Acetaminophen exerts no opioid-sparing effect

Intravenous (IV) acetaminophen does not effectively reduce opioid consumption in patients who have undergone surgery, according to a study.

Researchers conducted a systematic review of published randomized controlled trials to define the opioid-sparing effect of IV acetaminophen in different types of surgeries. The review included 37 studies, which involved a total of 44 treatment cohorts.

Compared with active- or placebo-control treatments, acetaminophen produced a substantial opioid-sparing effect in 14 comparisons (32 percent). However, it failed in less than half of the studies in each surgical category, with the exception of the hysterectomy and gynaecological surgery.

An opioid-sparing effect was more commonly seen in placebo-controlled comparisons (13 out of 28; 46 percent). On the other hand, IV acetaminophen produced an opioid-sparing effect in only one of 16 (6 percent) active-control groups.

Among the 16 active-control groups, opioid consumption was significantly greater among patients in the IV acetaminophen arm than the active comparator arm in seven cohorts and similar between the two arms in eight cohorts.

Given the results, the use of IV acetaminophen should only be considered in patients with contraindication to nonsteroidal anti-inflammatory drugs, the researchers said. This underscores a need to develop other more effective systemic adjuvant analgesic options for surgical patients.