Summary: Studies suggest that cannabis does not alter pain tolerance, so it holds up for long-term use in chronic pain. Opioids work quite well for pain. But over time they raise pain sensitivity, an effect called opioid-induced hyperalgesia. So people using opioids for pain need higher doses for relief, which raises the risk of addiction and overdose. Because of the ongoing opioid epidemic, researchers are looking for safer ways to treat chronic pain that still work.
Opioids are among the strongest painkillers and have been used in medicine for a long time. But because of the opioid epidemic in the US, many health experts now look for safer options. Many of these options may not replace opioids. But they might help cut opioid use, and they may work even better in certain health conditions.
One option worth exploring is cannabis. Medical cannabis has also been used for pain for a long time. But cannabis is safer by comparison. Also, many states have even started to legalize recreational cannabis. So it matters even more to understand its health benefits and its role in pain care.
Can opioids make pain worse over time?
Doctors have long known that opioids can even raise pain sensitivity in many regular opioid users. This effect is called opioid-induced hyperalgesia (OIH). It is a paradox. People use opioids to get past severe pain. Yet opioids may raise pain sensitivity.
It means that people who use opioids for a long time may stop responding to them. They may need higher doses to get past the pain. But higher doses or stronger opioids mean a greater risk of side effects and misuse. It is quite likely that this effect is partly to blame for opioid addiction.
Does cannabis cause hyperalgesia the way opioids do?
Now, though, new studies suggest that cannabis could be a safer option in many cases. It has shown it works for chronic pain. More important, people can safely use cannabis for a long time without raising the dose, because it does not appear to cause hyperalgesia like opioids.
Interest in cannabinoids (the active compounds in cannabis) has grown in recent years. Also, some compounds in the cannabis plant, like cannabidiol, are now sold without a prescription and are safe for long-term use. Doctors think opioids’ pain-sensitizing effect pushed doctors to use higher doses. They think that has added to opioid addiction and overdose deaths. Cannabinoids, by contrast, are much safer.
In the study, doctors enrolled people who used cannabis more than three times a week and compared their pain sensitivity with people who did not use cannabis at all. They used the cold-pressor task, in which people put their hands in cold water, to test how well each person could tolerate pain. They found that cannabis users did not show increased pain sensitivity, which is often seen in opioid users. Doctors say this is an important difference between the two substances. It further shows that cannabis is a safer option for managing chronic pain when compared to opioids.
Of course, it is still early, and there is much to learn about cannabis so we do not repeat old mistakes. Still, these studies are encouraging. And cannabis is not new to medicine or to people. A huge amount of safety data already exists on long-term cannabis use for many medical conditions. Still, this is one more step toward safer alternatives to opioid medication.
Frequently asked questions
What is opioid-induced hyperalgesia?
Opioid-induced hyperalgesia (OIH) is a paradox. The drug taken to get past severe pain makes the body more sensitive to pain over time. Doctors have known about it for a long time in regular opioid users. It means a person on opioids may stop responding to their usual dose. The pain can feel worse even though the medicine has not changed.
Why do people on opioids need higher doses over time?
Because opioids raise pain sensitivity with long use, the same dose stops working. A higher dose or a stronger opioid is then needed for the same relief. Each step up carries a greater risk of side effects, misuse, addiction and overdose. Doctors think this cycle of rising doses has added to the opioid epidemic and to overdose deaths.
Does cannabis make pain worse the way opioids can?
In the study described here, it did not. People who used cannabis more than three times a week were compared with people who did not use it at all. The cannabis users did not show the increased pain sensitivity often seen in opioid users. That means cannabis can be used for a long time for pain without needing to keep raising the dose.
How do researchers measure pain tolerance?
The study on this page used the cold-pressor task. People put their hands in cold water, and researchers measure how well they tolerate the pain. That let the researchers compare pain sensitivity between people who used cannabis more than three times a week and people who did not use cannabis at all.
Dr. Gurpreet Singh Padda, MD, MBA, MHP
