Short answer
No cannabis product is FDA-approved to treat multiple sclerosis. Dronabinol (Marinol, Syndros) and nabilone (Cesamet) are approved for chemotherapy-induced nausea, not for MS. A 2014 guideline from the American Academy of Neurology found moderate evidence that oral cannabis extract and THC reduce patient-reported spasticity and central pain. Evidence for tremor, bladder function, and walking speed was insufficient.
What the AAN guideline found
The American Academy of Neurology reviewed the trials available in 2014. Results:
- Oral cannabis extract: may reduce spasticity and central pain.
- Smoked cannabis: may reduce spasticity.
- THC capsules: may reduce spasticity and central pain.
- Tremor, bladder dysfunction, walking speed: insufficient evidence.
The guideline has not been replaced in the US. Newer trials test nabiximols, an oromucosal spray with THC and CBD in a 1:1 ratio.
Nabiximols and the FDA
Nabiximols (Sativex) is approved for MS spasticity in the UK, Canada, Germany, Spain, and other countries. The FDA has not approved it. US phase 3 trials returned mixed results and did not meet their primary endpoints.
Forms and routes
- Oromucosal spray: fixed THC to CBD ratio, metered dose.
- Oral capsules: dronabinol, nabilone, or CBD isolate.
- Vaporized flower: fast onset, potency varies by batch.
- Smoked flower: fastest onset, adds lung risk.
- Topical products: no evidence for MS spasticity.
Side effects
Common effects are dizziness, drowsiness, dry mouth, fatigue, and nausea. THC can impair memory and balance. MS affects both. Cannabis interacts with drugs processed by CYP3A4 and CYP2C9, including some muscle relaxants and antidepressants. Dizziness raises fall risk. Do not drive after use.
CBD alone
CBD has no FDA approval for MS. Trials of CBD isolate for MS spasticity are small and short. Most positive MS trials used THC, THC plus CBD, or whole-plant extract.
Legal status in the US
Cannabis is Schedule I under federal law. As of 2024, 38 states and the District of Columbia run medical cannabis programs. Rules differ by state for qualifying conditions, possession limits, and product testing. MS is a qualifying condition in most of those states.
Before you start
Talk to your neurologist. Bring the product label and the lab report. Ask about interactions with baclofen, tizanidine, and antidepressants. Start with a low dose. Keep a log of spasticity, sleep, and pain scores. Stop and call your clinician if you feel faint or confused.