Kathleen Louden

October 24, 2013

SAN FRANCISCO — Using a combination of intravenous (IV) acetaminophen and opioid narcotics during tonsillectomy instead of opioids alone decreases a child's need for rescue analgesics, and is less expensive overall, a new cost-effectiveness study suggests.

"We actually found a savings by using an additional drug," lead investigator Rajeev Subramanyam, MD, from Cincinnati Children's Hospital Medical Center, told Medscape Medical News.

The intraoperative use of the combination, compared with IV opioids alone, resulted in a 3.3% reduction in events requiring rescue analgesics in the postanesthesia care unit, and saved the center $17.12 per patient, according to Dr. Subramanyam.

In the United States, 530,000 tonsillectomies are performed every year, which could mean a cost saving of $9 million.

"The routine use of IV acetaminophen as an adjunct to IV opioids during tonsillectomy, with or without adenoidectomy, in children should be considered a means to reduce the need for rescue analgesics and, in turn, reduce costs," he said.

Dr. Subramanyam reported first results from 139 patients in an oral poster presentation here at the American Society of Anesthesiologists (ASA) 2013 Annual Meeting.

 
We actually found a savings by using an additional drug.
 

Because children with sleep apnea — the most frequent indication for tonsillectomy — are very sensitive to narcotics, it is important to use opioid-sparing pain treatments in this population, Dr. Subramanyam noted.

IV acetaminophen (Ofirmev, Cadence Pharmaceuticals) was approved for use with adjunctive opioid analgesics by the US Food and Drug Administration (FDA) in 2010.

Earlier this year, the FDA issued a warning about the use of codeine in children undergoing tonsillectomy or adenoidectomy, after some children died because they had a genetic predisposition to rapidly metabolize codeine, which reached toxic levels in the body.

As part of an ongoing prospective pilot study, Dr. Subramanyam's team evaluated the cost-effectiveness of a regimen of IV acetaminophen and opioids in patients younger than 17 years undergoing tonsillectomy or adenotonsillectomy with inhaled anesthesia.

During surgery, 73 patients received IV acetaminophen plus opioids, and 66 patients received IV opioids alone.

The primary outcome was the cost-effectiveness of intraoperative pain treatment, determined by how often rescue analgesics were not needed in the postanesthesia care unit.

In addition, the researchers used decision analysis software to evaluate the probability of postoperative nausea and vomiting, pruritus, and respiratory depression.

They calculated the direct medical cost of the intraoperative IV analgesics, the rescue analgesics used, and the treatment of adverse events related to pain medications.

In the 2 groups, the only adverse effect requiring treatment was postoperative nausea and vomiting, which was minor, Dr. Subramanyam reported.

Although the medication cost was higher with the combination than with opioids alone, total direct costs — which included staffing, supplies, and facility use — were less with the combination ($73.48 vs $56.36 per patient).

The researchers attributed the cost savings largely to the finding that patients receiving IV acetaminophen had 3.3% fewer rescue analgesia events (relative risk, 0.95).

As the probability of using rescue analgesics increased, the marginal cost-effectiveness ratio of the combination treatment decreased, report researchers.

When rescue analgesia was required, narcotic-related adverse effects were 3.4% lower with the combination than with opioids alone. However, the need for nausea treatment was 15.1% higher with the combination.

Dr. Subramanyam cautioned that institutions with different direct costs will have different results. However, these findings will likely lead to more anesthesiologists using IV acetaminophen in children undergoing tonsillectomy, he noted.

Before any changes are made to clinical practice, more study in a larger number of patients is needed, said Mary Dale Peterson, MD, a pediatric anesthesiologist at Driscoll Children's Hospital in Corpus Christi, Texas.

Not Cost-Effective Enough

"It's disappointing to me that there is only a 3% difference in the need for rescue analgesics," she told Medscape Medical News.

The cost of IV acetaminophen is still a consideration, said Dr. Peterson, who is assistant treasurer for the ASA and was not involved in the study.

The IV formulation costs more than oral acetaminophen, according to a review published in January 2012 in Pharmacy Times.

Dr. Subramanyam noted that, in this study, a 100-mL vial of IV acetaminophen cost $15.38, and that it is often difficult for children to swallow oral painkillers after tonsillectomy.

Dr. Peterson asked whether the researchers used ondansetron and dexamethasone intraoperatively, and whether the 2 groups received similar amounts of the drugs.

Dr. Subramanyam explained that they did administer both medications during tonsillectomy, but they did not compare mean drug doses between groups.

This study was funded by a grant from the ASA Committee on Professional Diversity. Dr. Subramanyam and Dr. Peterson have disclosed no relevant financial relationships.

American Society of Anesthesiologists (ASA) 2013 Annual Meeting: Abstract 1240. Presented October 12, 2013.

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