News Release

New Health Economic Data on Mallinckrodt's OFIRMEV® (Acetaminophen) Injection Published in Journal of Knee Surgery

-- Retrospective Analyses Provide Insights On Use of IV Acetaminophen Compared to Oral Acetaminophen in Total Knee Arthroplasty --
-- IV Acetaminophen Use Associated with Shorter Hospital Stays, Fewer Admissions to Skilled-Nursing Facility and Fewer Readmissions --

STAINES-UPON-THAMES, United Kingdom, July 9, 2018 /PRNewswire/ -- Mallinckrodt plc (NYSE: MNK), a leading global specialty pharmaceutical company, today announced two retrospective analyses that provide health economic insights on use of OFIRMEV® (acetaminophen) injection – intravenous (IV) acetaminophen – in total knee arthroplasty (TKA) and its impact on length of stay, discharge status and readmissions. Results from these two studies were recently published in the Journal of Knee Surgery.

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The intended audiences of these studies are population-based decision makers with knowledge and expertise in the area of health care economic analysis and its limitations.

"Postoperative pain can be difficult to control after TKA," said Tunde Otulana, MD, Chief Medical Officer at Mallinckrodt. "We are pleased to share these additional studies that provide health economic insights concerning IV acetaminophen in the management of acute pain in the surgical setting."

Both retrospective analyses were conducted in the Premier Inc. inpatient hospital database of patients who underwent TKA, and who received either IV or oral acetaminophen from the day of surgery up to day 3 as part of their postoperative pain management, from January 2012 to September 2015. A total of 134,216 patients receiving oral acetaminophen and 56,475 patients receiving IV acetaminophen were included in the two studies.

Impact of Intravenous Acetaminophen on Lengths of Stay and Discharge Status after Total Knee Arthroplasty1 assessed the postoperative outcomes of TKA patients who received IV acetaminophen versus oral acetaminophen, evaluating the hospital lengths of stay and discharge dispositions. Lengths of stay were calculated as the number of days from the date of hospital admission to the date of discharge, and the discharge disposition was categorized as to home or to a skilled nursing facility (SNF).

Key highlights of the analyses, after adjusting for baseline characteristics between treatment groups, include:

  • Compared with the oral group, the IV acetaminophen group had a 0.14-day shorter length of stay (95% confidence interval2 [CI], –0.15 to –0.13; p < 0.001).
  • Compared with the oral group, the IV group was 22% more likely to be discharged to home (odds ratio [OR] = 1.22; 95% CI, 1.19 to 1.25; p < 0.001).
  • Compared with the oral group, the IV group was 13% less likely to be discharged to a SNF (OR=0.87; 95% CI, 0.85 to 0.90; p < 0.001).

Intravenous Acetaminophen May Be Associated with Reduced Odds of 30-Day Readmission after Total Knee Arthroplasty3 evaluated 30-day hospital readmission rates in TKA patients who received either IV or oral acetaminophen perioperatively and sought to extrapolate the potential annual cost savings on a national level. All causes of readmissions that occurred between patient discharge and 30 days post discharge were recorded.

Key highlights include:

  • The readmission rate was 0.04% in the IV and 0.14% in the oral acetaminophen cohorts.
  • After adjusting for baseline characteristics between the treatment groups, IV acetaminophen was associated with a 71% decreased likelihood of readmission within 30 days (OR=0.29; 95% CI, 0.23 to 0.351; p < 0.001) when compared to oral acetaminophen.
  • The reduction in readmissions in the IV acetaminophen group may potentially result in $160 million savings per year on a national level, after accounting for the medication cost.

These two analyses were company-sponsored and conducted in collaboration with researchers primarily from the University of Washington School of Pharmacy, Cleveland Clinic and Joint Replacement Center of Texas.

Limitations of these Studies

  • Data from these studies were obtained from a large observational administrative database, which can be subject to errors in data collection or data entry.
  • Dosage and amount of acetaminophen were recorded from hospital charges instead of what was actually given to the patients.
  • Other adjuvant pain control modalities, such as nerve blocks and wound infiltration, were not assessed or controlled for. However, potential for bias is minimized since these modalities are commonly used with both IV and oral acetaminophen.
  • Like other healthcare databases, the Premier database can only capture patient records after readmission to the same network hospital. Therefore, the true readmission rate might actually be larger.

OFIRMEV (acetaminophen) injection is indicated for the management of mild to moderate pain in adult and pediatric patients 2 years and older, the management of moderate to severe pain with adjunctive opioid analgesics in adult and pediatric patients 2 years and older, and the reduction of fever in adult and pediatric patients.


