When using oral medications a good guiding principle is to “start low, go slow” i.e. start with small doses and make changes gradually. This also applies to cutting down or stopping medications. Oral medication may have widespread effects. This can be helpful for some patients with widespread spasticity however for many stroke patients widespread relaxation may be unhelpful. For example, someone being treated with with oral medication for troublesome spasticity in the upper limb may find it harder to mobilise the trunk or lower limb if tone is reduced.
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The main oral anti-spasticity agents used:
Oral anti-spasticity agents
Description
Baclofen
A GABAb selective agonist.
Inhibits transmission at spinal level and also depresses the central nervous system.
It can lower seizure threshold (10% of patients after a stroke will develop seizures) so is generally avoided in those patients with a history of seizures.
A typical starting dose is 5mg anything between once or three times a day.
When changing doses (up or down) changing by 10mg per day per week would be common advice especially for out-patients. One can make changes more quickly in an in-patient setting or where the patient can be monitored more closely.
Max 80-100mg/day in 3 or 4 divided doses.
The main side-effects are sedation and confusion.
N.B. Avoid abrupt withdrawal. Patients should be counselled about this.
Benzodiazepines
Diazepam increases pre-synaptic inhibition of afferent fibres at the spinal cord level via a GABA-mediated mechanism.
It can be very useful for an acute painful spasm.
For many patients clonazepam can be very at night for painful overnight spasms.
The usual starting dose is 250mcg at bedtime, slowly increased to 1mg if helping and if tolerated.
The main side-effects are drowsiness.
Dantrolene
Acts directly on skeletal muscle fibres to block release of calcium from the sarcoplasmic reticulum.
Uncouples muscle contraction from excitation.
Fewer central adverse effects in theory. But in practice often does cause drowsiness.
Can also cause diarrhoea and potentially fatal hepatotoxicity.
The starting dose is 25mg daily. This can be increased after 4-7 days to 25mg TDS.
The usual maintenance dose 75mg three times a day with a maximum dose of 100mg four times a day.
N.B. Need to monitor LFT’s indefinitely.
Tizanidine
Alpha-2 noradrenergic receptor agonist.
Probably reduces spasticity by increasing presynaptic inhibition of motor neurons, reducing facilitation of spinal motor neurons.
Peak effect occurs 1-2 hours after administration and the half life is 2.5 hours. The drug therefore needs to be given a few times throughout the day to be effective.
The starting dose is 2mg once a day.
This can be increase in 2mg increments every 4 days to the usual maintenance dose 16-24 mg in 3-4 divided doses (max 32mg per day).
The main side-effects are drowsiness, dry mouth and hypotension.
N.B. LFT’s monthly for first 4 months,
Gabapentin
If patients have concurrent post-stroke pain, or hypersensitivity to handling, this seems to be especially useful.
The starting dose is 300mg once a day.
This is gradually titrated up in 300mg increments.
The maximum dose is 3.6g daily in 3 divided doses.
It is generally very well-tolerated even at higher doses. Occasionally drowsiness is a problem.
