Introduction

Multiple sclerosis (MS) is an autoimmune condition that gradually damages the protective covering (myelin sheath) and fibres (axons) of nerves in the central nervous system (CNS). Damage to these nerve fibres over time can lead to a variety of symptoms, including neurological decline and muscle stiffness in organs (e.g. organ spasticity), bladder dysfunction and ataxia (poor muscle control), among others.¹

Bladder dysfunction is common among people with MS, and is strongly linked to stress urinary incontinence. The urethral sphincter, also known as the urinary sphincter, helps control the release of urine from the body. When this muscle is not functioning adequately due to MS, it can cause urinary incontinence. In this condition, bladder control is compromised, resulting in urine leaking uncontrollably.² 

Cannabis has been tested and used in some cases to manage MS-related bladder problems, such as urinary tract dysfunction. Initial studies have indicated some potential for cannabinoids and cannabis in treating bladder complications resulting from MS; however, the consensus is that more studies are needed to fully elucidate the effects and complications associated with this form of treatment.³

This article explores how cannabis may help with these issues through the endocannabinoid system (ECS), while also examining its side effects. Different ways of using cannabis and important considerations will also be discussed.

How does MS affect the bladder? 

What is an overactive bladder in MS?

MS can lead to several bladder-related issues that affect urinary function. One of the main issues is an overactive bladder, which causes patients to feel the urge to urinate regardless of how full the bladder is. This is due to the parasympathetic nervous system being affected by MS. As a result, the bladder cannot fill properly, and the voiding reflexes that allow urine to be removed are also compromised, further contributing to an overactive bladder.⁴

People with MS experience more urgency and a greater need to urinate compared to the general population. An overactive bladder also increases the frequency of urination, i.e. how often someone urinates. Urgency and frequency changes are more common than incontinence and can lead to discomfort⁵

Why do people with MS get UTIs or retain urine?

Neurogenic bladder resulting from MS can inhibit the bladder muscle function and cause retention of urine in the bladder.⁶ Urine retention and other bladder issues increase the risk of urinary tract infections (UTI) in people with MS.

Stagnant urine in the bladder can provide an ideal environment for bacteria such as Escherichia coli to grow.⁷ If left untreated, UTIs can lead to kidney damage and conditions such as chronic kidney disease. Therefore, treating and managing UTIs in MS is essential.⁸ 

How do MS bladder problems affect daily life?

These symptoms can cause discomfort and lead to social difficulties, as frequent urination may disrupt daily activities and social situations.⁹ Bladder problems caused by MS can significantly reduce a person’s overall quality of life.

Cannabis and MS bladder

Cannabinoids in cannabis affect bladder function through the endocannabinoid system (ECS). The ECS helps regulate nerve activity by controlling the release of neurotransmitters at the connections between nerve cells.¹⁰ The ECS can also reduce bladder activity, which manages an overactive bladder caused by MS.

There are two receptors within the ECS that Cannabidiol (CBD, a type of cannabinoid) binds to: cannabinoid type-1 and type-2. These are commonly referred to as CB1R and CB2R, respectively. CB2R is especially important in managing bladder issues, as it helps prevent the nerve growth factor from making bladder fibres overly sensitive. As a result, bladder activity decreases, which is very helpful for patients with an overactive bladder.¹¹

Tetrahydrocannabinol (THC) is another common cannabinoid that binds to cannabinoid receptors such as CB1R and CB2R. However, CBD is more commonly linked to changes in ECS function.¹² MS is an autoimmune disease, while the ECS helps limit immune responses and inflammation. Because the ECS helps prevent neurodegeneration, activating this system has been explored as a possible way to treat conditions like MS.¹³

Research on cannabis for MS bladder

There have been research and clinical studies exploring the use of cannabis in treating bladder issues caused by MS. Some studies have indicated that cannabis may reduce the frequency of urination, urgency, and incontinence, with limited side effects; however, more research is needed to justify the same.^{3, 14}

