Table 1

Some of the more commonly used oral medicines

Muscle relaxantBackground and effectSide effectDose
BaclofenThe commonest drug for adult and childhood hypertonia, used since the 1970sIt has difficulty crossing the blood–brain barrier and therefore high-peripheral doses of oral medicine are necessary for effectStart
5 mg, three times a day, halved in very small children
It works on the pre and postsynaptic GABAB receptors of the spine to reduce excitation of the spinal reflex arcAs such, it has a narrow therapeutic window before significant side effects of truncal hypotonia, sedation and increased seizure propensity are seenMax
0.3 mg/kg/day. Increased slowly to effect or side effect with upper limits up to 5 mg/kg/day
TizanidineUsed increasingly frequently in the adult populationThere is limited experience of its use in childrenUncertain start
1 mg twice daily <10 years
2 mg od >10 years
This central α2-noradrenergic agonist is generally better tolerated than baclofen in adultsSedation, hypotension, agitation, depression and gastrointestinal problems are the main side effectsMax
0.05 mg/kg/day
2 mg three times a day >12 years
DiazepamOther benzodiazepines work at the spinal GABA level by increasing presynaptic inhibition. They are extremely effective, especially in short-term use if emergency muscle relaxation is needed or sleep disturbedHighly sedating and tolerance is easily developedStart
0.25 mg/kg twice daily
Benzodiazepine withdrawal syndrome is a significant concern with long-term use, especially in the very youngMax
Infant 2.5 mg twice daily
Child 5 mg twice daily
>12 years 10 mg twice daily
DantroleneWorks at the muscle level by inhibiting calcium release from the sarcoplasmic reticulumIt causes global weakness and rarely, though catastrophically, liver failure in around 1% of patientsStart
0.5 mg/kg twice daily for 4 days, increase to three times a day then four times a day
Max
3 mg/kg four times a day or 100 mg four times a day
Antidystonic medicine
Initiation and supervision of such treatment should be in specialist units
LaevoDopa plus CocareldopaIf there is any possible doubt about diagnosis from history and/or neuroimaging then a trial of LaevoDopa should be given. Rarely a DOPA responsive dystonia can mimic CP with extraordinary benefits for the individual if treated earlyIt is given with a peripheral inhibitor – Co Careldopa (Sinemet, Madopar) to minimise side effects of nausea, insomnia and increased choreaStart
1–2 mg/kg/day LDopa in —four – six doses
Laevo:Cocarel – 4:1 ration at low dose, 10:1 ratio at high doseMax
Increase every 2–3 days to max 10 mg/kg/day
Check liver function 6 monthly
TrihexyphenidylProbably the antidystonic medicine with the greatest therapeutic benefitSide effects come from its mode of action and include disorientation, gastrointestinal disturbances (especially constipation), urinary retention and xerostomia (excessively dry mouth)Start
0.5, 1 or 2 mg twice daily, increase weekly to twice daily, then three times a day, then 0.5 mg – 2 mg/week
This anticholinergic agent works at the level of the basal gangliaMax
1 mg/kg/day Exceptionally high doses are often necessary, up to 1.6 mg/kg/day
TetrabenazineDopamine depletors, prevent neurotransmitter degradationAkathesia, depression and other mood disorders, agitationStart
12.5 mg increase slowly to max
Max
100 mg/day
  • CP, cerebral palsy; DOPA, dihydroxyphenylalanine; GABA, γ-amino butyric acid.