The effect of clozapine on saliva flow rate: a pilot study

Prevalence of clozapine-induced sialorrhea and its effect on quality of life

RATIONALE

Clozapine has proven to be superior to other antipsychotic drugs in the treatment of schizophrenia but is under-prescribed due to its potentially severe side effects. Clozapine-induced sialorrhea (CIS) is a frequent and extremely uncomfortable side effect, which remains understudied.

OBJECTIVES

To examine the prevalence of diurnal and nocturnal CIS in a sample of patients treated with clozapine, and to evaluate its impact on quality of life.

METHODS

We conducted a cross-sectional, observational study of 130 patients with schizophrenia spectrum disorders treated with clozapine. The prevalence of CIS was evaluated via specific sialorrhea scales. None of the patients included in the study was receiving a specific treatment for hypersalivation during the study period. Possible associations between sialorrhea and clinical and quality of life variables were analyzed.

RESULTS

Of 130 subjects, 120 (92.3%) suffered from CIS. Eighty-one (62.31%) suffered from diurnal CIS, 115 (88.56%) from nocturnal CIS, and 85 (65.38%) suffered from both. Significant positive associations between quality of life and diurnal CIS (B = 0.417; p = 2.1e - 6, R² = 0.156) and nocturnal CIS (B = 0.411; p = 7.7e - 6, R² = 0.139) were detected. Thirty per cent of the subjects reported a moderate to severe negative impact of sialorrhea on their quality of life.

CONCLUSIONS

The present study suggests that CIS is highly prevalent in patients with schizophrenia and has an important impact on quality of life in one-third of our sample. Therefore, the inclusion of a systematic evaluation and treatment of CIS in standard clinical practice is highly recommended.

TRIAL REGISTRATION

Clinical Trials ( https://clinicaltrials.gov ) under reference NCT04197037.

A retrospective case notes review of the effectiveness and tolerability of metoclopramide in the treatment of clozapine-induced hypersalivation (CIH)

OBJECTIVE

The objective of the study is to explore the long-term effectiveness and tolerability of metoclopramide in the treatment of CIH.

METHOD

This study is a retrospective, observational cohort study of patients prescribed metoclopramide for CIH at the South London & Maudsley (SLaM) NHS Foundation Trust.

RESULTS

Of the 96 patients identified, 14 patients were eligible for inclusion in our study. Five patients continued treatment with a mean duration of 27 months (SD = 17.8), and one patient continued until transfer with a duration of 3 months. Eight patients discontinued treatment after a mean duration of 8 months.

CONCLUSION

Metoclopramide may be an effective and tolerated drug in CIH, but more data is required to establish its place in the pharmacotherapy of this condition.

Association Between N-Desmethylclozapine and Clozapine-Induced Sialorrhea: Involvement of Increased Nocturnal Salivary Secretion via Muscarinic Receptors by N-Desmethylclozapine

Clozapine-induced sialorrhea (CIS) is a common side effect of clozapine. There is no established standard treatment of CIS since the underlying mechanism remains unknown. This study aimed to elucidate the mechanisms involved in CIS. In our clinical study, a prospective observational study evaluated the association between serum and saliva concentrations of clozapine or its metabolites and Drooling Severity and Frequency Scale (DSFS) score. In our in vivo study, we first developed a new CIS animal model; subsequently, we measured salivary secretion and concentrations of clozapine or its metabolites in the animal model. In our in vitro study, we measured the calcium ion (Ca²⁺) response to evaluate the effect of clozapine or its metabolites on human salivary gland cell line (HSY cells) and then examined whether their effect was inhibited by atropine. In our clinical study, serum and saliva N-desmethylclozapine concentrations were significantly correlated with nocturnal DSFS score. In our in vivo study, daily single oral administration of 100 mg/kg clozapine for 7 days significantly increased salivary secretion in rats. Furthermore, N-desmethylclozapine concentrations in serum and submandibular glands of the rats were higher than clozapine concentrations. In our in vitro study, N-desmethylclozapine only elicited an increase in the intracellular Ca²⁺ in HSY cells. N-desmethylclozapine-induced Ca²⁺ responses were inhibited by atropine. These results suggest that N-desmethylclozapine is implicated in CIS by increasing nocturnal salivation via the muscarinic receptors. Moreover, our developed animal model that reflects CIS in clinical condition plays a key role as a bridge between basic and clinical research. SIGNIFICANCE STATEMENT: Clozapine-induced sialorrhea (CIS) is a severe and frequent adverse reaction, but the mechanism underlying CIS is less well understood. This paper reports that N-desmethylclozapine, a metabolite of clozapine, is implicated in CIS by increasing nocturnal salivation via the muscarinic receptors and that oral administration of clozapine at 100 mg/kg once daily for 7 days to rat is the optimum method for establishing the new animal model reflecting the clinical scenario of CIS.

