MS-related spasticity is one of the clearest examples of a defined medical use for a cannabis-based medicine. Nabiximols, marketed in the UK as Sativex, is a standardised THC/CBD mouth spray used in selected adults whose spasticity has not responded adequately to other treatment. Its role is symptom relief. It should not be presented as a cure for multiple sclerosis or a replacement for disease-modifying treatment.
Evidence checked: 1 October 2026. Treatment decisions belong with an MS specialist and the wider clinical team.
What spasticity means in everyday life
Spasticity can involve muscle stiffness, involuntary spasms and difficulty moving or maintaining comfortable positions. Its impact differs between people: sleep may be interrupted, dressing may become difficult, or transfers between bed and chair may be painful. It should be assessed in relation to these effects rather than treated as a single number.
NICE’s MS guidance recommends checking for factors that worsen spasticity, including infections, bladder or bowel problems, pain, pressure sores and poor positioning. Addressing those factors may be important before changing medication.
Reducing muscle tone is not always an uncomplicated improvement. Some people use increased tone to help maintain posture, stand or transfer. Excessive relaxation can make those activities harder. That is why a treatment should be judged against the person’s own functional goals, not simply whether a limb feels less stiff.
What makes Sativex a specific medicine
Sativex contains defined amounts of THC and CBD in an oromucosal spray. It is intended as an addition to existing antispasticity treatment for adults with moderate to severe MS spasticity who have not responded adequately to other medicines and show benefit during an initial trial. Treatment is initiated and supervised by a clinician with relevant specialist expertise. The UK product information sets out its indication, precautions and administration.
This is more precise than saying that cannabis is approved for MS. Approval of one formulation for one symptom does not establish that every cannabis flower, oil or retail CBD product has the same effects. Nor does it demonstrate benefit for every symptom associated with MS, such as fatigue, tremor or cognitive difficulty.
What the clinical trial tells us
A 2011 trial of nabiximols used an “enriched” design. Initially, 572 participants received active treatment. Those meeting an early response threshold could enter the randomised phase; 241 were subsequently allocated to continue nabiximols or receive placebo. The randomised comparison favoured nabiximols for patient-rated spasticity, with several secondary outcomes also showing benefit.
This design helps answer whether continued treatment benefits people who respond initially. It does not tell us that every person starting treatment will respond. The distinction is essential when interpreting favourable results from the later phase: the population had already been selected partly on treatment response.
For a patient, the practical lesson is that an initial trial can be informative. Lack of meaningful early benefit is a reason to reconsider treatment, not a personal failure or proof that a stronger cannabis product must be found.
Why the four-week review matters
NICE NG144 recommends a four-week trial of THC:CBD spray for qualifying adults when other pharmacological treatments have been ineffective, subject to the specified funding arrangement. Continued treatment requires at least a 20% improvement on a patient-reported spasticity scale.
That threshold concerns a particular symptom measure. It does not mean that MS is 20% better, that disability has improved by that amount, or that disease progression has slowed. A symptom score needs to be interpreted alongside daily activities and adverse effects.
For illustration, a person might hope to sleep with fewer painful spasms and transfer more comfortably. If spasms improve but dizziness makes transfers unsafe, the review should capture both. A treatment can meet a numerical threshold and still need adjustment because the overall result is unsatisfactory.
How it fits with other MS care
Physiotherapy, positioning, management of aggravating factors and established antispasticity medicines remain relevant. NICE includes oral baclofen as a first-line option where suitable. The appropriate plan depends on symptoms, other conditions and the patient’s preferences; some people need a specialist spasticity service.
Symptom management and disease modification serve different purposes. Improving sleep or muscle comfort does not demonstrate prevention of relapses or repair of damaged nervous tissue. People should continue discussing disease-modifying treatment and new neurological symptoms with their MS team. Neither a good response nor a poor response to a cannabinoid answers those separate questions.
Adverse effects deserve the same attention as benefit
The product information identifies dizziness, fatigue and effects on alertness among the issues to consider. Combining Sativex with other medicines that reduce muscle tone can increase concern about weakness and falls. Mouth discomfort and psychiatric history also require attention. Its prescribing information includes contraindications concerning certain psychotic illnesses and breastfeeding.
The dose is adjusted individually under clinical supervision. Copying another patient’s number of sprays ignores differences in response, other medicines and treatment goals. Likewise, switching from a licensed spray to flower or oil is not a simple conversion based on the word “cannabis”.
What to bring to a review
A brief record can make a specialist appointment more useful. Include the frequency and timing of troublesome spasms, disrupted nights, help needed with personal care and any changes in balance or thinking. Note infections, constipation or other factors that could explain a deterioration.
- What specific activity or symptom was treatment intended to improve?
- Was there a meaningful change during the agreed trial?
- Has the improvement continued?
- Are weakness, dizziness or other effects offsetting the benefit?
- Does the wider spasticity plan need adjustment?
Family or carers can contribute observations with the patient’s agreement, especially when changes affect transfers or nighttime care. Their observations should complement, rather than replace, the person’s own account of comfort and function.
A realistic expectation
For an appropriate responder, a cannabis-based medicine may make a difficult symptom more manageable. That is a meaningful medical purpose without implying a cure. The strongest case for treatment rests on a defined preparation, a defined target and a review showing that the overall benefit is worth continuing.