Muscle spasms and spasticity are involuntary muscle contractions that range from mild tightness to severe, painful, and uncontrollable jerking movements. This condition is not a disease itself but a common symptom of underlying neurological disorders where nerve signals controlling muscle movement are damaged or disrupted. Conditions frequently associated with spasticity include Multiple Sclerosis (MS), spinal cord injury, cerebral palsy, and stroke. Many individuals living with these conditions seek effective relief, leading them to ask if cannabis offers a viable treatment option.
The Biological Mechanism of Action
The potential for cannabis to alleviate muscle spasms is rooted in its interaction with the body’s Endocannabinoid System (ECS), a network that regulates motor function and muscle tone. The ECS features CB1 and CB2 receptors, which are activated by naturally produced cannabinoids. Cannabis introduces plant-derived cannabinoids (phytocannabinoids) that mimic these compounds and interact with the same receptors.
The CB1 receptors are highly concentrated in the central nervous system, controlling movement and muscle excitability. When activated, delta-9-tetrahydrocannabinol (THC) acts on these receptors. This action reduces the release of certain neurotransmitters, dampening the hyper-excitability of nerve pathways responsible for involuntary muscle firing. By modulating this nerve signaling, cannabinoids help reduce the stiffness and involuntary movements characterizing spasticity.
Clinical Evidence and Research Findings
Clinical trials, particularly focusing on Multiple Sclerosis (MS) patients, suggest that cannabis-based products are superior to placebo in reducing patient-reported symptoms of spasticity. For many individuals with treatment-resistant spasticity who found little relief with conventional medications, cannabinoids have led to improvements in muscle stiffness and pain.
While patient-reported outcomes show significant benefit, objective clinical tests sometimes show a less clear-cut difference. A pharmaceutical product called Nabiximols (Sativex), an oromucosal spray containing THC and cannabidiol (CBD), is approved in over 25 countries for treating MS-related spasticity unresponsive to other treatments. Studies demonstrated that Nabiximols improved spasticity scores compared to a placebo, without causing the increase in muscle weakness sometimes associated with other anti-spasticity drugs.
The evidence supporting the use of cannabis-based products for spasticity has led major neurological bodies to acknowledge its potential as a therapeutic agent. The scientific data supports the use of cannabis extracts, particularly those containing THC, as a treatment option for spasticity, especially in cases where first-line therapies have been ineffective.
Comparing Cannabinoids THC versus CBD
The antispasticity effect is predominantly attributed to the interaction of the two main compounds: THC and CBD. Tetrahydrocannabinol (THC) is considered the primary agent for direct muscle spasm relief due to its strong affinity for the CB1 receptors in the central nervous system. Its ability to activate these receptors helps reduce the motor neuron hyper-excitability that causes involuntary contractions.
Cannabidiol (CBD), in contrast, does not directly bind to the CB1 receptor and is less potent for immediate muscle spasm relief when used alone. CBD contributes to the overall therapeutic effect through its anti-inflammatory properties and its ability to modulate the effects of THC. It is believed that CBD can lessen the psychoactive effects of THC while potentially enhancing the muscle-relaxant properties. This synergistic action, often called the entourage effect, suggests that a combination product may offer the most comprehensive relief.
Safety Considerations and Side Effects
The use of cannabis for muscle spasms is associated with various side effects, particularly those related to the psychoactive component, THC. Common acute adverse effects include dizziness, fatigue, dry mouth, and an altered mental status or feeling “high.” The risk of these effects increases with higher doses of THC, which must be carefully managed to balance therapeutic benefit with tolerability.
Long-term use introduces considerations such as the potential for dependency and, for those using inhaled forms, the risk of respiratory issues. Furthermore, THC and CBD can interact with other prescription medications, affecting how they are metabolized by the liver. Due to these potential drawbacks, any decision to use cannabis for spasticity should be made in consultation with a healthcare provider who can monitor for side effects and manage potential drug interactions.