Initiating clozapine treatment service and characteristics of clozapine-treated patients in a general hospital in Addis Ababa, Ethiopia

Background

At least one-third of patients with schizophrenia suffer from treatment-resistant schizophrenia needing treatment with clozapine. This is the first report on the experience of initiating clozapine service in Ethiopia.

Aim

The aim of this study was to report the experience of setting up clozapine service and describe characteristics of patients treated with clozapine.

Setting

This study was conducted in a general hospital in Addis Ababa, Ethiopia.

Methods

Descriptive summary of the clozapine treatment service and review of characteristics of patients treated with clozapine were conducted. Clinical Global Impression (CGI) Scale and Abnormal Involuntary Movement Scale (AIMS) score were used to measure outcome. Quantitative data were analysed using Statistical Package for the Social Sciences (SPSS) Version 24.

Results

It was possible to provide clozapine treatment in a general hospital using the national guideline. During the first year of initiation of the service, a total of 22 patients were treated. The majority were men (20/22, 90.9%) and in the age group of 30–44 years (11/22, 50%). Indications for clozapine were treatment-resistant schizophrenia (15/22, 68.2%) and tardive dyskinesia (7/22, 31.8%). The average dose of clozapine was 350 mg/day. Common side effects included sedation, constipation and excessive salivation. On CGI Scale, mean severity index score dropped from 5.18 at admission to 3.68 during discharge, and average AIMS score changed from 16.8 to 6.5. None of the patients developed agranulocytosis; however, three patients discontinued because of adverse effects.

Conclusion

Establishing clozapine treatment service was possible in a general hospital in Ethiopia where psychiatric service run by psychiatrists was available. Mechanisms should be in place to ensure adherence to the national guideline.

Treatment Strategies for Clozapine-Induced Sialorrhea: A Systematic Review and Meta-analysis

BACKGROUND

Clozapine is the most effective medication for treatment-refractory schizophrenia. However, it has a high burden of adverse events, including common adverse events such as sialorrhea. Sialorrhea can lead to severe physical complications such as aspiration pneumonia, as well as psychological complications including embarrassment and low self-esteem. Compromised adherence and treatment discontinuation can occur due to intolerability. There have been no meta-analyses examining strategies to mitigate clozapine-induced sialorrhea.

METHODS

We systematically searched Chinese and Western research databases for randomised controlled trials examining agents for clozapine-induced sialorrhea. No limit to language or date were applied to the search. Where sufficient data for individual agents was available, pairwise meta-analyses were conducted. Results were provided as risk ratios and number needed to treat. Sensitivity analysis was conducted by study quality. Adverse events were provided as number needed to harm.

RESULTS

19 studies provided data for use in the meta-analysis. Improvement in clozapine-induced sialorrhea was seen in meta-analyses of propantheline (studies = 6, risk ratio [RR] 2.38, 95% confidence interval [CI] 1.52-3.73; number needed to treat [NNT] 3, 95% CI 1.9-2.7), diphenhydramine (studies = 5, RR 3.09, 95% CI 2.36-4.03; NNT 2, 95% CI 1.5-2.0), chlorpheniramine (studies = 2, RR 2.37, 95% CI 1.59-3.55; NNT 3, 95% CI 1.6-3.5), and benzamide derivatives (odds ratio [OR] 6.93, 95% CI 3.03-15.86). When meta-analyses were limited to high-quality studies, all these results remained significant. Single studies of benzhexol, cyproheptadine, doxepin and Kongyan Tang showed promise. Propantheline increased rates of constipation with a number needed to harm (NNH) of 9 (95% CI 4.2-204.1).