The consensus is that cannabis is both effective and safe in cases of urinary dysfunction and other MS-related bladder problems. Patients have reported improved quality of life and bladder control. Therefore, most current evidence supports the use of cannabis for MS-related bladder complications.¹⁵

Cannabis for MS-related symptoms

There are many different ways to use cannabis. Smoking cannabis is a common method, and trials have shown it can reduce spasticity and pain in MS patients; however, it may also lead to changes in cognitive function and fatigue.¹⁶ Smoking marijuana has also been shown to cause an overactive bladder, so while inhalation may be effective, more research is still needed.¹⁷

Oal forms, such as edibles and certain oils, have been shown to reduce spasticity and pain; therefore, they are the most commonly used for treating MS-related issues. Studies have shown a reduction in urgency and frequency, supporting the effectiveness of oral treatment.

Topical products, such as creams, are also available but are not used as frequently as smoking and oral methods.¹⁸

It is important to balance THC: CBD ratios, as high THC concentrations have been linked to anxiety and psychosis, while CBD helps reduce these effects.¹⁹ In Italy, MS treatments using THC and CBD in a 1:1 ratio are permitted; it is important to keep THC concentration low, as CBD is needed to reduce the psychological effects of cannabis.²⁰

Risks with cannabis use in MS?  

There are some risks associated with using cannabis to treat MS-related bladder issues, such as dry mouth, drowsiness, and fatigue. Although THC reduces inflammation, high doses can have psychoactive effects and may increase pain and anxiety. Hallucinations are also common when THC concentrations are high, and patients may become disoriented as a result.²¹ 

The legality of medical cannabis varies widely between and within countries; for example, it is legal in over 30 states in the United States.²² In the United Kingdom, these products are available through the National Health Service (NHS) for MS treatment; however, access is strictly regulated, and obtaining a prescription can be difficult.²³ However, attitudes towards these treatments have become more positive in recent times, and this trend is likely to continue. 

Cannabis interacts with other drugs; however, many of those interactions are unknown. This is because CBD interacts with receptors beyond CB1R and CB2R. There is currently limited knowledge on drug interactions; therefore, the possible risks must be further researched.²⁴ 

It is integral that treatment plans are tailored to each patient to minimise side effects and interactions with other treatments. Cannabis should only be taken under proper medical supervision and monitoring to avoid potential risks due to the many unknowns surrounding the treatment.

Other treatments and MS bladder problems

Cannabis can be used alongside other medications to treat MS-related bladder issues. Other drugs, such as β3-adrenoreceptor agonists and P2X3 receptor agonists, which target receptors involved in sensing bladder volume, may also be used alongside cannabis.²⁵ There is, however, limited data available on the use of cannabis as part of a combined treatment; therefore, further studies are needed. 

Physical therapies, such as pelvic floor muscle training, can help control and strengthen pelvic muscles. This may prevent incontinence caused by an overactive bladder. Combining cannabis with lifestyle changes and physical therapies like pelvic floor training may benefit MS patients.²⁶

Other lifestyle changes, such as controlling diet, fluid intake, and managing weight, are also known to alleviate overactive bladder symptoms. These modifications should be considered alongside cannabis use.²⁷ These integrative treatments are key to reducing MS-related bladder issues in the future.

Summary

Overall, cannabis can help manage MS-related bladder issues in several ways. Cannabis mainly works through the endocannabinoid system (ECS) to reduce inflammation and help support normal bladder function. Cannabis may be effective at treating an overactive bladder, which in turn prevents urinary tract infections (UTIs) and other complications. 

It is important to manage side effects, such as drowsiness, while using cannabis. High doses of THC, in particular, may cause more harm than good. This can, however, be controlled by monitoring THC and CBD ratios.

There are still many unknowns with cannabis treatment. Although current evidence suggests it can be effective with limited side effects, more research is needed. Further research is needed on the long-term side effects and the overall success of this treatment.

Good communication between patients and healthcare providers is also essential to ensure each treatment plan is tailored to the individual. As knowledge about cannabis increases and more people become aware of its benefits, MS-related bladder issues may become easier in the future.