Opioid-Sparing Effects of IV Acetaminophen for Patients Undergoing Surgery

Abstract

What Is the Issue? Opioids are often used to help manage postoperative pain. However, their consumption can cause side effects, in addition to the risk of developing dependence with long-term use. Acetaminophen is an alternative analgesic that may provide opioid-sparing benefits for patients undergoing surgery (e.g., the need for patients to use opioids later), but there is a lack of synthesized evidence to confirm. Acetaminophen is available in different formulations, such as IV, oral, and rectal. However, there is uncertainty around the benefits of using 1 formulation over another perioperatively. What Did We Do? To inform decisions about IV acetaminophen, we sought to identify and summarize literature comparing the effectiveness of IV acetaminophen to alternative analgesics (i.e., nonsteroidal anti-inflammatory drugs [NSAIDs]), alternative formulations (i.e., oral or rectal acetaminophen), or placebo for reducing opioid consumption in patients undergoing surgery. A research information specialist conducted a literature search of peer-reviewed and grey literature sources published between January 1, 2019, and January 9, 2024. The search was limited to English-language documents. One reviewer screened articles for inclusion based on predefined criteria. To investigate the true effect of IV acetaminophen, we excluded studies with any intraoperative opioid use. What Did We Find? For adult patients undergoing elective hip surgery, there may be no significant differences in cumulative opioid use between postoperative IV and oral acetaminophen (1 randomized controlled trial). For patients undergoing elective cesarian delivery, postoperative IV acetaminophen may result in a decrease in total morphine consumption after surgery compared to placebo (1 randomized controlled trial). For adult patients undergoing lumbar disc surgery, there may be no significant differences in total morphine consumption for patients receiving intraoperative IV acetaminophen compared to placebo (1 systematic review with 1 relevant RCT). We did not find any studies comparing the opioid-sparing effects of IV acetaminophen to NSAIDs that met our criteria for this review. What Does It Mean? Limited evidence from this review suggests that the opioid-sparing effect of IV acetaminophen may vary across types of surgery when compared to placebo. Additionally, IV acetaminophen may not offer additional opioid-sparing benefits compared to oral administration. However, we require more comprehensive research with rigorous methodological approaches to understand this topic better. Relative to opioids, IV acetaminophen has a preferable side effect profile, including a low risk of dependence; therefore, decision-makers may wish to consider using this formulation in the surgical or postsurgical setting.