CONCLUSION

Clozapine-induced sialorrhea is a potentially serious adverse event. Included studies in this meta-analysis were limited by poor study quality. Diphenhydramine, chlorpheniramine and benzamide derivatives appear to have the best supporting evidence and lowest reported adverse events. Caution should be exercised when using propantheline given its increased risk of constipation.

Antipsychotic drug use and pneumonia: Systematic review and meta-analysis

OBJECTIVES

The purpose of this study was to investigate the association of antipsychotic exposure to the incidence and mortality of pneumonia.

METHODS

The design of this study involved meta-analysis of observational studies identified from electronic databases.

RESULTS

In total, 19 studies were included in the systematic review and 14 in the meta-analysis. Risk of pneumonia was increased by first-generation antipsychotics (risk ratio 1.69, 95% confidence interval 1.34-2.15; five studies), second-generation antipsychotics (risk ratio 1.93, 95% confidence interval 1.55-2.41; six studies) and all antipsychotics (risk ratio 1.83, 95% confidence interval 1.60-2.10; seven studies) compared with no antipsychotic use. Pneumonia risk did not differ in seven studies comparing first-generation antipsychotics with second-generation antipsychotics (risk ratio 1.07, 95% confidence interval 0.85-1.35). Case fatality rate was not different in pneumonia cases associated with antipsychotic exposure versus cases without exposure (risk ratio 1.50; 95% confidence interval 0.76-2.96; two studies). All antipsychotics with data from ⩾2 studies allowing meta-analysis, were associated with a significantly increased pneumonia risk (i.e. haloperidol, olanzapine, clozapine, risperidone, quetiapine, zotepine).

CONCLUSION

Exposure to both first-generation antipsychotics and second-generation antipsychotics is associated with an increased pneumonia risk. Clinicians need to be vigilant for the occurrence of pneumonia in patients commencing antipsychotics, especially those with other risk factors for pneumonia including older age, chronic respiratory disease, cerebrovascular disease, dysphagia and smoking.

A review of the treatment options for clozapine-induced hypersalivation

Aims and Method

To develop and introduce an evidence-based drug treatment protocol for clozapine-induced hypersalivation, a review of published literature relating to clozapine-induced hypersalivation and its treatment was undertaken in March 2000. The databases searched were Medline, EMBASE and PsychLit, from 1966 to the present.

Results

This paper reviews the evidence of the benefit of using antimuscarinic agents, adrenergic antagonists and adrenergic agonists. There is alack of good-quality controlled-trials, with most papers reporting aseries of uncontrolled cases dependent on subjective measures of improvement reported by the patients. However, the published literature suggests a benefit for all of the drug categories reviewed. The most effective treatment may be acombination of terazosin and benzhexol.

Clinical Implications

Clozapine-induced hypersalivation is not only an embarrassing problem, but can be difficult to treat. An evidence-based prescribing protocol will encourage the use of those drugs found to be the most effective in treating this problem. It will also offer alternatives if acertain treatment is ineffective or intolerable.

The Effect of Glycopyrrolate on Nocturnal Sialorrhea in Patients Using Clozapine: A Randomized, Crossover, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Nocturnal sialorrhea is one of the most frequent adverse events in clozapine treatment. Symptomatic management of sialorrhea usually consists of off-label treatment with anticholinergic agents. The aim of the current study is to evaluate the efficacy and safety of glycopyrrolate in patients using clozapine that experience sialorrhea.

METHODS

In a double-blind randomized crossover trial, patients with nocturnal sialorrhea (n = 32) were randomized to treatment with glycopyrrolate 1 mg or placebo. This double-blinded phase was followed by an optional open label extension phase with glycopyrrolate 2 mg. Exposure periods consisted of 6 consecutive days and were separated with 1 washout week. The primary outcome was clinical improvement of nocturnal sialorrhea assessed by the Patient Global Impression of Improvement (PGI-I).

