Back pain: Acetaminophen no better than placebos


A large-scale, rigorous study published in the Lancet found that the go-to, front-line treatment for back pain was no better than a placebo.

We did a multicentre, double-dummy, randomised, placebo controlled trial across 235 primary care centres in Sydney, Australia, from Nov 11, 2009, to March 5, 2013. We randomly allocated patients with acute low-back pain in a 1:1:1 ratio to receive up to 4 weeks of regular doses of paracetamol (three times per day; equivalent to 3990 mg paracetamol per day), as-needed doses of paracetamol (taken when needed for pain relief; maximum 4000 mg paracetamol per day), or placebo. Randomisation was done according to a centralised randomisation schedule prepared by a researcher who was not involved in patient recruitment or data collection. Patients and staff at all sites were masked to treatment allocation. All participants received best-evidence advice and were followed up for 3 months. The primary outcome was time until recovery from low-back pain, with recovery defined as a pain score of 0 or 1 (on a 0—10 pain scale) sustained for 7 consecutive days. All data were analysed by intention to treat. This study is registered with the Australian and New Zealand Clinical Trial Registry, number ACTN 12609000966291.

Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial [Dr Christopher M Williams PhD, Prof Christopher G Maher PhD, Prof Jane Latimer, Prof Andrew J McLachlan PhD, Mark J Hancock PhD c, Prof Richard O Day MD, Chung-Wei Christine Lin PhD/The Lancet]

(Image: Hydrocodone, Guian Bolisay, CC-BY-SA)

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  1. In 1983, Pearce and coworkers studied adults with any severity of migraine, defined using the Prensky and Sommer criteria in a 2-way crossover RCT. Recruited patients attended a headache clinic as outpatients. Patients received either 400 mg of ibuprofen or 900 mg of acetaminophen. Primary outcome was any pain reduction. After scoring each attack as mild, moderate or severe, 17/23 (74%) and 17/26 (65%) found that the average severity of headaches decreased equally from baseline with ibuprofen or acetaminophen, respectively.

    However, it does appear that ibuprofen is much better for specifically tension-related headaches:

    Schachtel and colleagues published an RCT involving adults. Patients with a moderate to severe tension headache in an unidentified setting received either 400 mg of ibuprofen, 1000 mg of acetaminophen or a placebo. The primary outcome was not specified. Among the 613 patients enrolled, 455 were analyzed. Using a 100-mm visual analog Headache Pain Intensity Scale, pain intensity scores were significantly lower at 0.5, 1, 2, 3 and 4 hours with ibuprofen than with acetaminophen (p < 0.01). Complete pain-free status was obtained for 63% of the patients in the ibuprofen group compared with 34% in those treated with acetaminophen (p < 0.01).

    Source

  2. The only thing it does for me is damage my liver. It doesn't help alleviate pain of any sort for me.

  3. Umm, no. That's not what it says.

    What it says under the heading "Interpretation", in the abstract linked, is:

    Our findings suggest that regular or as-needed dosing with paracetamol does not affect recovery time compared with placebo in low-back pain.

    [emphasis added]

    Please note the difference between "does not affect recovery time" and "is no better than."

    Shortening recovery time is not a painkiller's only effect - patients also take painkillers to reduce pain.

    Pain reduction can very, very useful even if it doesn't dial the pain all the way down to 0 or 1 "full recovery" levels - just reducing it from, say, 9 to 4 is incredibly useful - and the abstract does NOT say what effect, if any, it had on pain levels prior to full recovery - only that that it didn't shorten the time to full recovery.

    And frankly, I wouldn't really expect it to - it's a painkiller, not an anti-inflammatory or a muscle relaxant.

    Not really even sure why this was studied in the first place - acetaminophen may the "front line" painkiller, but only because it's the safest thing to give someone when they first present
    at the ER and the doc is uncertain of their history.

    After there's been time to fully evaluate the patient and her history, more effective painkillers and other more useful drugs are usually prescribed.

    At least IME, here in the USA.

  4. I thought the go-to, front-line treatment for back pain was drinking yourself stupid...

  5. I'm totally there with you guys. There is absolutely no upside to acetaminophen for me: does not mitigate any type of pain whatsoever, and it's bad for the liver.

    If its only real use is for fever, then why do medical personnel keep recommending it for various pain issues?

    I've gone back to using aspirin as a simple, cheap solution that works great for me.

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