The Effects of Bethanechol on Anticholinergic Side Effects of Haloperidol

Son, Seung Chan; Kim, Jin Se; Kim, Seung Hyun; Joe, Sook Haeng; Choi, Young Tae

Abstract

OBJECTIVES
Haloperidol has been widely used for treating schizophrenia with somewhat limitation due to the side effects. Some of these side effects are anticholinergic side effects such as dry mouth, constipation, urinary difficulty, blurred vision, sexual dysfunction, etc. Some kinds strategies to minimize these side effects are tried, one of which is the use of bethanechol. The authors studied the effects of bethanechol on the anticholinergic side effects of typical antipsychotics.
METHODS
The subjects of this study consisted of 60 chronic schizophrenics who had used haloperidol since 4 weeks before the study and whose score of 'Askers side effects rating scale' was above 7. They were assigned evenly to three groups (placebo group, bethanechol 40mg group, bethanechol 80mg group). Benztropin had been washed out for 2 weeks before the study. The authors measured ASRS for evaluating the anticholinergic side effect and BPRS for evaluating the effects of bethanechol on the psychopathology, at baseline, the 2nd week and the 4th week from baseline, respectively.
RESULTS
At baseline, the mean age of patients was 38.00(+/- 10.55) years, the mean duration of illness was 11.12(+/- 8.09) years, and the mean dosage of the haloperidol was 15.07(+/- 6.03)mg. At baseline, mean score of BFRS was 50.25(+/- 5.24), and mean score of ASRS was 9.27 (+/- 3.04). There were no significant differences of ages, duration of illness, dosage of haloperidol, scores of BPRS and ASRS among 3 groups at baseline. There were no significant changes in BPRS at the 2nd week and the 4th week as compared with baseline, and also there were no changes among groups. The total sums of ASRS showed the statistically significant changes in the 80mg group at the 2nd week and the 4th week. The 80mg group showed statistically significant changes in dry mouth, constipation and urinary difficulty dom the 2nd week, and orthostatic symptoms from the 4th week.
CONCLUSION
The authors found that the use of bethanechol for the chronic schizophrenics treating with haloperidol greatly improved the anticholinergic side effects with no change in psychopathology. The 80mg group showed more significant results than the placebo group and the 40mg group, especially in dry mouth, constipation, urinary diffculty and orthostatic symptoms. The authors suggest that high doses of bethanechol decrease the anticholinergic side effects and increase the drug compliance of chronic schizophrenics with anticholinergic side effects.