Twenty-three children (aged less than 18 years) and 17 adults with severe 
widespread dystonia were treated with high doses of benzhexol (up to 130 mg 
daily introduced slowly over many weeks). Children tolerated higher doses 
(median 30 mg/day) than adults (median 20 mg/day). 52% of the children gained 
useful benefit, many (43%) without unwanted side effects. Such an approach was 
less successful in adults; 41% gained benefit, but only 35% had no side effects. 
Twelve adults with severe axial dystonia, and two children with life-threatening 
generalised dystonia were treated with a combination of a low constant dose of 
tetrabenazine to which were added pimozide and benzhexol as necessary. The dose 
of tetrabenazine was aimed at 75 mg daily; pimozide was increased (6 to 25 
mg/day) until the dystonia was relieved or Parkinsonism and other side-effects 
prevented further increments; if necessary benzhexol (6 to 30 mg/day) then was 
added to control side-effects and to provide additional benefit. 75% of the 
adults with severe axial dystonia, and one of the two children with life 
threatening generalised dystonia gained useful benefit from this regime. It is 
concluded that high dose benzhexol is the present first treatment of choice for 
children with severe dystonia, and is worth a try in adults but with less 
expectation of success. When benzhexol treatment alone fails in adults with 
severe disabling axial dystonia, or in children with life-threatening 
generalised dystonia, combined therapy with tetrabenazine, pimozide and 
benzhexol may give valuable symptomatic relief.