The Medical Cannabis Access Programme in Ireland currently offers access to cannabis for patients suffering from one of three specific conditions when other treatments have not been effective.

The three conditions are:

1. Spasticity (stiff and/or rigid muscles) associated with multiple sclerosis
2. Nausea and vomiting associated with chemotherapy
3. Severe epilepsy

An evidence review was carried out by the Health Research Board (HRB) to assist a Department of Health review of the current Medical Cannabis Access Programme and evaluate the suitability of cannabis-based products for various medical conditions.

Findings

The HRB (Health Research Board) discovered evidence supporting the use of prescribed medicinal cannabis for certain conditions for which it is currently approved in Ireland. These include nausea and vomiting in cancer patients and spasticity in individuals with multiple sclerosis.

Additionally, there was significant evidence indicating a benefit for neuropathic or nerve pain, which can arise from conditions such as multiple sclerosis, diabetes, or spinal cord injury.

For many other conditions, including anxiety and pain associated with cancer, rheumatic diseases, and fibromyalgia, there was no conclusive evidence to confirm the effectiveness of prescribed medicinal cannabis.

Regarding the safety of prescribed medicinal cannabis, the review found that serious adverse events appear to be uncommon.

However, there is evidence of some side-effects such as dizziness, dry mouth, sedation, and headache. There was mixed evidence regarding the likelihood of other adverse events such as drowsiness, nausea, and psychiatric disorder adverse events. The HRB findings align with those reported in other reviews.

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Methodology

The HRB (Health Research Board) review was an overview of reviews. While traditional systematic reviews compile evidence from original research studies (primary studies), an overview of reviews aggregates evidence from existing systematic reviews.

This review focused on systematic reviews involving adults who received prescribed medicinal cannabis containing natural or synthetic cannabidiol (CBD), tetrahydrocannabinol (THC), or their derivatives. It excluded evidence related to recreational cannabis use or medicinal cannabis use without prescription or medical supervision.

The 47 included reviews covered research from the past 30+ years on a variety of medical conditions, including cancer, multiple sclerosis, rheumatic diseases, chronic pain, and mental health and neuropsychological conditions.

Medical cannabis in ireland and what you need to know

Conclusion

The evidence review highlighted a fragmented body of research. The existence of many types of medicinal cannabis makes it challenging to compile robust evidence for a specific formulation for a given condition or complaint.

Further high-quality research based on randomised controlled trials is necessary. Meanwhile, this review will aid in informing future policy decisions on the use of prescribed medicinal cannabis, incorporating input from patient groups, clinicians, and service planners.

The full text of the review is available for download on the HRB website.