Medicinal cannabis

Specialist hospital doctors can prescribe or recommend cannabis-based products for treatment. The products can be used when the specialist identifies a clinical need for a person and other treatments are not suitable or have not helped.

About medicinal cannabis products

‘Medicinal cannabis’ is a broad term for any sort of cannabis-based product used to relieve symptoms.

Many of these products are available to buy online without a prescription. These products could be illegal and potentially dangerous.

Some products such as hemp oil and capsules are available to buy as food supplements from health stores and other outlets. There is no guarantee these are effective or of good quality.

Prescriptions for a medicinal cannabis product

Medicinal cannabis products are only available on a prescription written by, or recommended by, a specialist hospital doctor.

This is because there is currently limited scientific evidence medicinal cannabis is safe and effective. It is also because there a lack of licensed products available that have undergone the normal strict testing for medicines. This testing means they are safe, of good quality, and are effective.

A hospital specialist might consider prescribing a medicinal cannabis product for you or your child if:

  • your child has one of the rare forms of epilepsy that might be helped by medical cannabis
  • you have spasticity from Multiple Sclerosis (MS) and treatments for this are not helping
  • you have vomiting or feel sick from chemotherapy and anti-sickness treatments aren't helping

The specialist will discuss with you the most suitable treatment option.

If the above does not apply it is unlikely your GP will refer you or your child for medicinal cannabis.

How medicinal cannabis products might help

For adults, there is some evidence that medicinal cannabis products may be able to relieve symptoms including:

  • muscle spasticity caused by MS
  • vomiting and feeling sick after chemotherapy

For children with certain rare forms of epilepsy, trials have shown that medicines containing CBD may help relieve symptoms.

There is some evidence that some medicinal cannabis products can help certain types of pain, though this evidence is not yet strong enough to recommend it for pain relief.

Researchers are currently investigating other possible uses of medicinal cannabis.

Is medicinal cannabis safe

All medicines, including medicinal cannabis products, can cause side effects.

Cannabidiol (CBD) is a chemical substance found in cannabis that has medical benefits.

Tetrahydrocannabinol (THC), is a chemical substance found in cannabis that is linked with psychosis.

The safety of medicinal cannabis products depends on the amount of THC it contains. ‘Pure’ products that only contain CBD, such as Epidiolex, are the safest to use.  But most products will contain a certain amount of THC.

The risks of using cannabis products containing THC are not currently known. That is why clinical trials are needed before they can be licensed for use.

The main risks can include: 

  • psychosis – there is evidence that regular cannabis use increases the risk of developing a psychotic illness such as schizophrenia
  • dependency on the medicine – although scientists believe this risk is probably small when its use is controlled and monitored by a specialist doctor

Generally, the more THC the product contains, the greater these risks. Cannabis bought off the street, where the quality, ingredients and strength are not known, is the most dangerous form to use.

Side effects of medicinal cannabis

After taking medicinal cannabis, it is possible side effects can develop. These include:

If you experience any side effects from medicinal cannabis, report these to your medical team. You can also report them through the Yellow Card Scheme.

CBD can affect how other drugs work. If you are taking a CBD drug along with other medication, always discuss possible interactions with your specialist.

CBD can also affect how your liver works, so doctors would need to monitor you regularly.

Laws on cannabis

Cannabis is a Class-B drug in the UK.

It is illegal to:

  • possess or supply cannabis-based products for medicinal use without a prescription
  • produce or supply cannabis-based products that are not for medicinal use
  • smoke cannabis, or cannabis-based products for medicinal use

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