Single doses of intravenous formulations of paracetamol (acetaminophen) to reduce pain after surgery in adults and children

Tzortzopoulou A, McNicol ED, Cepeda MS, Francia MBD, Farhat T, Schumann R

Published Online:

October 5, 2011

Pain is commonly experienced after surgical procedures and multiple medications are routinely used to control it. This review assessed data from 36 studies of participants (3896 in total) experiencing moderate to severe pain after various operations. It found that intravenous (IV) formulations of paracetamol (either IV propacetamol or IV paracetamol) provided pain relief for a period of four hours for about 40% of participants. Direct comparisons with other pain killers, such as morphine and anti-inflammatories, did not show any difference in effectiveness, although this may have been due to the small numbers of participants in these comparisons (i.e. the studies were not statistically powered to show a difference). IV propacetamol and IV paracetamol produced few side effects. However, participants receiving IV propacetamol complained of pain at the site their medication was infused at more often than those receiving placebo or IV paracetamol.

Abstract (click to read)

Background:

Paracetamol (acetaminophen) is the most commonly prescribed analgesic for the treatment of acute pain. It may be administered orally or intravenously. The efficacy and safety of intravenous (IV) formulations of paracetamol, IV paracetamol and IV propacetamol, compared with placebo and other analgesics, is unclear.

Objectives:

To assess the efficacy and safety of IV formulations of paracetamol for treatment of postoperative pain in both adults and children.

Search strategy:

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), MEDLINE (1950 to May 2010), EMBASE (1980 to 2010, Week 18), LILACS (1992 to May 2010) and reference lists of retrieved articles.

Selection criteria:

Randomized, double-blind, placebo- or active-controlled single dose clinical trials of IV propacetamol or IV paracetamol for acute postoperative pain in adults or children.

Data collection and analysis:

Two review authors independently assessed the risk of bias and extracted data. We contacted study authors for additional information. We collected adverse event information from the studies.

Main results:

Thirty-six studies (3896 participants) were included. Thirty-seven percent of participants receiving IV propacetamol/paracetamol experienced at least 50% pain relief over four hours compared with 16% of those receiving placebo (number needed to treat to benefit (NNT = 4.0; 95% confidence interval 3.5 to 4.8). The proportion of participants in IV propacetamol/paracetamol groups experiencing at least 50% pain relief diminished over six hours, as reflected in a higher NNT of 5.3 (4.2 to 6.7). Participants receiving IV propacetamol/paracetamol required 30% less opioid over four hours than those receiving placebo. However, this did not translate to a reduction in opioid-induced adverse events.

Meta-analysis of efficacy comparisons between IV propacetamol/paracetamol and active comparators (opioids or nonsteroidal anti-inflammatories (NSAIDs)) were either not statistically significant, not clinically significant, or both.

Adverse events occurred at similar rates with IV propacetamol or IV paracetamol and placebo. However, pain on infusion occurred more frequently in those receiving IV propacetamol versus placebo (23% versus 1%).

Meta-analysis did not demonstrate statistically significant differences between IV propacetamol/paracetamol and active comparators for any adverse event except a reduction in the rate of hypotension versus NSAIDs and a reduction in the rate of gastrointestinal disorders versus opioids.

Authors' conclusions:

A single dose of both IV propacetamol and IV paracetamol provides around four hours of effective analgesia for about 37% of patients with acute postoperative pain. Both formulations are associated with few adverse events, although patients receiving IV propacetamol have a higher incidence of pain on infusion than both placebo and IV paracetamol.

This record should be cited as:

Tzortzopoulou A, McNicol ED, Cepeda MS, Francia MBD, Farhat T, Schumann R. Single dose intravenous propacetamol or intravenous paracetamol for postoperative pain. Cochrane Database of Systematic Reviews 2011, Issue 10. Art. No.: CD007126. DOI: 10.1002/14651858.CD007126.pub2

Assessed as up to date:

July 26, 2011

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Primary Review Group:

Pain, Palliative and Supportive Care Group

Health topics:

Anaesthesia & pain control > Acute pain > Pharmacological treatment

Anaesthesia & pain control > Peri-anaesthetic/peri-operative care > Post-operative pain

Orthopaedics & trauma > Acute pain > Pharmacological treatment

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Single doses of intravenous formulations of paracetamol (acetaminophen) to reduce pain after surgery in adults and children

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