Medical cannabis in palliative care

What is medical cannabis?

Medical cannabis refers to medicines derived from the cannabis plant. In the UK, cannabis based medicinal products (CBMPs) can be prescribed by specialist doctors to help manage symptoms associated with certain medical conditions.

They contain substances called cannabinoids. The two cannabinoids most used in medical treatments are:

• Cannabidiol (CBD)  -  which does not cause a "high" and may help with symptoms such as anxiety, sleep difficulties, and pain.

• Tetrahydrocannabinol (THC)  -  which can affect mood and perception and may help with pain, nausea, appetite loss, and sleep disturbance.

Medical cannabis is not a cure for serious illness, but some people find it helps manage symptoms and improves their quality of life.

People receiving palliative care often experience symptoms such as pain, nausea, loss of appetite, anxiety, poor sleep, and fatigue. While conventional medicines are effective for many people, some symptoms can remain difficult to control.

Medical cannabis may sometimes be considered as an additional treatment option when standard approaches have not provided sufficient relief or have caused troublesome side effects.

Cannabis-based medicines are available in several forms, including oils, capsules, pastilles, vaporised flower, vape cartridges, suppositories, pessaries, and oral sprays. Your specialist will discuss which option may be most suitable for you.

How does it work?

The body naturally produces chemicals called endocannabinoids that interact with receptors throughout the brain, nervous system, and immune system.

This natural network is called the endocannabinoid system. This system helps regulate a wide range of functions, including:

• Pain perception.

• Mood.

• Sleep.

• Appetite.

• Memory.

• Immune responses.

Cannabinoids found in medical cannabis act on the same system. Researchers have therefore investigated whether medical cannabis might help relieve some of the symptoms experienced by people with advanced illness. They are still working to understand exactly how these effects occur and why some people respond better than others.

What is it used for in palliative care?

Medical cannabis may be prescribed to help manage symptoms associated with advanced illness.

Pain

Pain is one of the most common symptoms experienced by people receiving palliative care. Some studies suggest that medical cannabis may help certain patients, particularly when conventional treatments have not provided adequate relief.

It may be particularly helpful for certain types of nerve-related (neuropathic) pain.

Nausea and vomiting

Cannabinoid medicines have been used for many years to help control nausea and vomiting, particularly when associated with cancer treatment.

There is reasonably good evidence that some types of medical cannabis can be effective when standard anti-sickness medications have not worked effectively.

Loss of appetite and weight loss

Some medical cannabis products - particularly those containing THC - may help stimulate appetite in some people.

Sleep problems

Many patients using medical cannabis report improvements in their ability to fall asleep and stay asleep. Better sleep may in turn improve coping, energy levels, and quality of life.

Research in this area is encouraging but remains limited.

Anxiety and emotional distress

Some people find that medical cannabis help reduce anxiety and improve relaxation. However, THC containing medicines can occasionally worsen anxiety in some individuals, so careful prescribing and monitoring are important.

Generally medicines containing higher levels of CBD and lower levels of THC - if any - are prescribed for this purpose.

Muscle spasms

Certain cannabis-based medicines may help reduce muscle stiffness and spasms in some neurological conditions.

Not everyone experiences benefit, and medical cannabis is usually considered as part of a wider treatment plan rather than as a standalone treatment.

Improving quality of life

In palliative care, success is not always measured by symptom scores alone. For many people, the most important goal is maintaining independence, comfort, and the ability to participate in activities that matter to them.

Some patients using medical cannabis report improvements in overall quality of life, even when changes in individual symptoms such as pain are modest.

Better sleep, reduced anxiety, improved appetite, greater enjoyment of daily activities, and spending more meaningful time with family and friends can all contribute to a sense of wellbeing.

Medical cannabis is therefore often assessed not only by whether it reduces a particular symptom, but by whether it helps a person live as well as possible despite their illness.

Overall, current evidence suggests that medical cannabis may help some individuals, but it is not a cure and does not work for everyone.

Side effects of medical cannabis

Like all medicines, medical cannabis can cause side effects. Many side effects are mild and improve as the body adjusts to treatment.

Common side effects include:

• Dry mouth.

• Drowsiness.

• Dizziness.

• Tiredness.

• Increased appetite.

• Mild difficulty concentrating.

• Feeling light-headed.

Less common side effects include:

• Anxiety.

• Restlessness.

• Low blood pressure.

• Heart palpitations.

• Mood changes.

Higher doses of THC-containing products may occasionally cause:

• Confusion.

• Paranoia.

• Hallucinations.

• Impaired judgement.

• Impaired coordination.

Long-term, frequent cannabis use can lead to cannabinoid hyperemesis syndrome (CHS), which can cause episodes of severe nausea, repeated vomiting, and retching, sometimes referred to as “scromiting”.

Most side effects improve when the dose is reduced or treatment is stopped. You should contact your healthcare professional if you experience severe or persistent side effects.

How to manage side effects

Many side effects can be reduced by starting with a low dose and increasing gradually under medical supervision.

• Dry mouth

  • Sip water regularly.

  • Chew sugar-free gum.

  • Consider saliva replacement products if symptoms are troublesome.

• Drowsiness

  • Avoid driving or operating machinery if you feel sleepy.

  • Consider taking part or all of the dose in the evening if advised by your clinician.

• Dizziness

  • Stand up slowly from sitting or lying positions.

