Research on using cannabis for shingles is very limited, but some patients report positive effects from using it for neuropathic pain. This makes sense, since research shows that cannabis can be particularly helpful for treating this type of pain. The endocannabinoid system — with which cannabis interacts — is tasked with regulating pain signaling, so using cannabis may reduce the pain signaling involved in shingles-related neuralgia. While more research is needed, the evidence we do have suggests cannabis as a safe and effective treatment for this pain.
Research on shingles and cannabis
Research on cannabis for shingles has been extremely limited, but there is a long history of using cannabis to manage the condition. You can even find shingles listed as a use for cannabis as far back as 1851 in the United States Pharmacopoeia. These days, cannabis is used by some shingles patients on their own as a way to manage the painful neuralgia that is characteristic of the disease. But we still don’t have the kind of rigorous studies looking at shingles and cannabis that we’d need to make firm determinations about whether this use is effective.
Still, what we do have suggests that cannabis could be helpful.
- One small study on only eight participants looked at whether stimulating cannabinoid receptors could help reduce pain from facial neuralgia in shingles patients. They used a topical application — putting cannabinoid agonists directly on the face of the patients. The therapy brought on no adverse side effects for the patients involved, but did reduce pain for five of the eight patients in the study (62.5%), with an average reduction in pain of 87.8%. These results suggest that cannabis could ease pain for some shingles patients. Still, the low number of patients and lack of placebo controls limits the quality of this evidence.
That is the only study looking at cannabinoids and shingles specifically. Still, we can look at the research on using cannabis for pain, and neuropathic pain in particular.
- Pain is actually an extremely common reason that patients use cannabis. Surveys asking cannabis patients why they use cannabis have found that high percentages of patients report pain as their main reason for using cannabis. Some studies show positive results as high as 97% — and patients seem to be happy with the results. In a survey conducted by UC Berkeley, 81% of patients reported that cannabis alone was more effective at relieving their pain than opioids.
Of course, survey data is notoriously vulnerable to bias, so it’s also important to look into the clinical research on using cannabis for pain.
- For example, in 2017, the National Academies of Science and Engineering conducted a review on previous cannabis literature. Researchers reported that there is substantial evidence that cannabis is an effective treatment for chronic pain in adults, and tends to produce a moderate level of relief. Most of the research they reviewed was relevant to neuropathic pain specifically, so this is good news for shingles sufferers.
- Another 2017 review from Harvard University found “modest” evidence from clinical trials supporting the use of cannabis for pain, and even found evidence that cannabis use could help reduce opioid use when the two are used together.
- A 2018 review of using cannabis specifically for neuropathic pain also found evidence that cannabis could be effective. The authors explain that using low-dose cannabis, particularly when used sublingually or vaporized, can be a safe and effective option for neuropathic pain. But they point out that more rigorous research should be done to find out the best ways to utilize the many different forms of cannabis.
CBD and shingles
There is also research suggesting that CBD, a non-intoxicating cannabinoid in cannabis, can also offer pain-relieving benefits. This is partly because CBD is able to interact with our serotonin receptors to signal to the brain to reduce pain sensations. The World Health Organization recently did a full review on the medical literature on CBD and found that there is evidence to support the claim that CBD helps with pain. In fact, the WHO found that it was especially helpful for neuropathic pain — so it could be a helpful treatment for shingles.
It has also been found to be effective for pain when used in a topical formulation, which could be helpful for those who want to target a particular painful area — such as the face to combat facial neuralgia.
In addition, combining CBD with THC can have benefits. Studies show that the combination of these two cannabinoids can be more effective for pain relief than either one alone.
How cannabis works on shingles
The endocannabinoid system (ECS) exists in all vertebrates and helps regulate crucial functions such as sleep, pain, and appetite. The human body produces its own cannabinoids, which modulate and activate its various functions, but as its name suggests, the endocannabinoid system can also be modulated and activated by cannabinoids found in the cannabis plant. Because the entire system was only discovered in the past 30 years, scientists still have much to learn about the myriad ways cannabis affects the human body.
When it comes to shingles, there hasn’t been much research on how the ECS factors into the disease, specifically. But we do know that it is intimately involved in one particular symptom of shingles — neuropathic pain, or neuralgia.
This nerve pain relates to the endocannabinoid system because cannabinoid receptors CB1 and CB2 (which are activated by our natural cannabinoids and those in cannabis) are present in the nerves that are malfunctioning and causing pain in shingles. This means that stimulating these receptors could make an impact on the neuropathic pain.
In fact, one of the main roles of the endocannabinoid system is regulating pain sensation. When it is functioning normally, our natural cannabinoids activate CB1 when needed to reduce pain signals and our perception of pain. Stimulating CB1 receptors can even reduce our emotional response to pain by down-regulating the emotional pain response that comes up with physical pain.
Stimulating CB2 receptors can also reduce pain signaling. While scientists originally thought CB2 receptors were only found on immune cells, new evidence suggests that they are also present on nerve fibers and sensory neurons. Scientists now theorize that activating CB2 could mediate pain signaling through indirect activation of the opiate receptors — which can also reduce pain.
So while it’s unclear whether the ECS is involved in the progression of shingles, it is clear that it is involved in the severity of the neuropathic pain related to shingles. This has led some researchers to suggest that targeting the endocannabinoid system could be an effective way to reduce this painful neuropathy.
Potential side effects of cannabis use
Despite the positive potential for cannabis and shingles, there are some potential side effects to be aware of. Cannabis can cause a wide array of side effects such as respiratory discomfort like coughing and increased phlegm (when inhaled), temporary cognitive deficits, short-term memory loss, a racing heart, and impaired coordination.
It can also include bigger risk factors for some — such as increasing risk of psychosis for schizophrenic patients, or increasing the risk of certain cardiac conditions. For a minority of patients, it can lead to addiction.
In studies on cannabis and neuropathic pain, common negative side effects were sleepiness, dizziness, and mental confusion.
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