On Opioids

Vicodin, Lortab, Oxycontin, morphine… They are the source of all relief and of all ills. Of course, I exaggerate, but judging by the discourse around opioid deaths, we appear to be in a life-or-death struggle with these classes of medications. I would not presume to tell someone whether they should take opioids for pain or not, but there is clearly a need to shed more light on these drugs, especially their promises and their perils.

Opioids are a term derived from opiates which is a term derived from opium. They aren’t new compounds, opium has been used recreationally and medically for thousands of years. The difference between opioid and opiates is that opioids generally refer to synthetic drugs, like Oxycontin and Dilaudid while opiates refer to more “natural” drugs like morphine. Functionally, they aren’t any different. Both opiates and opioids work on the opioid receptors in the nervous system. Their binding to this receptor leads to their analgesic effect. This binding also leads to a plethora of other issues, especially in the brain’s reward system. Adverse effects include constipation, drowsiness, respiratory depression, nausea and vomiting, paradoxical increased pain (hyperalgesia), hormone imbalance (e.g., decreased testosterone), and addiction.

With all those possible adverse effects, why would anyone want to use opioids? Well, all the medications we have for pain work to some extent, but not as well as we want. They aren’t their to get rid of the pain, but to stave it off for a little while. The truth is, pain is not very well-understood. For a lot of people, opioids work very well for acute pain, as the body eventually resolves the injury. It’s when pain becomes chronic that the rationale for opioids become more fuzzy. Guidelines, like the CDC’s, state that there is no evidence for the efficacy of long-term use.  That does not mean that opioids are ineffective in the long-term, but that there are very few studies looking at opioid use beyond, say, a year.

The other elephant in the room is addiction. We have observed that it is not predictable and that even one day’s exposure to opioid can incur problematic behavior. Although relatively small compared to the entire opioid-using population, plenty of people abuse opioids or have overdosed, sometimes fatally. Estimates are hard to come by. What is the risk of addiction after one week’s work of opioid usage? One month? One year? There are estimates of 3-19% abuse for those on chronic opioid therapy (Edlund et al. 2010). In my own studies, I’ve seen rates of around 4% among all opioid users (they would probably be higher among chronic users). However, these estimates are based on small clinical samples and take place in various environments. Still, if you apply those percentages to the entire US population, the numbers would still be in the millions.

You must also consider tolerance and dependence. Once tolerance develops, you need to take more opioids to experience the same amount of pain relief. The higher the dose, the greater the risk. Dependence is characterized by the presence of withdrawal symptoms after opioids are curtailed or stopped. These symptoms can last for months or even years after discontinuation. That’s one reason for the large amount of relapse.

There are many aspects around the use of opioids (dose conversions; development of opioids with different mechanisms of action; Are these legal prescriptions, stolen prescriptions, or illicit opioids that are killing people?; Who is to blame for opioid deaths? Should anyone be blamed?). Ultimately, though, it comes down to weighing the risks and benefits, as with all medications. Consider the alternatives (although NSAIDs come up with a host of their own issues!). To do that we need more research, on opioids, on chronic pain, and on addiction.

Summary: Opioids are useful for pain relief, but come with a host of their own issues. Consider whether the risks (adverse effects and addiction) outweigh the benefits (pain relief).

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