The Disadvantages of Opioids as Painkillers

by Sahil Rawal (’19)

Fig. 1: Morphine is an opioid that has been used as a painkiller.

Opioids are one of the most commonly used painkillers in the United States. They have been shown to bind to opioid receptors and reduce the feeling of pain. However, there have been very few, if any, studies conducted that prove the negative aspects of opioids and how they may not actually relieve pain as well as we once believed.

Dr. Grace and his team of researchers from the Department of Psychology at the University of Colorado set out to see if morphine, a type of opioid, had a negative effect on rats. The study created two groups of rats, both with chronic nerve pain, and treated one with morphine and left one untreated. The results from the study showed that the chronic pain of the morphine induced group was worse than the group without the morphine, and the pain actually worsened for the morphine group for months afterwards. The combination of nerve injury and the morphine activated cascade signaling from interleukin-1beta caused this increase in pain, and supports the claim that opioids are not optimal painkillers.

Future studies need to be done to corroborate these results, but this study sheds light on a concept that physicians and patients alike had wrong for a very long time.



  1. M. Grace, Morphine paradoxically prolongs neuropathic pain in rats by amplifying spinal NLRP3 inflammasome activation. Proceedings of the National Academy of Sciences of the United States of America 113 E3441-E3450 (2016). doi: 10.1073/pnas.1602070113.
  2. Image retrieved from:

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