Continuous Multimechanistic Postoperative Analgesia: A Rationale for Transitioning from Intravenous Acetaminophen and Opioids to Oral Formulations

Abstract

Good surgical outcomes depend in part on good pain relief, allowing for early mobilization, optimal recovery, and patient satisfaction. Postsurgical pain has multiple mechanisms, and multimechanistic approaches to postoperative analgesia are recommended and may be associated with improved pain relief, lowered opioid doses, and sometimes a lower rate of opioid-associated side effects. Acetaminophen (paracetamol) is a familiar agent for treating many types of pain, including postsurgical pain. Oral acetaminophen has been shown to be safe and effective in a variety of acute pain models. Combination products using a fixed-dose of acetaminophen and an opioid have also been effective in treating postsurgical pain. Combination products with acetaminophen have demonstrated an opioid-sparing effect, which inconsistently results in a reduced rate of opioid-associated side effects. Intravenous (IV) acetaminophen and an opioid analgesic administered in the perioperative period may be followed by an oral acetaminophen and opioid combination in the postoperative period. Transitioning from an IV acetaminophen and opioid formulation to a similar but oral formulation of the same drugs appears to be a reasonable step in that both analgesic therapies are known to be safe and effective. For postsurgical analgesia with any acetaminophen product, patient education is necessary to be sure that the patient does not concurrently take any over-the-counter products containing acetaminophen and accidentally exceed dose limits.

Intravenous vs Oral Acetaminophen as an Adjunct to Multimodal Analgesia After Total Knee Arthroplasty: A Prospective, Randomized, Double-Blind Clinical Trial

“…Multiple studies have shown reduced pain scores and decreased postoperative opiate consumption in surgical patients receiving either formulation of acetaminophen when used as a component of a multimodal approach in various surgical settings [3, 6, 16]. A majority of these studies administered acetaminophen pre-operatively, whereas in our study, it was administered postoperatively.…”

Randomized Trial of Adding Parenteral Acetaminophen to Prochlorperazine and Diphenhydramine to Treat Headache in the Emergency Department

“…20. Additionally, IV acetaminophen does not undergo first-pass metabolism in the liver, reducing hepatic exposure to acetaminophen and thus diminishing the potential for hepatic injury 16,19,21…”

Impact of Intraoperative Acetaminophen Administration on Postoperative Opioid Consumption in Patients Undergoing Hip or Knee Replacement

“…In addition to the ASA guidelines, other sources have advocated for a multimodal approach to postoperative analgesia. 13,14 Intravenous (IV) acetaminophen is one of the medications utilized in a multimodal analgesia regimen. 15 Acetaminophen has long been available in the United States as an oral or rectal formulation.…”