avoid an inadvertent, unintentional, impact on safety.”

“Consider the negative impact that limiting the pack size may have on: the elderly who are not mobile, people who have to take acetaminophen for chronic pain, people who live in rural areas and large families.”

“Skepticism that decreasing the pack size will have any impact on preventing liver toxicity, given that there is conflicting data from the UK experience, even with their large educational campaign.”

More moves to come in the future?

The FDA recently announced that it is “currently working to address the recommendations of the Advisory Committee with regard to OTC acetaminophen products. Additional safety measures relating to OTC monograph products will be taken through separate action, such as a rulemaking as part of the ongoing OTC monograph proceeding for internal analgesic drug products” (http://1.usa.gov/geRlmv). This would appear to be a continuation of previous attempts to address safety issues related to OTC acetaminophen products. In 2009, an FDA advisory panel voted by a fairly narrow margin to recommend the agency to reduce the maximum daily dose of nonprescription single ingredient and combination acetaminophen-containing products from 4 grams per day, but did not recommend a new maximum dose (see sidebar). The panel also voted to limit the maximum nonprescription single adult dose of acetaminophen to 650 milligrams, and voted to make the 1,000 mg dose of acetaminophen available only by prescription (http://1.usa.gov/vE92YQ). Some manufacturers are not waiting for the FDA to mandate additional labeling and dosage changes; in July the maker of Extra Strength Tylenol announced that it was voluntarily lowering the maximum daily dose from 4,000 mg/day to 3,000 mg/day, “to help encourage appropriate acetaminophen use and reduce the risk of accidental overdose” (http://bit.ly/qP7734).

With some makers of OTC acetaminophen-containing products taking voluntary steps in some cases to reduce the maximum dose of their products, more public attention being drawn to the potential renal effects associated with prolonged high levels of acetaminophen use, and calls for greater attention to be paid to consumers’ lack of information and education regarding key features of OTC acetaminophen products (dosage strength, whether the product contains acetaminophen, maximum daily dose, appropriateness for use in infants and children, etc), it is hardly surprising that the FDA and industry may take additional steps in the future to clarify the labeling on these products and streamline the choices available to consumers.