The Role of Intravenous Acetaminophen in Acute Pain Management

A Case-Illustrated Review

Chris Pasero, MS, RN-BC, FAAN; Daphne Stannard, PhD, RN, CCRN, CCNS, FCCM


Pain Manag Nurs. 2012;13(2):107-124. 

In This Article

Conclusion and Nursing Implications

Intravenous acetaminophen is a nonopioid non-NSAID analgesic for the management of mild to moderate pain or as part of a multimodal pain treatment strategy with adjunctive opioid analgesics for moderate to severe pain. When used as recommended, IV acetaminophen is a safe addition to the current available analgesics. Before administering IV acetaminophen, however, nurses should be aware of the patient's use of both prescription and nonprescription medications that contain acetaminophen to avoid exceeding the maximum daily dose of acetaminophen. After administration of IV acetaminophen, the nurse must explain to patients the importance of not exceeding the maximum daily dose of acetaminophen with prescription and nonprescription medications that the patient may take after discharge.

Supplied as a single-dose vial with a concentration of 1,000 mg/100 mL, IV acetaminophen requires no reconstitution or dilution and is administered by 15-minute vented infusion. Simple weight-based dose calculation is necessary for children aged 2–12 years and anyone aged ≥13 years weighing ≤50 kg. IV administration provides a more rapid onset of analgesia with more predictable pharmokinetics parameters than oral or rectal acetaminophen administration. The analgesia achieved with IV acetaminophen administration can be subsequently maintained by oral delivery. No dose adjustment is necessary when converting between oral and IV acetaminophen dosing in adults and adolescents.

Intravenous acetaminophen has broad compatibility with other agents making it an excellent choice as an adjunct to other analgesics, such as NSAIDs and opioids, where synergy through complementary mechanisms of action may be clinically useful in multimodal analgesic regimens. A major advantage of IV acetaminophen is that it reaches a significantly higher (70%) maximum concentration faster (at the end of the 15-minute infusion) than when the drug is given orally or rectally (>45 minutes), and this is accomplished without compromising the safety profile of the drug. Other benefits are that the use of IV acetaminophen may reduce opioid consumption, minimize the incidence of opioid-related adverse events, improve pain relief, increase patient satisfaction, expedite mobilization and rehabilitation, and reduce health care costs. Because of its efficacy, safety, lack of clinically significant drug interactions, and lack of the adverse effects associated with other analgesics, IV acetaminophen is an attractive component of a multimodal analgesic treatment plan. When patients are able to tolerate oral intake, they may be moved from IV to oral acetaminophen to maintain the predictable analgesia established by the IV route.


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