Perioperative N-acetylcysteine: evidence and indications

Nonopioid analgesics serve to improve analgesia and limit side effects and risks of perioperative opioids. N-acetylcysteine (NAC), the primary treatment of acetaminophen toxicity, may have perioperative indications, including analgesia. NAC impacts glutathione synthesis, oxidant scavenging, glutamate receptor modulation and neuroinflammation. Potential perioperative benefits include arrhythmia prevention after cardiac surgery, decreased contrast-induced nephropathy, improved post-transplant liver function and superior pulmonary outcomes with general anesthesia. NAC may improve perioperative analgesia, with some studies displaying a reduction in postoperative opioid use. NAC is generally well tolerated with an established safety profile. NAC administration may predispose to gastrointestinal effects, while parenteral administration may carry a risk of anaphylactoid reactions, including bronchospasm. Larger randomized trials may clarify the impact of NAC on perioperative analgesic outcomes. PLAIN LANGUAGE SUMMARY Nonopioid mediations are important to help pain control after surgery and may decrease risks of opioids. N-acetylcysteine (NAC), the treatment of acetaminophen overdose, decreased inflammation and has other positive effects on the body that may help pain after surgery. Thus, NAC has been studied to prevent abnormal heart rhythms with heart surgery, help kidneys after surgery, improve the liver after liver transplant or other live surgeries and improve breathing after anesthesia. NAC may also decrease pain and the amount of pain medications needed after surgery. While NAC is generally well tolerated and considered safe, stomach upset can occur as can itching or asthma like reactions in certain patients. This review describes how NAC may improve pain, summarizes the other ways NAC may help a patient undergoing surgery, and describes potential side effects when NAC is given.