See full prescribing information for complete boxed warning

Take care when prescribing, preparing, and administering OFIRMEV Injection to avoid dosing errors which could result in accidental overdose and death. In particular, be careful to ensure that:

• the dose in milligrams (mg) and milliliters (mL) is not confused;

• the dosing is based on weight for patients under 50 kg;

• infusion pumps are properly programmed; and

• the total daily dose of acetaminophen from all sources does not exceed maximum daily limits.

OFIRMEV contains acetaminophen. Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed the recommended maximum daily limits, and often involve more than one acetaminophen-containing product.

Acetaminophen is contraindicated:

  • In patients with known hypersensitivity to acetaminophen or to any of the excipients in the IV formulation.
  • In patients with severe hepatic impairment or severe active liver disease.


  • Administration of acetaminophen in doses higher than recommended (by all routes of administration and from all acetaminophen-containing products including combination products) may result in hepatic injury, including the risk of liver failure and death.
  • Use caution when administering acetaminophen in patients with the following conditions: hepatic impairment or active hepatic disease, in cases of alcoholism, chronic malnutrition, severe hypovolemia, or severe renal impairment (creatinine clearance ≤ 30 mL/min).
  • Discontinue OFIRMEV immediately at the first appearance of skin rash and if symptoms associated with allergy or hypersensitivity occur. Do not use in patients with acetaminophen allergy.
  • Take care when prescribing, preparing, and administering OFIRMEV injection to avoid dosing errors which could result in accidental overdose and death. (5.3)


  • The most common adverse reactions in patients treated with OFIRMEV were nausea, vomiting, headache, and insomnia in adult patients; nausea, vomiting, constipation, and pruritus in pediatric patients.

For additional Important Safety Information, including complete Boxed Warning, please click here for Full Prescribing Information, which can also be found at

ABOUT OFIRMEV (Acetaminophen) Injection
OFIRMEV is the first and only IV formulation of acetaminophen to be approved and currently marketed in the United States. The U.S. Food and Drug Administration approved OFIRMEV in November 2010. OFIRMEV is available to hospitals and outpatient and ambulatory surgical centers across the U.S.

This release includes forward-looking statements concerning OFIRMEV® (acetaminophen) injection, including anticipated benefits associated with its use. The statements are based on assumptions about many important factors, including the following, which could cause actual results to differ materially from those in the forward-looking statements: satisfaction of regulatory and other requirements; actions of regulatory bodies and other governmental authorities; changes in laws and regulations; issues with product quality, manufacturing or supply, or patient safety issues; and other risks identified and described in more detail in the "Risk Factors" section of Mallinckrodt's most recent Annual Report on Form 10-K and other filings with the SEC, all of which are available on its website. The forward-looking statements made herein speak only as of the date hereof and Mallinckrodt does not assume any obligation to update or revise any forward-looking statement, whether as a result of new information, future events and developments or otherwise, except as required by law.

Mallinckrodt is a global business that develops, manufactures, markets and distributes specialty pharmaceutical products and therapies. Areas of focus include autoimmune and rare diseases in specialty areas like neurology, rheumatology, nephrology, pulmonology and ophthalmology; immunotherapy and neonatal respiratory critical care therapies; analgesics and gastrointestinal products. To learn more about Mallinckrodt, visit

Mallinckrodt uses its website as a channel of distribution of important company information, such as press releases, investor presentations and other financial information. It also uses its website to expedite public access to time-critical information regarding the company in advance of or in lieu of distributing a press release or a filing with the U.S. Securities and Exchange Commission (SEC) disclosing the same information. Therefore, investors should look to the Investor Relations page of the website for important and time-critical information. Visitors to the website can also register to receive automatic e-mail and other notifications alerting them when new information is made available on the Investor Relations page of the website.

Rhonda Sciarra
Senior Communications Manager

Meredith Fischer
Chief Public Affairs Officer

Investor Relations      
Daniel J. Speciale, CPA
Investor Relations and Strategy Officer

Mallinckrodt, the "M" brandmark and the Mallinckrodt Pharmaceuticals logo are trademarks of a Mallinckrodt company. Other brands are trademarks of a Mallinckrodt company or their respective owners. © 2018 07/18

1 Barrington JW, Hansen RN, Lovelace B et al. Impact of Intravenous Acetaminophen on Lengths of Stay and Discharge Status after Total Knee Arthroplasty. Journal of Knee Surgery. 2018 Mar 7.
2 A range of values so defined that there is a specified probability that the value of a parameter lies within it.
3 Mont MA, Lovelace B, Pham A et al. Intravenous Acetaminophen May Be Associated with Reduced Odds of 30-Day Readmission after Total Knee Arthroplasty. Journal of Knee Surgery. 2018 May 7.


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