Treatment guide

Botulinum Toxin for Spasticity

Botulinum toxin injections can reduce activity in selected overactive muscles for a limited period. The best results begin with a specific goal and a coordinated rehabilitation plan.

Botulinum neurotoxin type A is an established treatment for focal or multifocal spasticity. It works at the connection between a nerve and muscle, reducing release of acetylcholine and temporarily lowering the muscle’s ability to contract. It does not repair the original injury to the brain or spinal cord.

Who may be considered?

Injections are most useful when a defined group of muscles contributes to a meaningful problem. Examples include a clenched hand that is difficult to clean, a bent elbow that complicates dressing, painful shoulder positioning, an inward-turning foot or curled toes that interfere with walking or footwear.

The target may be active function, passive function, pain, positioning or prevention of secondary problems. A person does not need to have useful voluntary movement for a passive goal such as hygiene or comfort to be legitimate.

What happens before injection?

The clinician reviews the neurological diagnosis, medications, previous treatment, allergies, swallowing or breathing problems and the intended outcome. Examination identifies which muscles are overactive and whether weakness, contracture or joint disease also contributes. Injecting a muscle that is not responsible for the pattern can add weakness without solving the problem.

Baseline measures may include range, pain, a tone scale, walking or hand tests, photographs, video or Goal Attainment Scaling. The goal should be recorded before treatment.

How are muscles located?

Clinicians use anatomical examination and may add ultrasound, electrical stimulation or electromyography. Guidance can help distinguish neighboring muscles and avoid nerves or blood vessels, particularly in deep or small targets. Technique depends on the region, available equipment and clinician expertise.

When does it work and how long does it last?

Effects generally begin over several days and build during the following weeks. Benefit is temporary and commonly lasts around three months, although timing varies by product, dose, muscle and individual response. Repeat treatment should follow reassessment, not an automatic schedule alone.

What improvement should be expected?

Evidence strongly supports reduction in focal muscle overactivity. Improvement in comfort, hygiene, limb position and some goal-based outcomes is common when targets are well chosen. Active hand use or walking may improve in selected people, but reduced tone does not restore lost strength, sensation or motor control by itself.

This distinction protects against unrealistic promises. The question is not merely whether a wrist became easier to move in the clinic, but whether the agreed activity or symptom improved.

Rehabilitation after injection

The period of reduced overactivity may make it easier to practice movement, strengthen opposing muscles, adjust a splint, improve positioning or train a task. Physical and occupational therapy should be selected around the goal. The evidence does not establish one identical post-injection program for everyone.

Risks and cautions

Common effects include temporary injection-site discomfort, bruising and weakness in the injected or nearby muscles. Less common but serious risks can include difficulty swallowing, speaking or breathing if toxin effects spread. Product warnings, approved indications and maximum doses vary. People with neuromuscular junction disorders or certain other conditions require particular caution.

Tell the clinician about all medicines and recent botulinum toxin treatment. Seek urgent medical help for breathing or swallowing difficulty, generalized weakness or another severe reaction after injection.

Questions to ask

What exact goal are we treating?
Which muscles are responsible for the pattern?
How will targeting be guided?
What therapy or home program should follow?
When will the outcome be reviewed?
What adverse effects require urgent care?

See the broader spasticity treatment guide and our rehabilitation overview.

Sources

Simpson DM, et al. Botulinum neurotoxin for treatment of spasticity: evidence-based review. Neurology. 2008.
Wissel J, et al. Practical guide to botulinum neurotoxin treatment. Front Neurol. 2022.
Demetrios M, et al. Multidisciplinary rehabilitation following focal treatment. Cochrane Database Syst Rev. 2013.
Francisco GE, et al. Post-Stroke Spasticity. 2021.

Public-service medical disclaimer: this article provides general education. It does not provide diagnosis or treatment and should not guide an individual medical decision.

How a treatment cycle is planned

A botulinum toxin appointment should begin with a defined problem and a realistic goal, not simply a list of tight muscles. Common goal areas in adult spasticity guidelines include pain, involuntary movements, prevention of secondary shortening, easier care of the affected limb, active use and mobility. The clinician then decides whether muscle overactivity is actually limiting that goal and whether weakness, pain, joint restriction or poor motor control also need attention.

Muscle selection and guidance

The dose and muscles selected are individualized. Examination may include observing the task, moving the joints at different speeds and distinguishing dynamic muscle activity from a fixed contracture. Depending on the muscle and clinical setting, the injector may use anatomical landmarks, electrical stimulation, electromyography or ultrasound to improve localization. More toxin is not automatically better: excessive weakening can interfere with transfers, walking, grasp or balance.

Rehabilitation during the response window

The injection changes signaling at the treated neuromuscular junction, but it does not by itself teach a new movement pattern or restore lost skill. Rehabilitation may use the period of reduced overactivity to work on positioning, active movement, strengthening of appropriate muscles, task practice, hygiene, splint review or caregiver techniques. The plan should state who will provide therapy, what will be practiced at home and when progress will be reviewed.

Before the next cycle

Record when the effect began and when it started to wear off.
Note which agreed goal improved and which did not.
Report unwanted weakness, swallowing difficulty, breathing symptoms or other unexpected effects promptly.
Review whether the same muscles and dose remain appropriate.
Bring an updated medication list and relevant changes in health.

Repeat treatment should be based on reassessment rather than an automatic schedule. The Royal College of Physicians describes botulinum toxin as one component of an overall spasticity management program, with outcomes reviewed against the goals set before injection.

Key point: a successful injection cycle is a coordinated process. Goal setting, accurate muscle selection, appropriate dosing, rehabilitation and outcome review are all necessary. If tone decreases but the agreed activity does not improve, that result still provides useful information: weakness, sensory loss, pain, motor-control impairment or fixed shortening may be the more important limitation and may require a different plan.