Spasticity after a spinal cord injury is the leg that kicks out during a transfer, the trunk that locks when you sit up, the clonus that rattles a foot off the footplate. In a national Danish survey of 537 people with traumatic spinal cord injury, 71% reported it. The honest answer to the cannabis question starts with a headcount.
Two small randomized trials were built around spinal cord injury spasticity, and between them they randomized 25 people. The largest oral capsule trial to include the injury, a 2023 Danish study, enrolled 15 people with spinal cord injury among 134 and found THC no better than placebo. The rest of the quoted evidence comes from multiple sclerosis, where the nabiximols trials and the NHS four-week stop rule live on our MS spasticity page. Our position: a THC edible for spinal cord injury spasticity is a borrowed-evidence add-on, defensible only after the standard treatments and only with the physiatrist in the loop. The injury adds two hazards the MS trials barely had to weigh. Blood pressure that already falls when you sit up, and transfers that lean on the very stiffness the THC is meant to loosen.
Do cannabinoids help spinal cord injury spasticity?
The direct evidence is two small trials pointing the same rough direction with almost no statistical weight behind them, and one bigger capsule trial that found nothing. A 2021 systematic review of 34 studies found only eight that tested cannabinoids as treatment, and called the size and clinical significance of the effect unclear.
The cleaner trial is Pooyania 2010, out of the University of Manitoba. Twelve people with spinal cord injury and spasticity took nabilone, a synthetic THC analogue sold as a capsule, at 0.5 mg once a day with the option of twice a day, or placebo for four weeks, then crossed over after a two-week washout. Eleven finished, all men, mean age 42, six with tetraplegia and five with paraplegia. Their usual spasticity drugs stayed unchanged. On the primary outcome, the Ashworth score in the most affected muscle group, nabilone won by a mean 0.9 points (P=.003), and the total Ashworth score moved too. On the patients' own visual analogue scale and spasm frequency score there was no significant difference.
In the MS trials the drug kept failing the neurologist's ruler and passing the patient's diary. In this crossover the ruler moved and the patients did not report feeling it. Eleven men is too few to make anything of it. The 2021 review rated the Pooyania trial poor quality.
How much THC did the spinal cord injury trials use?
More than a gummy-aisle dose. The Swiss study by Hagenbach and colleagues started oral THC at a single 10 mg dose, and mean daily doses reached 31 mg, which our dosing guide classes as very high (30mg and above). The authors concluded that at least 15 to 20 mg a day was needed for a therapeutic effect.
Hagenbach 2007 ran three six-week phases at REHAB Basel with 25 people. Twenty-two took oral THC open label and 15 completed that phase; eight took a rectal THC preparation; and only in the third phase were six people randomized to THC and seven to placebo. Participants had stopped all their antispasticity drugs before enrolling, so the trial tested THC alone in people off baclofen, a situation almost nobody reading this is in. The Ashworth sum score fell from 16.7 at baseline to 8.9 by day 43 on oral THC. The main reasons people dropped out were increased pain and psychological side effects, in a population where 73% already live with chronic pain.
The trial closest to an edible is the Danish one, by Hansen and colleagues, published in 2023. It gave swallowed capsules of THC, CBD, both, or placebo, titrated over three weeks to a ceiling of 22.5 mg THC and 45 mg CBD a day, for six weeks. It planned 448 people and randomized 134 after COVID-19 and recruitment trouble, 119 with MS and 15 with spinal cord injury. No arm beat placebo on spasticity or on neuropathic pain. Two of the three drug-related hospitalizations were in the THC group, one of them for dizziness and a fall. A capsule titrated to 22.5 mg is as close as research gets to a gummy routine, and it came back empty.
Why does blood pressure make THC riskier after a spinal cord injury?
Because the injury has already taken some of the body's blood pressure control. Sympathetic control of the heart and the blood vessels of the gut and legs runs through the thoracic and upper lumbar cord, and many people with lesions above T6 have orthostatic hypotension, often without the warning symptoms that would make them report it.
That is the 2018 Wecht and Bauman review from the Bronx VA, and the symptoms it lists are dizziness, lightheadedness, nausea, blurred vision, ringing in the ears, headache and fainting. Now stack the drugs. The FDA label for dronabinol, which is prescription THC, says subjects have experienced orthostatic hypotension or syncope upon abrupt standing. The tizanidine label warns of hypotension, reports syncope after marketing, and flags people moving from lying down to a fixed upright position as at higher risk. Someone with a T4 injury on tizanidine who adds THC is layering two labelled blood pressure effects on a nervous system that already handles sitting up badly.