RESULTS

The proportion of patients with a clinical improvement according to PGI-I did not significantly differ between 1 mg and placebo (18.8% vs 6.3%, P = 0.289); however, in patients using glycopyrrolate 2 mg once daily versus placebo, it did (43.5% vs 6.3%, P = 0.039). Glycopyrrolate was not associated with severe adverse events or worsening of cognitive adverse events.

CONCLUSIONS

Glycopyrrolate 1 mg was not superior to placebo, whereas 2 mg showed a significant clinical improvement of nocturnal sialorrhea compared with placebo. Glycopyrrolate seemed to be a tolerable anticholinergic agent in the treatment of clozapine-associated sialorrhea.

Polymorphism in alpha 2A adrenergic receptor gene is associated with sialorrhea in schizophrenia patients on clozapine treatment

OBJECTIVE

Clozapine-induced sialorrhea (CIS) is a common, inconvenient and socially stigmatizing adverse effect. The pathophysiology of CIS may be related to the effect of clozapine on the muscarinic and adrenergic receptors as well as the disruption of the circadian rhythms. The aim of this study was to find out if polymorphisms in muscarinic M1 and M3 receptor genes (CHRM1 and CHRM3), adrenoceptor alpha 2A gene (ADRA2A) or clock circadian regulator gene (CLOCK) are associated with CIS.

METHODS

Two hundred and thirty-seven clozapine-treated Finnish schizophrenia patients were genotyped for CHRM1, CHRM3, CLOCK and ADRA2A polymorphisms, and their salivary dysfunction was assessed with two questions. Twenty-six of these patients had previously been on medication to treat CIS. Comparisons of the genotypes between patients with excessive versus non-excessive salivation were analysed. Genotype distributions between patients and control group and haplotypes were also studied.

RESULTS

CHRM1, CHRM3 and CLOCK polymorphisms and haplotypes were not associated with CIS. ADRA2A (rs1800544) genotype was associated with CIS (p = 0.029). In patients with CIS, CC genotype (n = 103) was more common than in G-allele carriers (n = 79) (p = 0.013, OR 2.13, 95% CI: 1.17-3.88). No differences were found in the distributions of genotypes between patients and controls.

CONCLUSIONS

ADRA2A genotype was associated with CIS.

Physical comorbidity and its relevance on mortality in schizophrenia: a naturalistic 12-year follow-up in general hospital admissions

