Recurrent pericarditis can be associated with significant health challenges and reduced quality of life, making safe and effective treatment options vital.
As interest in medical cannabis continues to expand, a recent phase II clinical trial aimed to understand the safety of pharmaceutically manufactured cannabidiol (CBD) in the treatment of this debilitating disease.
Key Takeaways:
- The study. A Phase II, open-label clinical trial published in Journal of the American Heart Association, 2026 assessed changes in pericarditis pain scores and C‐reactive protein levels, as well as the occurrence of adverse events.
- Tolerability. CBD was generally well tolerated in most patients, with only one serious adverse event reported in one patient.
- Pain. Changes in chest pain scores were observed between baseline and Week 8, with reductions continuing into the extended period up to 26 weeks.
- C-reactive protein levels. CBD was associated with changes in C-reactive protein levels in the majority of patients.
What is Recurrent Pericarditis?
The pericardium is a thin sac around the heart. Pericarditis means that sac has become inflamed. It often follows a viral infection.
The main symptom is sharp chest pain. It can spread to the shoulder, arm or tummy, and often feels worse when lying flat or breathing deeply.
Most people recover with rest and anti-inflammatory medicines. But around 3 in 10 people have the problem come back after their first episode. This is called recurrent pericarditis. As many as half of those people go on to have several more episodes. Research shows this can have a marked effect on quality of life.
Why are researchers studying CBD for pericarditis?
Cannabidiol (CBD) is one of many compounds made by the cannabis plant.
Laboratory research suggests CBD can dampen down one part of the immune system, known as the NLRP3 inflammasome. That same pathway is thought to drive the inflammation in recurrent pericarditis, and several existing treatments work by blocking it. In mice, CBD reduced pericardial thickening and fluid build-up.
Laboratory and animal findings often do not carry across to people. Testing in humans is exactly why trials like this one are done.
To investigate this potential further, the authors of a recent phase II clinical trial, published in the Journal of the American Heart Association, assessed the outcomes of patients with symptomatic recurrent pericarditis given pharmaceutically manufactured CBD.
What did the study look at?
Researchers enrolled 27 adults who still had symptoms despite standard treatment. Most were already taking colchicine (85%), anti-inflammatory painkillers (67%) or steroids (41%). Before joining, they had lived with pericarditis for around 3 years and were having about 6 flare-ups a year.
Everyone received the trial medicine as an oral solution, with the dose increased gradually. For the first 8 weeks they kept taking their usual medicines. Those who continued into the extension period then had those medicines gradually reduced and stopped.
Participants scored their worst chest pain each day from 0 to 10. Blood tests measured C-reactive protein, a marker of inflammation.
What did the trial find?
Chest pain. Average worst pain fell from about 6 out of 10 at the start to about 2 out of 10 at week 8. Half of participants reached a score of 2 or less within 5 days. Scores stayed low to week 26, averaging about 1.5 out of 10.
Inflammation. Ten people had a raised C-reactive protein level at the start. Eight of them had a normal level by week 8. The other two both had normal levels by the end of the trial.
Flare-ups. Of the 24 people who continued into the extension period, 17 had no flare-up while their other medicines were reduced. Across the group, flare-ups fell from around six a year before the trial to around one a year during it. Flare-ups during medicine reduction were more common in people who had been taking steroids.
What side effects were reported?
Side effects were common. The most frequent were diarrhoea (15 of 27 people, usually settling on its own), chest pain (10 people) and rash (8 people). Nausea, tiredness, tummy discomfort and headache each affected 4 to 5 people.
Three people stopped the medicine because of side effects. Two people had a serious side effect. In one, this was a severe drug reaction. Investigators thought it was possibly related to the trial medicine. That person was also taking celecoxib, a painkiller already known to cause this reaction.
Heart rhythm tracings showed no concerning changes, and no participant reported thoughts of self-harm.
What does this trial actually tell us?
It tells us that a pharmaceutical CBD solution was tolerated by most people in this small group, and that pain scores and inflammation markers fell over the study.
It does not tell us that CBD caused those improvements, because:
There was no comparison group. Nobody received a placebo, so we cannot know what would have happened without the medicine.
Everyone knew what they were taking, which can influence how people rate their own pain.
The group was small and not diverse. All 27 participants were White.
Pericarditis often settles by itself, so some improvement would be expected anyway.
The trial was funded by the company developing the medicine, and several researchers hold paid advisory roles with pharmaceutical companies. They disclosed this openly.
The researchers say larger randomised trials with a placebo group are needed. One phase 3 trial is now underway.
What this means for people in the UK
The medicine tested is not the same as a shop-bought CBD product. It was pharmaceutical grade, given at high doses calculated by body weight, under close medical supervision. High-street CBD oils are regulated as foods, not medicines, and are not equivalent.
CBD is not a licensed treatment for pericarditis in the UK or anywhere else. This trial does not change that.
Pericarditis is not treated with medical cannabis in the UK. Your care should be led by your GP and cardiology team. Please do not stop or change any prescribed medicine without speaking to them first.
Frequently Asked Questions
Does CBD treat pericarditis?
No treatment claim can be made. CBD is not licensed for pericarditis anywhere. One small phase 2 trial has reported encouraging early results, but it had no comparison group and cannot show cause and effect.
Is CBD safe?
CBD is generally well tolerated in clinical studies, but it is not free of side effects. Diarrhoea, nausea, tiredness, rash and changes in liver blood tests are all recognised. CBD can also interact with other medicines, including some blood thinners and epilepsy medicines. Discuss it with a doctor or pharmacist who knows your full medicine list.
Does CBD make you high?
No. CBD is non-intoxicating. Tetrahydrocannabinol (THC) is the compound in cannabis which can cause euphoria when taken at sufficient doses. The product used in this trial contained no detectable THC.
Is CBD legal in the UK?
CBD products sold as food supplements are legally available, subject to novel food rules and a strict limit on controlled cannabinoid content. Medicines containing CBD are a separate category, available on prescription only, from a specialist doctor, for specific conditions.
Was this a large trial?
No. It enrolled 27 people. Trials this size check safety and decide whether a larger trial is worth running. They are not designed to prove a treatment works.
About Curaleaf Clinic
Curaleaf Clinic is a UK clinic providing specialist assessment for a defined range of conditions where conventional treatments have not worked well enough. Medical cannabis is prescription-only in the UK and most products are unlicensed. Any prescribing decision is made by a specialist doctor, case by case, after a full review of your medical history. A consultation does not mean a prescription will be issued.
Pericarditis is not among the conditions we assess for medical cannabis treatment.
To see which conditions we do assess, read about our clinic.
