Written by Clay Smith
Acetaminophen (APAP) was not inferior to diclofenac or APAP+diclofenac for minor, acute extremity pain at 90 minutes.
Why does this matter?
A recent study of APAP for acute low back pain found it was no better than placebo at the same doses used in this study. But what about acute extremity pain? If APAP was as good as NSAIDs, this would be very helpful for patients with contraindications to NSAIDs, such as those with peptic ulcer disease or chronic kidney disease. Also, a study earlier this year found the combination of acetaminophen + ibuprofen 400mg was equal to an opiate at 120 minutes for sprains and extremity fractures.
Acetaminophen = NSAIDs
This was a multicenter RCT with about 180 per group with acute extremity contusions and sprains: APAP alone at a dose of 4,000 mg/day, diclofenac 150 mg/day, or APAP 4,000 mg/day + diclofenac 150 mg/day over the course of 3 days. They found APAP reduced pain by about 1 point on a numeric rating scale at rest and almost 2 points with movement at 90 minutes after the dose. Diclofenac alone or in addition to APAP did not offer significantly better pain relief. So for acute extremity pain, APAP was not inferior to NSAIDs, diclofenac specifically, nor was it synergistic at the 90-minute cutoff. However, given that 60% of patients had contusions, it may not be surprising that APAP was all that was needed in these very minor injuries.
Acetaminophen or Nonsteroidal Anti-Inflammatory Drugs in Acute Musculoskeletal Trauma: A Multicenter, Double-Blind, Randomized, Clinical Trial. Ann Emerg Med. 2018 Mar;71(3):357-368.e8. doi: 10.1016/j.annemergmed.2017.08.041. Epub 2017 Oct 14.
Peer reviewed by Thomas Davis.