Introduction

Multiple Sclerosis, known as MS, is a neurological autoimmune condition which is increasingly affecting many people worldwide. There has been concern in the increase of MS cases throughout the world, in both developed and developing countries.³

The main issue with MS is that the causes of the disease are yet to be fully understood by scientists. It is also a very complex disease, where many risk factors can be involved in its development.²

However, from what is understood, it is a disease which involves inflammation of the central nervous system. This results in a variety of symptoms and neuropathic pain.

Medical cannabis

The symptoms of MS are understood to be very painful, challenging and disruptive to live with. Despite the current treatment options available, some people choose to medicate through the use of medical cannabis.

This article aims to give a comprehensive view on the current treatment available for MS, and how medical cannabis may present as a therapeutic intervention for some people, to manage their MS symptoms.

Pain in MS

When people are diagnosed with MS, they can present with a wide range of symptoms. Though these symptoms may specifically require some drug intervention, for many people, these therapeutics are limited in controlling and managing their symptoms and therefore their pain.

Types of pain

People with MS can suffer with one or many of these symptoms which leads to chronic pain. This pain negatively affects quality of life for many people with MS.

• Optical Neuritis: Optic neuritis is when the optical nerve becomes inflamed. This can cause damage which can then disrupt the normal function of the optic nerve like vision and colour perception
• Uhthoff's phenomenon: When the body temperature of a person with MS rises, sometimes their usual symptoms can also worsen, this is known as uhthoff's phenomenon
• Lhermitte's phenomenon: This is experienced by some people with MS. It can feel like a electrical shock that travels down through the spine or the limbs

Muscle spasticity is also associated with MS and is often one of the more uncomfortable and painful symptoms. It can affect 60%-80% of people with MS.³

MS relapse 

MS relapses can occur and develop over a number of hours to days. Most often a plateau will be reached after a few weeks and then a person will begin to recover from the relapse.

Due to the duration and symptoms, it is not only be extremely uncomfortable and painful for the person, but also tends to cause permanent damage each time a relapse occurs.

For example, in the case of a person having already existing optic neuritis, it will get increasingly worse throughout the relapse. As a person begins to recover and gain proper sight again, following the relapse, there may be abnormalities which remain from the flare-up. These can be things like loss of colour vision or lack of depth perception.²

The current conventional treatments and management of MS

The several types of ways in which MS is treated and managed is usually divided into disease-modifying therapies and symptomatic treatment. 

Disease-modifying treatments (DMTs)

Disease-modifying therapies are important in early treatment of MS. In this instant, a type of drug can directly affect how a person's body deals with the disease. They can be important for long term effects and prevention of any further deterioration and disability.

These types of therapies are therefore usually the closest to a potential cure to MS. So whilst cannabis has shown effectiveness in treating pain, it's most likely not an alternative to these DMT, but instead an addition to be used in combination.

Symptomatic treatment 

These types of drugs are therefore not specific to MS and are primarily looking at alleviating neuropathic pain and cognitive impairment. Sativex is an example of a common symptomatic cannabis drug used for people who have MS.²

How cannabis can be used for pain relief in people with MS

The use of cannabis could be classified as a type of symptomatic treatment. Though progress has been made with treatments like DMTs, people with MS have continued with their symptoms and pain. Despite the opioids used, they sometimes are simply just not enough to make people with MS comfortable.

Medical cannabis can be introduced here as an alternative or additional therapy to help alleviate the issues that traditional drugs cannot.

Many other studies have introduced medical cannabis for treating a vast variety of medical conditions. In this case however, particular studies have shown the benefits of cannabis use. Patients have reported extensive pain relief as a result of its use.

From the many cannabinoids in cannabis, THC and CBD are some of the primary ones used in cannabinoid based drugs. Though they both differ in their effects.

There are various routes of administration

• Smoking (inhalation)
• Tablets 
• Edibles (Foods containing cannabis extract)
• Oral oils
• Vaporizers

For therapeutic use, oral administration is the most favoured, due to stability and ability to give a known dosage and concentration.