  • Ensure you are drinking enough fluids.

• Anxiety or feeling unsettled

  • Speak to your clinician.

  • A dose adjustment or change in formulation may help.

  • Products containing more CBD and less THC may be better tolerated by some people.

Types of medical cannabis in palliative care

Oils

Cannabis oils are among the most prescribed forms of medical cannabis. They are usually placed under the tongue using a dropper or swallowed.

Advantages

• Easy to adjust the dose.

• Discreet and simple to use.

• No inhalation required.

• Effects can last for several hours.

• Suitable for regular symptom control.

Disadvantages

• May take between 30 minutes and 2 hours to work.

• Dose adjustments can take time to assess.

• Some people dislike the taste.

• Effects may be influenced by food intake and digestion.

Pastilles

Pastilles are small edible formulations that are chewable, containing a measured amount of THC, CBD, or a combination of both.

They are suitable for patients needing longer-lasting relief but wishing to avoid oils.

Advantages

• Easy and convenient to use.

• Precise dosing.

• Portable and discreet.

• Useful for people who dislike oils.

Disadvantages

• Can take one to three hours to reach full effect.

• Effects may last longer than expected - usually 4 to 8 hours but can last up to 12 hours

• May not be suitable for people with swallowing difficulties.

Capsules

Capsules contain a measured dose of cannabinoids and are swallowed like many other medicines.

Advantages

• Familiar and convenient to use.

• Precise and consistent dosing.

• Tasteless.

• Easy to transport and store.

Disadvantages

• Slower onset of action than inhaled products, similarly to pastilles 

• Less flexibility when adjusting the dose.

• May not be suitable for people who have difficulty swallowing.

Vaporised Flower

Dried cannabis flower is heated in a medical vaporiser, allowing cannabinoids to be inhaled without burning the plant material.

Advantages

• Rapid onset of action, often within 2 to 5 minutes.

• Peak level within 3 to 10 minutes

• Useful for symptoms that occur suddenly.

• Allows patients to assess effects quickly.

• Flexible dosing.

Disadvantages

• Effects tend to wear off more quickly than oral preparations. Duration of action 1 to 3 hours

• Requires a vaporiser device.

• Some people experience throat irritation or coughing.

• The smell may be noticeable to others.

Vape Cartridges

Vape cartridges contain cannabis extracts that are heated using a compatible battery-powered device.

Advantages

• Rapid onset of action, often within 2 to 5 minutes.

• They reach peak level within 3 to 10 minutes

• Convenient and portable.

• Consistent dosing.

• No preparation required.

Disadvantages

• Effects wear off more quickly than oils or capsules. Usual duration of action is 1 to 3 hours

• Requires a compatible device and charging.

• Some people experience throat irritation.

• Long-term safety data are more limited than for oral products.

Suppositories

Suppositories are inserted into the rectum and allow cannabinoids to be absorbed through the lining of the lower bowel.

Advantages

• Useful when swallowing is difficult.

• Can be used when nausea or vomiting limits oral medications.

• May provide prolonged symptom control.

• May be helpful when gastrointestinal absorption is impaired.

Disadvantages

• Some people find this route uncomfortable or inconvenient.

• Absorption can vary between individuals.

• Availability may be limited.

Pessaries

Pessaries are inserted into the vagina and may provide local or systemic absorption of cannabinoids.

Advantages

• May be useful for pelvic or gynaecological symptoms.

• Avoids swallowing medication.

• May reduce some systemic side effects.

• Can be used when oral medications are difficult to tolerate.

Disadvantages

• Limited research compared with other formulations.

• Not suitable for everyone.

Typical onset and duration by cannabis formulation

Always take medical cannabis exactly as prescribed. If you miss a dose, follow the advice provided by your healthcare professional or pharmacist.

How to store medical cannabis

Keep medical cannabis:

• In its original packaging.

• Out of sight and reach of children.

• In a cool, dry place, unless otherwise instructed.

• Away from direct sunlight and excessive heat.

Because medical cannabis is a prescribed medicine, it should never be shared with anyone else, even if they have similar symptoms.

Return any unwanted or expired medication to a pharmacy for safe disposal.

Frequently asked questions

Is medical cannabis legal in the UK?

Yes. Since 2018, specialist doctors have been able to prescribe cannabis-based medicinal products in certain circumstances. Recreational cannabis remains illegal.

Will medical cannabis make me feel high?

Some products containing THC may cause feelings of relaxation, altered perception, or mild intoxication. CBD-only products do not produce a high.

Can I drive while taking medical cannabis?

Patients prescribed medical cannabis may be able to drive legally, but not if they feel impaired. This means if they are feeling sleepy or dizzy, confused or slow to react, light headed, unusually anxious or disorientated, unable to concentrate, have blurred or double vision, feel unsteady or poorly co-ordinated, feel “high”.

Always discuss driving with your clinician and follow their advice carefully.

Is medical cannabis addictive?

The risk is generally lower than many people assume when products are used under medical supervision. However, dependence can occur, particularly with higher-THC products used over long periods.

Can medical cannabis cure cancer or other serious illnesses?

No. There is currently no reliable evidence that medical cannabis cures cancer or most other serious illnesses. In palliative care, its role is to help manage symptoms and improve quality of life.

Will it work for everyone?

No. Some people experience significant improvements, while others notice little or no benefit. Responses vary between individuals.