What is Medicinal Cannabis?

Cannabinoid based medicines contain naturally occurring cannabinoids (THC, CBD) and are manufactured for medicinal use in humans. These preparations are regulated as cannabinoid medicinal product, or an ingredient of such a product.

Medical cannabis has many active chemical constituents, two which have been investigated the most in respect of their medicinal value: tetrahydrocannabinol (THC) and cannabidiol (CBD).

THC is the major psychoactive constituent of cannabis and responsible for giving the so called “high” to users. CBD on the other hand, is not psychoactive, and is thought to have an anti-psychoactive effect that moderates the ‘high’ caused by the THC. CBD is also believed to reduce some of the other negative effects of THC, such as anxiety. “Pure CBD” is not a controlled drug for the purposes of the 1971 Misuse of Drugs Act.

Synthetic cannabinoids (dronabinol, nabilone) have been developed as medical cannabinoid- based products. Dronabinol is not available as a licensed medicine in the UK, but nabilone is. The Advisory Council on the Misuse of Drugs (ACMD) is of the view that further research into this complex group of diverse substances is important, given their potency and potential harms.

Click to learn more about THC and CBD.

Who can prescribe a cannabis-based product for medicinal use?


Prescribing cannabinoid based products for medicinal use is restricted to consultants (specialist doctors) listed on the Specialist Register of the General Medical CouncilConsultants should only prescribe within their own specialism, and the decision to prescribe should generally be agreed by the multidisciplinary team.

A GP may make a referral to a consultant once the patient has reached the appropriate point in their treatment pathway. Private Doctors who are on the General Medical Council’s specialist register can prescribe cannabinoid based products.

These products are not first line treatments.

Doctors should always first consider prescribing medicines that are licensed for the specific condition the patient presents with. This is because these products have been extensively tested for quality, safety and efficacy and are subject to the quality assurance arrangements that apply to all licensed medicines when they are manufactured.

If this is not possible then the next option would be an off-label use of a licensed medicine if the doctor is confident that it is appropriate for the specific condition.

Prescribing an unlicensed product or “special” (such as cannabinoid based medicines) should be considered third and only if an individual patient has exceptional clinical needs that cannot be met by a licensed or off-label medicine.

Click on the link to access an article co-authored by our Medical Director about Safety Considerations in Cannabinoid-Based Medicine.