Anticholinergic medication for excessive salivation caused by use of antipsychotics other than clozapine

The first line of treatment of schizophrenia is usually antipsychotic drugs. These drugs help in the treatment of the ‘positive symptoms’ of schizophrenia, such as hearing voices, seeing things and having strange beliefs. However, these drugs often have serious side effects, such as weight gain, muscle stiffness, tiredness, apathy and lack of drive. Dribbling or drooling (hypersalivation) is another common side effect, which frequently occurs at night when asleep. This can be an embarrassing and stigmatising problem that can affect quality of life and cause people to stop their medication, which may result in relapse and going back into hospital. Dribbling and drooling can be difficult to treat; however, anticholinergic drugs can decrease production of saliva and dribbling. This review assessed the evidence for the benefit or harm of anticholinergic drugs used in treating hypersalivation caused by antipsychotic or neuroleptic medication. The review excluded the antipsychotic clozapine, as its role in causing hypersalivation has been the subject of another Cochrane review.


The search was carried out 15 November 2012 and resulted in identification of four potential studies, but none could be included. Three of these were excluded because they involved clozapine-related hypersalivation. The fourth study was excluded because it involved people with mood or other mental disorders and Chinese medicines. Dribbling or hypersalivation is an important problem that needs to be investigated via well-designed research and randomised trials. Until such time, psychiatrists and patients are likely to continue their treatment of hypersalivation on the basis of daily clinical judgement and personal experience rather than hard evidence. Treatment of hypersalivation caused by antipsychotics or neuroleptics other than clozapine does not seem to have received adequate research attention to help guide practice. The review authors conclude that using anticholinergics to treat dribbling or hypersalivation caused by antipsychotic drugs other than clozapine cannot be justified without further study.

This plain language summary has been written by Benjamin Gray, Service User and Service User Expert: Rethink Mental Illness. Email: ben.gray@rethink.org

 

Authors' conclusions: 

We have been unable to locate any studies addressing the question raised in this review. Accordingly, this empty review points out an important clinical problem that needs to be investigated via well-designed and well-conducted randomised trials. Clinicians and patients are likely to continue with their current dependence on clinical judgement and personal experience. Policy makers have no trial-based evidence upon which to base guidelines for the treatment of hypersalivation induced by neuroleptics other than clozapine. They are likely to continue to rely on opinion and habit when making recommendations. Funders of studies may wish to make this important subgroup of people a priority in future research.

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Background: 

Treatment of schizophrenia depends heavily on neuroleptic drugs. Hypersalivation is a common side effect when people with schizophrenia are treated with neuroleptic drugs. Hypersalivation can be an embarrassing and stigmatising problem, can affect quality of life and can result in discontinuation of neuroleptic treatment. It can also be difficult to treat.

Objectives: 

To summarise the best available evidence of the effects of anticholinergic drugs in the treatment of non-clozapine neuroleptic-induced hypersalivation in people with schizophrenia. Clozapine-induced hypersalivation has been addressed in another Cochrane review.

Search strategy: 

We searched the Cochrane Schizophrenia Group Trials Register (15 November 2012) and inspected references of all identified studies for further relevant studies. We were to contact the first author of each included study for information regarding unpublished trials.

Selection criteria: 

All randomised controlled trials comparing an anticholinergic drug with placebo, no treatment, another anticholinergic drug or any other intervention.

Data collection and analysis: 

We inspected the results of the search to identify relevant studies. We were to extract data onto standard, simple forms. Disagreements were resolved through discussion. The risk of bias was to be assessed using the Cochrane risk assessment tool. For binary outcomes, we were to calculate a standard estimation of the risk ratio (RR) and its 95% confidence interval (CI). For continuous outcomes, we were to estimate the mean difference between groups.

Main results: 

The search resulted in four potential studies; after inspection, all were excluded. Three studies were excluded because they involved people with clozapine-induced hypersalivation - a topic covered in another Cochrane review. The fourth study was excluded because it involved people with schizophrenia, mood disorders or other mental disorders who were suffering from clozapine- and non-clozapine induced hypersalivation and were treated with Chinese medicines with unknown anticholinergic properties. People in the control group received an anticholinergic drug (artane) or an antihistamine (phenergan). It was not possible to separate clozapine- from non-clozapine-treated people in the intervention group, or to separate artane-treated people from phenergan-treated people in the control group.

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