Study Shows Safety of Pharma-Grade CBD for Myocarditis

An oral formulation of pharmaceutically manufactured cannabidiol (CBD) that targets inflammatory pathways in myocarditis and pericarditis has been shown to be as safe as placebo in not elevating cardiovascular risks, results of a prospective trial have shown.

The placebo-controlled trial enrolled 89 people with a history of cardiovascular disease (CVD) and/or at least one major risk factor for the condition who had been hospitalized for noncritical COVID-19.

“There are 45 or so who received pharmacologically produced CBD who had no increase in overall or cardiovascular adverse events, and in particular there was no prolongation of the QT interval,” Leslie Cooper Jr, MD, chair of cardiovascular medicine at Mayo Clinic Florida in Jacksonville, Florida, told Medscape Medical News.

Cooper presented a poster on the study at Heart Failure Association of the European Society of Cardiology (HFA-ESC) 2025. The findings confirmed the safety of CBD doses up to 7.5 mg/kg twice daily used in the ARCHER trial in myocarditis and the MAVERIC trial in pericarditis, Cooper said.

Study Shows Safety Signal

The researchers designed the study during the COVID-19 pandemic to evaluate if people hospitalized for noncritical COVID-19 with a history of or a risk factor for CVD were also at an increased risk for cardiac inflammation, Cooper said. The study was stopped early because the pandemic ended.

“The findings were underpowered for efficacy, but they did support a safety signal,” he said.

The study found no significant differences in adverse events between the CBD and no-CBD groups. For example, the rate of gastrointestinal disorders was 22.2% in the CBD group and 20.5% in the placebo group. Nervous system disorders were observed in 17.8% of CBD patients vs 18.2% of placebo patients. Eleven percent of CBD patients had respiratory, thoracic, and mediastinal disorders compared with 9% of placebo patients.

The rates of cardiac adverse events were also similar between the two groups. No patients in the CBD group vs three (6.8%) of those in the placebo group had tachycardia. One case of atrial fibrillation, cardiac failure, left ventricular hypertrophy, and pericardial effusion was observed in the CBD group vs none in the placebo group. One patient in the placebo group vs none in the CBD group had atrial flutter.

Most cases of myocarditis are mild and resolve spontaneously without long-term consequences, Cooper said. However, about 25% of cases have significant cardiovascular sequelae, including arrhythmias and heart failure. “We know, based on clinical grounds, how to identify those complex patients who are probably going to have a rocky long-term course,” he said.

New Treatments Needed

While one drug, rilonacept (Arcalyst), has been approved for the treatment of recurrent pericarditis, no approved drugs for myocarditis exist.

New treatments are also needed for cardiomyopathy. Bettina Heidecker, MD, head of Heart Failure and Cardiomyopathy at the German Charité Heart Center in Berlin, Germany, told Medscape Medical News, said current therapies such as corticosteroids and other immunosuppressants carry long-term risks such as osteoporosis, metabolic disorders, infections, and organ toxicity, 

“A pharmaceutically standardized CBD formulation could offer a targeted anti-inflammatory approach with a more favorable side effect profile,” Heidecker told Medscape Medical News. “This would be particularly beneficial for younger or lower-risk patients, or those in whom prolonged immunosuppression is problematic.”

Heidecker said the new data provide a rationale for continued investigation of CBD in myocarditis and pericarditis. “It will be exciting to investigate how individual patients respond to CBD, particularly early in the treatment course,” she said.

Heidecker and her team in Berlin have been studying the utility of noninvasive magnetocardiography to detect myocardial inflammation and monitor response to anti-inflammatory therapy with the hope that the approach “may help identify early responders and guide personalized treatment strategies with CBD.” 

The trial was funded by Cardiol Therapeutics. Cooper is a consultant to Cardiol Therapeutics. Heidecker holds patents for RNA-based diagnostics in myocarditis and holds pending patents on magnetocardiography for diagnosing cardiomyopathy. She reported financial relationships with Biomagnetik Park Hoilding, Pfizer, and AstraZeneca.

Richard Mark Kirkner is a medical journalist based in Philadelphia.