Monique van Velzen on chronic pain and medicinal cannabis

Research into chronic pain and its treatment is urgent, because the burden of disease is high. According to researcher Monique van Velzen, one in five adults suffers from some form of chronic pain. Van Velzen was (and is) involved in different scientific studies into medicinal cannabis and chronic pain. On August 12, she was a guest during the third webinar of the Bedrocan Series.

Monique van Velzen is an assistant professor and research coordinator at the Leiden University Medical Center. She conducts team research into chronic pain and – ultimately – the most appropriate way to treat people with chronic pain. She is also a board member of the Institute for Medicinal Cannabis (see below).

Research into chronic pain and its treatment is urgent, because the burden of disease is high. According to Van Velzen, in the Netherlands alone, one in five adults suffers from some form of chronic pain, and this is no different in other countries.

‘Pain is an emotion’

In addition, chronic pain is a difficult condition to describe, says Van Velzen: “In a sense, pain is an emotion; it is often dependent on the situation of the moment and therefore subjective. This does not detract from the seriousness of the complaints, because many patients with chronic pain suffer from this in daily life; work is made more difficult, sleep is sometimes bad, people become depressed and/or become socially isolated. That makes chronic pain a very serious condition with a lot of impacts.”

The treatment of chronic pain is not easy either. Van Velzen: “There are medicines, such as anti-epileptics, anticonvulsants and opioids, but they all have serious side effects. You have to ask yourself whether this is desirable in long-term treatment because in some cases, the remedy is ultimately worse than the disease.”

‘Cannabis could be an alternative or addition’

That was also the reason for the LUMC Anasthesia & Pain Research Unit, led by Van Velzen and Professor Albert Dahan, to investigate whether medicinal cannabis could be an alternative or addition. “We chose fibromyalgia patients, a large group of patients with pain complaints throughout their body. Pain complaints that are also difficult to treat” says Van Velzen. “We know through various channels that many of those patients turn to cannabis as a pain reliever.”

That’s why we wanted to know if it is effective and what the side effects are. We have done a proof of concept study, a so-called randomized, double-blind, placebo-controlled four-way cross-over study. We wanted to use cannabis varieties whose composition – also in the longer term – is always the same so that you can make statements about effect and side effect. This is how we arrived at standardised medicinal cannabis, which is available on prescription from Dutch pharmacies. These were administered to the subjects by vaporizing.”

Fibromyalgia patients

The study revealed that fibromyalgia patients might benefit from medicinal cannabis, especially the products Bedrocan® and Bediol®. “We saw the most effect with varieties that were slightly higher in THC. But we also saw that those varieties produced the most side effects. This was already expected as some doses were given to people who are not used to using cannabis. In the long run, however, these two varieties seem to work best for fibromyalgia patients.”

‘Chronic pain requires chronic treatment’

The study, which was completed in 2018, was followed up fairly quickly. “Chronic pain requires chronic treatment, so we restarted a study that focuses on side effects. We use the Bediol variety, which is used by patients for a period of six weeks. We look at how these patients tolerate the drug. Are there any side effects? Does the use of this drug fit in their lives, also in the longer term? And how does that compare to the use of oxycodone, which is widely prescribed but also has many side effects and is therefore not ideal in the long term?”

Side effects with oxycodon

That study is currently underway, and conclusions cannot yet be drawn, although Van Velzen indicates that some expected side effects of both medicinal cannabis and opiates have now been noted. “We see the typical side effects, with oxycodone and with Bediol®. We do not yet know whether there is a difference between the groups.”

The final result of the study is expected in the course of 2022, and in the meantime the Leiden Anesthesia & Pain Research Unit, together with the Centre for Human Drug Research (CHDR), will conduct research into medicinal cannabis in patients with neuropathic pain. The research group has received a subsidy of 1.9 million euros from the Dutch government to research the most optimal ratio of THC and CBD for pain relief. And here, too, side effects will be looked at. In addition, the research group wants to further investigate patients’ processing of pain in the brain so that treatment – ​​with an appropriate dose of THC/CBD – can be tailored to this. These are lengthy studies, but the progress can be followed on the Dutch website Samentegenpijn.nl.

You can watch Bedrocan Series with Monique van Velzen here.