At one level, the concept of opioid tolerance seems fairly straightforward. Over any significant period of time, continued use of opioid drugs inevitably reduces the body’s autonomic response to the medications and higher doses are needed to achieve the same effect. Depending on the user’s situation, this decreased efficacy can result in long-term physical/psychological dependence, massive changes in brain chemistry, and death.
You can think of this as the ‘common sense’ conception of opioid tolerance. This is what we have learned through personal experience, pop culture, and the increased coverage of the opioid epidemic in nearly every media format on the planet. But while this description is fine as far as it goes, the fact is that it just doesn’t go far enough. In the following sections, you’ll find the accurate and in-depth information that the current opioid crisis requires.
What Exactly Is Opioid Tolerance
As most people know, opioid drugs are frequently used to treat moderate to severe pain in the clinical setting. Opioid drugs are one of the most popular recreational drugs in the United States as well, with some 230,000 people dying from opioid overdoses between 1999 and 2018. Significantly, there were approximately four times more opioid deaths in 2018 than occurred in 1999.
Increased tolerance to specific aspects of opioids has been the driving force behind these avoidable deaths. That’s why it is critical that we acquire a deeper understanding of the mechanisms involved in the development of drug tolerance.
The exact pharmacology that animates increased levels of tolerance is extraordinarily complex. Fortunately, we can formulate a very revealing summary of tolerance development without digging too deep into the human body’s complicated metabolic processes. Here are the three things that concerned persons need to know about this form of tolerance development:
- Broadly speaking, opioids have two classes of effects on the human body– pain relief or analgesia and negative side effects like nausea, gastrointestinal difficulties, and suppression of respiratory functioning.
- Increased tolerance to the desired analgesic effects happens very rapidly, while tolerance to the unpleasant side effects of long-term opioid use happens at a much slower rate. This is one of the keys to gaining a more nuanced understanding of the phenomenon of tolerance– the need/desire for the euphoric analgesic effects of opioids will still be there long after the body starts to resist them. Couple this certainty with the much slower development of negative side effects and it becomes clear why increased tolerance is unavoidable for anyone who uses opioids for an extended period of time.
- These first two facts lead us to a troubling but eye-opening conclusion. Simply put, the notions of both decision and choice begin to fall out of the opioid equation once users cross a certain dosage threshold.
Going Forward
As you can see, opioid tolerance and the tragic consequences that so often accompany it are undeniable physiological facts. As such, it will happen to anyone who uses opioid drugs for an extended period of time, regardless of the reasons behind their initial use. In other words, opioid drugs don’t care why someone started using them.
Whether the person is a recreational user ‘chasing the dragon’ of narcotic euphoria, or a cancer patient trying to increase their quality of life, they will come to need substantially higher doses to achieve the original effect and be exposed to the myriad dangers involved in opioid addiction. We will make little progress in the opioid battle until we internalize and apply this more nuanced conception.
External links:
1.) https://www.cdc.gov/drugoverdose/data/prescribing/overview.html
2.) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2628209/