Schizophrenia is a major psychotic disorder with significant comorbidity and mortality. Patients with schizophrenia are said to suffer more type-2 diabetes mellitus (T2DM) and diabetogenic complications. However, there is little consistent evidence that comorbidity with physical diseases leads to excess mortality in schizophrenic patients. Consequently, we investigated whether the burden of physical comorbidity and its relevance on hospital mortality differed between patients with and without schizophrenia in a 12-year follow-up in general hospital admissions. During 1 January 2000 and 31 June 2012, 1418 adult patients with schizophrenia were admitted to three General Manchester NHS Hospitals. All comorbid diseases with a prevalemce ≥1% were compared with those of 14,180 age- and gender-matched hospital controls. Risk factors, i.e. comorbid diseases that were predictors for general hospital mortality were identified using multivariate logistic regression analyses. Compared with controls, schizophrenic patients had a higher proportion of emergency admissions (69.8 vs. 43.0%), an extended average length of stay at index hospitalization (8.1 vs. 3.4 days), a higher number of hospital admissions (11.5 vs. 6.3), a shorter length of survival (1895 vs. 2161 days), and a nearly twofold increased mortality rate (18.0 vs. 9.7%). Schizophrenic patients suffered more depression, T2DM, alcohol abuse, asthma, COPD, and twenty-three more diseases, many of them diabetic-related complications or other environmentally influenced conditions. In contrast, hypertension, cataract, angina, and hyperlipidaemia were less prevalent in the schizophrenia population compared to the control population. In deceased schizophrenic patients, T2DM was the most frequently recorded comorbidity, contributing to 31.4% of hospital deaths (only 14.4% of schizophrenic patients with comorbid T2DM survived the study period). Further predictors of general hospital mortality in schizophrenia were found to be alcoholic liver disease (OR = 10.3), parkinsonism (OR = 5.0), T1DM (OR = 3.8), non-specific renal failure (OR = 3.5), ischaemic stroke (OR = 3.3), pneumonia (OR = 3.0), iron-deficiency anaemia (OR = 2.8), COPD (OR = 2.8), and bronchitis (OR = 2.6). There were no significant differences in their impact on hospital mortality compared to control subjects with the same diseases except parkinsonism which was associated with higher mortality in the schizophrenia population compared with the control population. The prevalence of parkinsonism was significantly elevated in the 255 deceased schizophrenic patients (5.5 %) than in those 1,163 surviving the study period (0.8 %, OR = 5.0) and deceased schizophrenic patients had significantly more suffered extrapyramidal symptoms than deceased control subjects (5.5 vs. 1.5 %). Therefore patients with schizophrenia have a higher burden of physical comorbidity that is associated with a worse outcome in a 12-year follow-up of mortality in general hospitals compared with hospital controls. However, schizophrenic patients die of the same physical diseases as their peers without schizophrenia. The most relevant physical risk factors of general hospital mortality are T2DM, COPD and infectious respiratory complications, iron-deficiency anaemia, T1DM, unspecific renal failure, ischaemic stroke, and alcoholic liver disease. Additionally, parkinsonism is a major risk factor for general hospital mortality in schizophrenia. Thus, optimal monitoring and management of acute T2DM and COPD with its infectious respiratory complications, as well as the accurate detection and management of iron-deficiency anaemia, of diabetic-related long-term micro- and macrovascular complications, of alcoholic liver disease, and of extrapyramidal symptoms are of utmost relevance in schizophrenia.

[Clozapine-induced parotitis: a case study]

INTRODUCTION

Clozapine is the drug of choice for patients with an unsatisfactory response to routine antipsychotic treatment. Side effects such as sedation, weight gain, hypotension and hypersialorrhea are frequently reported whereas clozapine-induced parotitis is a less known complication.

CASE REPORT

We report the case of a 32-year-old woman with a refractory schizoaffective disorder, bipolar type. The failure to respond to at least two well-conducted antipsychotic trials with flupentixol and risperidone, led clinicians to prescribe clozapine, which was started three years earlier. Since its introduction, clozapine induced sialorrhea, which has been managed until now with anticholinergic medication. Recently, Mrs B. was hospitalized for a new relapse. Once treatment compliance checked (good level of plasmatic dosage), we decided to increase the dose of clozapine from 350 mg/d to 500 mg/d. Twenty days later, Mrs B. exhibited improvement of symptoms but complained of acute bilateral auricular pain and odynophagia. The bilateral and comparative clinical exam displayed a bilateral filling of the retromandibular depression, the painful swelling of the parotid gland, along with ptyalism and a slight inflammatory oedema of the Stenon duct orifice. Mrs B. was apyretic, with physiological constants within the limits of normal values. The biological analyses displayed a discrete inflammatory syndrome (mild hyperleucocytosis and anemia), a negative mumps IgM test and positive mumps IgG test, and a 1050 ng/mL clozapine blood level. Once viral parotitis was ruled out, the involvement of clozapine was evoked. Symptomatic medication was prescribed with per os analgesic (paracetamol) and antiseptic mouthwash (Éludril). Clozapine dosage was lowered to 400 mg/d. A week later, clinical examination confirmed improvement of the medical and psychiatric conditions.

