Botulinum Toxin (Botox) for Spasticity After Stroke: What to Expect and How Physiotherapy Fits In

Botox is the best-known brand name for botulinum toxin type A. Other products exist, and their doses are not interchangeable. Rehabilitation doctors use it to ease post-stroke spasticity that is focal, meaning it affects a defined group of muscles such as the finger flexors, the elbow flexors or the calf.

It helps to be clear about the limits. It does not treat the stroke, it does not repair damaged brain cells, and it does not strengthen a weak muscle. It also does not fix a contracture, the fixed shortening that develops when muscles and tendons stay tight for a long time, because the toxin acts on excess nerve activity rather than on structural shortening. And it is not a body-wide muscle relaxant; it works mostly in the muscles that are injected.

Stroke rehabilitation guidelines support its use for troublesome focal spasticity, ideally as one part of a rehabilitation plan rather than as a stand-alone treatment.

Nerves signal muscles through a chemical messenger called acetylcholine. Botulinum toxin blocks the release of that messenger at the nerve ending inside the injected muscle, so the muscle contracts with less force. The result is a temporary loosening of the overactive muscle.

• The effect usually begins several days after the injection, not on the same day.
• It commonly reaches its maximum within two to four weeks.
• It lasts roughly three months on average, with shorter or longer effects in individual patients.
• As it wears off, tightness returns gradually. Injections can be repeated after an interval chosen by the doctor, usually not less than twelve weeks.

The weeks when tightness is lower are a treatment window. They are meant to be used for stretching and exercise, not simply waited out in the hope that movement improves by itself.

The neurologist or rehabilitation physician decides after examining the patient. Benefit is more likely when:

• The tightness is focal or limited to a few defined areas rather than affecting the whole body.
• It causes a clear problem, such as pain, difficulty cleaning the palm or cutting nails, trouble dressing, a foot that turns in and makes walking hard or painful in a shoe, or skin damage from the posture.
• The joint can still be moved passively through a reasonable range, meaning the muscle has not become fixed.
• There is a clear goal shared by the patient, family and team, such as “open the hand enough to keep it clean”.

If tightness is widespread, or affects arm and leg together, the doctor may prefer oral medicines such as baclofen or tizanidine, which work on the whole body and can cause drowsiness or weakness, or discuss other options depending on the case.

Agree a specific goal with the doctor before the injection. The goals that are met most reliably involve passive function, meaning things done for the patient:

• Opening the palm and fingers for hygiene, to prevent odour and skin breakdown.
• Making it easier to put an arm into a sleeve, or a foot into a shoe or brace.
• Reducing pain from constant tightness.
• Improving sitting and lying positions.

Improvement in active function, such as gripping a cup or taking a better step, can happen in some people but varies widely and depends on remaining strength and on the training that goes with the injection. That is why hopes should not rest on the injection alone. For the broader recovery picture see when walking improves after stroke.

The doctor first identifies the muscles responsible for the tight posture by examination, and may use ultrasound, electrical stimulation or muscle-signal (EMG) guidance to place the needle accurately. The calculated dose is injected at several points with fine needles. A session usually takes from a few minutes to around half an hour depending on the number of muscles, and general anaesthesia is not normally needed. A local numbing cream or spray may be used when appropriate.

Tell the doctor beforehand about all medicines the patient takes, especially blood thinners and some antibiotics, and about pregnancy, breastfeeding or any nerve and muscle disease such as myasthenia gravis, because these affect the decision.

These figures are averages. Response varies and the doctor and therapist adjust the plan for each person.

Days 1 to 3

Gentle stretching begins if the doctor agrees, and any bruising or soreness at the injection sites is watched. There is no improvement yet, which is normal, so do not be alarmed if nothing has changed.

Day 4 to the end of week 1

The muscle starts to loosen gradually. It is a good time to record how far the hand opens or the angle of the foot with photographs or measurements, so you can compare later.

Weeks 2 to 4

The effect usually peaks. This is when the intensive programme happens: daily stretching, strengthening the opposing muscles, task practice and trying a splint or brace. This is the most important part of the whole plan.

Weeks 5 to 12

The effect gradually fades. Training continues to hold on to gains, and the goal is reviewed with the doctor to decide on the next session.

