With more states approving the use of medical marijuana, we examine current therapies for spasticity caused by MS and compare them to Sativex, a cannabis derivative in phase III trials that’s been fast-tracked by the FDA.

Oregon, Alaska, and Washington, D.C., voted in favor of legalizing marijuana last Tuesday, bringing the number of states that have decriminalized the drug or made special provisions for medicinal use to 23 (plus the District of Columbia). For people who suffer from conditions like cancer, Parkinson’s disease, seizures, or multiple sclerosis (MS) this news could bring relief. Medical marijuana is another tool in a doctor’s arsenal to help these patients fight their personal battles.

Research on the use of marijuana to treat symptoms of MS has been limited, but some studies in the past decade have shown that marijuana relieves MS spasticity.

Read More: Should MS Drugs Cost $62,000 a Year? »

According to the National MS Society, spasticity refers to muscle spasms and feelings of stiffness. It is a common symptom in people who have MS.

When MS damages the nerves that control muscles, it can result in spasticity that impairs movement and causes pain and stiffness. It usually occurs in the legs and can draw them up toward the body with painful cramping or cause spasms in the lower back.

For some patients who have muscle weakness, spasticity can be beneficial to a degree, as it provides them with the stiffness needed to walk. But when it gets out of control and the pain becomes too much to bear, it may be time to consider medication.

Get the Facts: What Is Spasticity? »

Dr. Vijayshree Yadav has studied the use of alternative medicine in MS for many years. In 2011, she wrote, “In a review of six controlled studies evaluating a combination of THC and CBD [the active ingredients in cannabis] for spasticity in MS, it was found that THC–CBD was well tolerated and improved patient self-reports of spasticity.”

Earlier this year, Yadav authored a set of guidelines for the American Academy of Neurology, saying that pill and mouth spray forms of cannabis have shown success in treating spasticity and bladder symptoms in MS patients.

There are just three medications that have been approved by the U.S. Food and Drug Administration (FDA) specifically to relieve MS spasticity: Zanaflex, Baclofen, and Botox. Many other medications are used off-label to treat spasticity, too. The following sections outline how each of them works, how they are taken, and their possible side effects.

Added to this lineup is an oral spray called Sativex, which contains a derivative of medical marijuana. It is made by GW Pharmaceuticals and is available by prescription in 15 countries to treat MS spasticity. In April of this year, the FDA fast-tracked Sativex in the United States. Currently in phase III trials, it may soon be another FDA-approved choice for people with spasticity to consider.

See the Effects of Marijuana on the Body »

You should speak with your doctor about all the possible risks and benefits before making any treatment decisions. This list does not include less common side effects, symptoms of possible adverse events, or signs of overdose.

Since many of drug side effects are similar in nature to symptoms of MS, if you experience any change or worsening of MS symptoms, consult your doctor.

For those with MS who prefer to avoid taking pharmaceutical drugs, other options are worth looking into. Studies have shown that yoga, water aerobics, and physical therapy can also help reduce the muscle stiffness and pain caused by spasticity.

Learn More: Medical Marijuana May Ease MS Symptoms, but Other Alternative Therapies Don’t »

Phase III trials of Sativex have already been completed in the U.K., and the results are promising. Not only did patients see a reduction in spasticity symptoms, they also saw no long-term effects on their mood or cognition.

Side effects of Sativex include increased appetite, dizziness, fatigue, loss of balance, dry mouth, amnesia, memory impairment, blurred vision, constipation, diarrhea, and nausea.

Sativex Facts

How does it work?THC and CBD act as regulators of neural transmitters to reduce limb stiffness and improve motor function.
How do you take it?Sprayed on the mucosal lining of the mouth. To be used in addition to other spasticity treatments.
How often?Dosing varies by patient. Titrated with a maximum dose between 1 and 15 daily.

This drug appears to cause less muscle weakness than others used to treat spasticity, though it can still cause chest pain or discomfort, nausea or vomiting, fever or chills, unusual tiredness, nervousness, and painful urination.

It is used to treat spasticity caused by other diseases too, including amyotrophic lateral sclerosis (ALS), spastic diplegia back pain, fibromyalgia, or injuries to the spine or central nervous system. It is also sometimes prescribed off-label for migraines, seizures, and as a sleep aid.