Sativex (Nabiximols)

Sativex is an example of a cannabinoid drug which is administered orally through an oral mucosal spray. 

Sativex is a current cannabis based drug used to treat MS. It is approved within Europe and in the UK. In the UK it is the only drug to treat the specific muscle stiffness and spasms resulting from MS.

It includes two cannabinoids, THC and CBD.⁷ Nabiximols can effectively alleviate MS associated pain as well as sleep disruption caused by this pain.

Dronabinol

Dronabinol is synthetic version of the THC cannabinoid It has been looked at as a possible treatment. Severe adverse side effects are usually rare with this type of drug, making it a suitable treatment for long term therapy.

Clinical trials have shown the drug as well tolerated and safe, particularly for those who may have issues of drug abuse.⁷

The benefits of medical cannabis use in MS

The main thing is that cannabis use can reduce inflammation, which is one of the predominant causes of MS.It has also shown promising results from reducing spasticity in patients who suffer from this symptom.

In one study, medical cannabis showed to have improved pain in 72% of patients who took the medical cannabis. Muscle spasticity was improved in 48% of patients and 40% of patients reported that sleep had also improved.⁴

MS related pain can often lead to sleep disturbances. The reduction of pain can have a positive impact on sleep and therefore improve quality of life for many of those with MS.^7,1

Risks and side effects

With any type of therapy and medication, it's important to understand that there can be both risk and side effects associated with them. The use of cannabis, whilst being advantageous can also come with some unpleasant side effects. It is therefore important to be aware of the possibility of these occurring.

Short term

Studies have shown that in some patients, there can be adverse affects which come along with use of oral cannabis. These include dry mouth, dizziness, weakness and fatigue. Despite this, the study also showed that these effects were mild to moderate in the vast majority of patients who did experience them.⁴

In particular, fatigue can be one of the more common and unpleasant adverse effects.For those with mild symptoms, they are well worth some discomfort for the reward of satisfactory pain relief.

The drug sativex particularly describes possible effects of dizziness, blurred vision, vertigo and constipation. The development of depression has also been noted as a more severe side effect.

Smoking cannabis

Though this is a very popular way of administration, inhalation is also accompanied by impairment and adverse affects which are usually associated with smoking. 

This can be a problematic administrative way of taking cannabis, and is not always recommended as the best way of administration when treating MS.⁶

Long term

The current studies on the long term effect of medical cannabis in patients with MS is still quite limited. This therefore means that there isn't much information on how medical cannabis will affect a person after long term use.

Effects can change and though medical cannabis is well tolerated in short-term studies, there is not enough evidence to be sure of the efficacy of it when used long term. This should be considered when deciding to manage MS symptoms though cannabis use.⁵

Considerations when choosing to medicate with cannabis 

The use of medical cannabis should be guided and regulated by a healthcare professional. Often individualised therapy is required when using medical cannabis, to ensure the safety and efficiency of the treatment in treating a patient.

Legality 

Though medical cannabis has shown some extensive results, it may not necessarily be legal in many countries. The legality of the treatment therefore is extremely important to consider.

In the UK for example, cannabis is not legal for recreational use. Although administered via the NHS, medical cannabis is not commonly prescribed. However, a small number of people with multiple sclerosis whose treatments have not helped are sometimes eligible for a prescription for medical cannabis ⁽⁵⁾.

Summary

The use of medical cannabis to treat symptoms of MS has shown some promising results and potential as an effective method of addressing chronic pain and spasticity.

CBD and THC cannabinoids have shown to be especially beneficial in pain reduction and muscle relaxation. Overall the effects of medical cannabis have shown a positive impact on MS symptoms in those who take it.

Though these effects are significant, it is important to be aware of possible risks and side effects as a result of cannabis use. These should be especially considered when wheying risk over reward. Lack of trials exploring long term effects of cannabis is also important to consider when deciding whether medical cannabis is the right treatment for you.