Interventions for people with schizophrenia who have too much saliva due to clozapine treatment

Clozapine is an antipsychotic medication used in the treatment of schizophrenia, a mental health problem that can cause symptoms such as hallucinations and delusions and social withdrawal. Clozapine may be useful in those for whom other medications have not worked very well. One of the common side-effects of clozapine is having too much saliva in the mouth (hypersalivation). This can be embarrassing in public and problematic, especially at night. This review is about ways of reducing this problem and includes 15 trials containing 964 people, most of which were done in hospitals in China. Treatments included medications that had previously been useful for this problem or were thought to work in theory. The medications used were from a group of drugs called antimuscarinics, traditional Chinese medicines or others. The trials were short (all four weeks or less). From these trials the antimuscarinics; astemizole, diphenhydramine and propantheline, were shown to be better than placebo at reducing hypersalivation. Another medication called oryzanol and a Chinese traditional medicine called Suo quo wan were found to have benefit over doxepin, an antimuscarinic. However, because of the shortness of the trials, poor reporting and the limitations of design, it is difficult to draw any firm conclusions from these results. 

(Plain language summary prepared for this review by Janey Antoniou of RETHINK, UK, www.rethink.org)