Acetaminophen is Good, But Morphine is Better

Much has been made recently of the risks and harms of opiates.  The main problem – sometimes they really do work.  Thanks to this study, we again confirm our prior conception of just how well they do work – at least for sciatica.

This trial randomized 300 patients with sciatica to intravenous morphine, paracetamol (acetaminophen), or placebo.  For obvious ethical concerns, all patients received fentanyl rescue at 30 minutes, as needed.  All groups started out around 80 on the pain VAS.  Placebo dropped patients to a mean of 66.  Paracetamol dropped patients to 41.  And morphine dropped patients to 24.  More interestingly, 80% of placebo needed rescue therapy – which implies 20% did not.  Then, 18% of acetaminophen received rescue therapy, followed by 6% of morphine.

So, while morphine is obviously statistically superior to paracetamol, the clinically important difference is less apparent.  The vast majority of patients will have enough relief from paracetamol that additional therapy is unneeded – and, in general, intravenous paracetamol is not likely to have quite the risk of adverse effects.

However, some of the generalizability of this study is limited, as many contexts attempt to manage this pain with oral medications, rather than intravenous.  And, this study may also only be generalizable to your patients based on how similar they are to the typical Emergency Department visitor in Turkey.

“Comparison of Intravenous Morphine vs Paracetamol in Sciatica: A Randomized Placebo Controlled Trial”