Zanaflex Facts

How does it work?It works by slowing action in the brain and nervous system to allow the muscles to relax
How do you take it?Tablet or capsule. Consistently taken either with or without food.
How often?Two or three times per day.

Baclofen is a muscle relaxer used to treat a variety of MS symptoms. It is also being studied for possible use as a treatment for alcoholism.

In very severe cases of muscle spasms, Baclofen can be administered through an implanted pump. Side effects include confusion, dizziness, lightheadedness, nausea, drowsiness, and unusual muscle weakness.

Baclofen Facts

How does it work?Baclofen acts on the spinal cord nerves to decrease number and severity of muscle spasms, relieve pain, and improve muscle movement.
How do you take it?Taken as a tablet by mouth.
How often?Taken three times a day.

Botox was originally developed as a nerve gas before World War II. It was first used to treat MS spasticity in 1990 and is now commonly used in cosmetic procedures to fix facial muscles in place.

Side effects include bruising, bleeding, and pain at injection site, neck or back pain, and weakness in muscles near the injection site.

Botox Facts

How does it work?Causes temporary paralysis of nerves.
How do you take it?Given by injection.
How often?Once every 3-4 months.

This drug is usually reserved for chronic, severe cases of spasticity where Baclofen or Gabapentin have not worked.

People with a history of liver damage or severe heart problems should not take this drug, nor should children younger than 5. It may cause dizziness, drowsiness, weakness, and fatigue.

Dantrium Facts

How does it work?A muscle relaxant, used to treat spasticity or muscle spasms associated with spinal cord injuries, stroke, MS, cerebral palsy, or other conditions.
How do you take it?Taken as a capsule by mouth.
How often?Titrated from once per day to 3-4 times per day.

Valium has been used to treat spasticity since the 1960s, but is no longer the first choice due to the drug’s potential for dependence.

In addition to addiction and dependence, side effects include dizziness, drowsiness, loss of balance, feeling less alert, and interacting with antihistamines, tranquilizers, alcohol, and other sedatives.

Valium Facts

How does it work?Slows the transmission of messages from brain to nerves.
How do you take it?As a pill by mouth.
How often?Dose is titrated. Stopping must be gradual, because it causes dependency.

This medication is commonly used to treat epilepsy patients. It is also used as a mood stabilizer for bipolar disorder.

Studies have shown that it can cause serious birth defects in pregnant women. The drug can also cause nausea, dizziness, weakness, constipation, and liver disorders, and can stop contraception medications from working.

Tegretol Facts

How does it work?An anticonvulsant drug used to block or reduce nerve transmission from the brain to the rest of the body.
How do you take it?Taken as a pill by mouth.
How often?Titrated from once a day to several times daily.

Klonopin is more often used to treat muscle tremors in MS than to treat spasticity. It is a benzodiazepine, so it can also be used as a sedative or a hypnotic.

The drug can cause dizziness, muscle weakness, fatigue, confusion, lightheadedness, and depression. It is not designed for patients with liver disease or certain respiratory conditions.

Klonopin Facts

How does it work?Slows the activity of the central nervous system.
How do you take it?Taken as a capsule by mouth.
How often?Dose is titrated. Stopping treatment must be gradual, because it causes dependency.

Gabapentin was originally designed as an anti-seizure drug. It is used more often to treat neuropathic pain in MS (sensations of burning or pins and needles) than spasticity. It is also sometimes prescribed off-label as an anti-anxiety drug and sleep aid.

Side effects include sleepiness or fatigue, reduced white blood cell count, confusion, depression, anxiety, loss of appetite, headache, tremors, speech problems, vertigo, dry mouth, indigestion, nausea, vomiting, diarrhea, and changes in mood.

Neurontin Facts

How does it work?Blocks neurotransmitters and interrupting signals from the brain.
How do you take it?Taken as a tablet by mouth.
How often?Can be titrated to help minimize side effects.

Phenol is reserved for extreme cases of spasticity in those who cannot control their lower limbs, bowel, or bladder. Its most common use is actually as a precursor to plastic.

Once injected, the drug permanently blocks nerve function.

Phenol Facts

How does it work?Phenol impairs the conduction of nerves and is used in cases of severe spasticity where other options>br< have failed. It destroys nerve conduction permanently.
How do you take it?Injected into the intrathecal space within the spinal column.
How often?Since the effect is permanent, it requires only one injection.

Learn More: Which Are the Safest (and Least Safe) MS Drugs on the Market? »