Timing makes it worse. On our edible timing guide, onset runs 30 minutes to 2 hours after eating and the main effects last 4 to 8 hours. A gummy taken in the evening is still working through the night transfer to the commode and, at higher doses, into the morning one. A near-faint on sitting up after THC goes to the spinal cord injury team the same day.
Can you take an edible with baclofen or tizanidine?
Only with the prescriber knowing, and with the baclofen dose left alone. The baclofen and tizanidine labels both say their sedating effects add to alcohol and other CNS depressants, and THC is one. The baclofen label adds a caution that matters more here than in MS: care is needed where spasticity is used to hold upright posture and balance.
Plenty of people with incomplete injuries stand, pivot or transfer partly on their tone. Loosen it with a muscle relaxant plus THC, add the sedation of both, and the pivot that worked yesterday is a fall today. What the Sativex product information says about baclofen is on the MS spasticity page.
The rule that cannot bend is about stopping. The oral baclofen label reports hallucinations and seizures on abrupt withdrawal and says the dose should be reduced slowly. The intrathecal label carries a boxed warning: abrupt discontinuation, whatever the cause, has led to high fever, altered mental state, rebound spasticity and muscle rigidity, and in rare cases rhabdomyolysis, multiple organ failure and death. It names spinal cord injuries at T6 or above among the patients at apparent risk, and says abrupt withdrawal can trigger an autonomic dysreflexic episode. A gummy that seems to help is never a reason to skip a pump refill or taper baclofen without the physiatrist.
When does worse spasticity mean something other than a dosing problem?
When it changes. The Norwegian review lists an over-filled bladder, constipation, acute infection, syringomyelia and bone fractures as factors that can substantially change the degree of spasticity, and says they must be looked for before treatment changes. A flare is information about the bladder, the bowel or the skin before it is a reason for more THC.
A bowel routine and an intermittent catheterisation schedule run on a clock, and the Danish survey's users named inertia and feeling quiet or subdued as the main negative effects. Constipation turned up among the commonest side effects in the dronabinol pain trial, in both arms. None of that rules THC out. It does mean the spasticity diary and the bowel and bladder log belong on the same page, and that the physiatrist sees both.
Is spinal cord injury nerve pain a separate question?
Yes, with its own evidence and its own guideline. In the Danish survey 73% reported chronic pain, and 60% of those used words suggesting neuropathic pain. The 2016 Canadian CanPain SCI guideline found insufficient evidence to recommend cannabinoids for it and put pregabalin first, then gabapentin, then amitriptyline, all three first-line.
The THC trials split. Rintala 2010, at the Houston VA, compared oral dronabinol with diphenhydramine as an active control: seven enrolled, two withdrew on dronabinol, and in the five who finished dronabinol did no better than the antihistamine. Wilsey 2016 put 42 people with spinal cord injury or disease through 8-hour lab sessions of vaporized cannabis at 2.9% and 6.7% THC or placebo and found real pain reduction, with the two strengths no different from each other, so the authors favoured the lower one. The newest result is CBD alone: a Sydney crossover published in June 2026 titrated 40 people to 800 mg of oral CBD a day for six weeks and found pain about half a point lower on a ten-point scale than on placebo, which the authors called modest. At 25 mg a piece, that is 32 CBD gummies a day. The guideline lists cannabinoids as a top research priority, the polite way of saying nobody knows yet. The wider evidence is on our neuropathic pain page.
Why do so many people with spinal cord injury use cannabis anyway?
Partly for the spasticity, partly because they already did. In the Danish survey 36% had tried cannabis and 9% were current users; 65% of current users took it partly for injury consequences and 59% reported at least a good effect on pain and spasticity. In a Colorado survey, 70% of users with spinal cord injury cited spasticity.
The detail that reframes the Danish numbers: 79% of current users had started before their injury. Pleasure was the main stated reason, and the authors described considerable overlap between recreational and disability-related use. So the most-used cannabis medicine in spinal cord injury is a joint that predates the wheelchair, which tells you a great deal about habit and very little about gummies.