Around three months

Tightness returns slowly if the underlying cause has not changed. The doctor compares photos and measurements with the original goal to decide whether repeating the injection is worthwhile.

Botulinum toxin is considered reasonably safe when a trained doctor gives a suitable dose, but it is not free of side effects:

• Pain, bruising or mild redness at the injection site, which is the most common.
• More weakness than intended in the injected muscle or a nearby one, which can temporarily affect movement and fades as the effect wears off.
• Flu-like symptoms or tiredness for a few days.
• Rarely, spread of the toxin beyond the injection site, causing swallowing or breathing difficulty or general weakness. This needs emergency care at once.
• Allergic reactions to ingredients in rare cases.

It is not injected through infected skin, and some medicines and conditions call for special care. The treating doctor makes the final decision.

The injection lowers the strength of the tightness, but the real benefit comes when the patient uses that period to move. A physiotherapist can help in the following ways.

Before the injection

A careful assessment of joint range, level of tightness and daily function, photographs or records of the starting position, and a clear measurable goal shared by patient, family and doctor.

In the weeks after the injection

• Regular, gentle stretching of the injected muscle to improve its length, sometimes with a night splint or brace.
• Strengthening the weaker opposing muscles, such as finger extensors or ankle dorsiflexors, because lowering the pull of the tight muscle lets them work.
• Practising daily tasks: reaching and grasping, standing up, and a better stepping pattern, using ideas from post-stroke foot drop where relevant.
• Teaching the family safe stretching and the schedule for the splint.
• Adding aids such as functional electrical stimulation when suitable and approved by the doctor.

When the effect wears off

Results are reviewed against the original goal, and the doctor decides whether to repeat the injection or change the approach.

Whether or not Botox is used, a tight hand or foot needs daily care to prevent complications:

• Clean the palm and between the fingers every day and dry them well. If the therapist advises it, place a clean dry cloth between the fingers to prevent moisture, odour and skin infection.
• Keep nails trimmed so they do not dig into the palm when the fingers curl.
• Check the skin in the armpit, the elbow crease and the sole of the foot for redness, cracking or sores.
• Move joints slowly and gently, and never force a hand open, because that raises tightness and pain.
• Support the arm on a pillow when sitting or lying in a comfortable position that does not increase the pull.
• Make sure shoes fit and do not press on a foot that turns inwards.

For more on this subject read is spasticity normal after stroke?.

No single option suits everyone. Options include regular stretching, good sitting and sleeping positions, splints and braces, electrical stimulation in some cases, oral medicines when tightness is widespread, and, for severe resistant cases, advanced options doctors may discuss such as a baclofen pump delivering medicine around the spinal cord, or surgery to improve position. Causes and options differ between patients, so this page is not a substitute for medical examination. To understand why tightness develops, see why spasticity occurs after stroke.

• Which muscles will be treated, and what specific goal are we aiming for?
• Is the tightness focal or widespread, and is there a fixed contracture at the joint?
• Which product and dose will be used, and will a guidance device help place the needle?
• When should the effect begin, how long will it last, and when is the next session?
• Which symptoms mean I should call or go to emergency care?
• Is there any conflict with the patient’s current medicines?
• Which exercises and splints should we start straight after the injection?

The weeks after an injection need frequent, organised practice, and repeated trips to clinics are hard for many patients. During a home visit we assess joints, tightness and function, contact the doctor when needed, build a short schedule of stretching, training and splinting, and teach the carer how to carry it out. We do not give injections or change medicines, and we do not promise a guaranteed result; we promise a clear assessment, a written plan and safe training. Call 01097079170 or open the home visit booking page.

• Difficulty swallowing, speaking or breathing in the days or weeks after the injection.
• Sudden general weakness, or weakness spreading to muscles far from the injection site.
• A rash, severe itching, or swelling of the face or lips.
• Severe pain, spreading redness, fever or discharge at an injection site.
• Far more weakness than expected in the hand or foot, which makes daily activity unsafe.
• Any new stroke signs, such as a drooping face, sudden weakness or slurred speech; call an ambulance at once.

This information is educational and does not replace your doctor’s diagnosis or follow-up.