There is some support for the use of anticholinergic drugs as a prophylactic agents for the prevention of some EPS (e.g. acute dystonia) at the onset of neuroleptic therapy, however, a major issue which remains unresolved is the length of time maintenance treatment is required after an acute episode has been controlled with anticholinergic drugs. Controversy relating to the use of anticholinergic drugs for more than 3 months still remains, considering that approximately 50% of patients continue to have EPS while they remain on neuroleptic treatment. It is not possible to clearly distinguish those patients who will develop EPS after withdrawal of neuroleptics from those who will not.
The findings from research studies of anticholinergic withdrawal have not resolved the issue whether anticholinergic drugs should be continued long term. There is considerable variation in the relapse rates of EPS from studies on withdrawal of anticholinergic drugs (e.g. McClelland et al, 1974; Caroli et al, 1975). It is difficult to conclude from the research literature whether anticholinergic medication can be safely withdrawn without recurrence of EPS. It is difficult to find out the reason for this wide variation in different studies. Although most studies used long-stay patient samples with similar group of patients, some differences in results can probably be due to different methods used, however, it is likely that there are other non-specific underlying reasons than different samples (Double et al, 1993).
Rates of EPS depend upon drug factors, patient variables and time since initiation of neuroleptic treatment. Study of risk factors should guide prophylactic use, initiation and maintenance treatment with anticholinergic drugs. The treatment options for management of neuroleptic-induced EPS have to be flexible.