DISCUSSION

We report the case of a patient who developed a parotitis following clozapine dose adjustment. Clozapine induced parotitis was retained once the infectious and other organic etiologies had been ruled out. Previous cases of clozapine-induced parotitis have already been reported and we have some arguments to suspect this etiology in our case. First, Mrs B. experienced more hypersialorrhea with the increase in clozapine dosage. Second, the anticholinergic medication was interrupted 3 days before the episode of parotitis. Two main pathophysiological hypotheses, immune and inflammatory, have already been proposed to explain clozapine-induced parotitis. In the former, the immunomodulating properties of clozapine may sensitize the mononuclear blood cells, leading to the sialadenitis. The latter hypothesis is the more documented and proposes that clozapine-induced hypersialorrhea may be responsible for a chronic inflammatory state that can lead to the formation of a parotid lithiasis and consequently parotitis. This case report illustrates clozapine induced-parotitis, a poorly known complication of this compound. Clinicians should be aware of its hypersialorrhea and inflammatory consequences in order to better prevent the occurrence of this complication.

Atypical antipsychotics--effects of amisulpride on salivary secretion and on clozapine-induced sialorrhea

OBJECTIVE

Amisulpride is suggested for treatment of clozapine-induced sialorrhea. However, objective measurements of its effectiveness are lacking and, preclinically, amisulpride has no effect. We currently hypothesise that amisulpride acts by reducing the nervous- rather than the clozapine-driven salivary secretion.

MATERIAL AND METHODS

Effects of intravenous amisulpride (as well as of clozapine and raclopride, a dopamine D2/D3 antagonist) were investigated in rats, including those subjected to chronic preganglionic parasympathetic denervation (submandibular glands) or combined postganglionic parasympathetic and sympathetic denervation (parotid glands). In duct-cannulated glands, secretion was evoked reflexly, at low and maximum flow rates, and by electrical stimulation of the parasympathetic and sympathetic innervations, and administration of autonomimetics (including substance P).

RESULTS

Unlike clozapine, amisulpride had no effect on the reflexly evoked secretion at maximum rate. With respect to reflex secretion at low rate and to the secretion evoked by muscarinic, α-adrenergic, β-adrenergic and substance P receptors, amisulpride (in contrast to raclopride) dose dependently potentiated the responses. Amisulpride had no effect on gland blood flow.

CONCLUSIONS

No support for any inhibitory influence of amisulpride was found. Conversely, amisulpride universally enhanced secretion, suggesting that amisulpride is a potential drug for dry-mouth treatment. The mechanism behind the potentiation is currently unknown.

Clozapine-induced salivation: interaction with N-desmethylclozapine and amisulpride in an experimental rat model

Many drugs (e.g. amisulpride) have been used to treat troublesome clozapine-induced salivation; however, varying success has been achieved in this respect, probably because, until recently, the salivatory action of clozapine has been largely unexplained. In the rat, clozapine and its main metabolite, N-desmethylclozapine, were found to exert mixed secretory actions: excitatory, through muscarinic acetylcholine M1-receptors giving rise to a long-lasting, low-level flow of saliva; and inhibitory, through muscarinic M3-receptors and α(1) -adrenoceptors reducing the parasympathetically and sympathetically nerve-evoked flow of saliva. The aim of the present study was to define the interactions between clozapine and N-desmethylclozapine, and clozapine and amisulpride, with respect to the excitatory response. Submandibular glands, sensitized by chronic parasympathetic preganglionic denervation, were studied in pentobarbitone-anaesthetized rats. To prevent clozapine from being metabolized to N-desmethylclozapine by hepatic enzymes, the liver was, under terminal anaesthesia, excluded from the circulation. The weak receptor-stimulating clozapine prevented the strong receptor-stimulating N-desmethylclozapine, at specific ratios in humans and in rats, from exerting its full agonistic action. In conclusion, the contribution of N-desmethylclozapine to the clozapine-induced sialorrhoea was, at most, only partly additive. Furthermore, the present experimental set-up failed to demonstrate any anti-salivatory action of amisulpride on the clozapine-induced flow of saliva.

Clozapine: Agonistic and Antagonistic Salivary Secretory Actions

Individuals receiving clozapine treatment for schizophrenia complain of drooling. Reports on salivary flow measurements are contradictory in humans and lacking in animals. Clozapine has affinity for several different receptor types and may, hypothetically, both stimulate and inhibit salivary secretion. In rats, intravenous clozapine evoked a long-lasting secretion, being more prominent from submandibular than from parotid glands. Chronic denervation enhanced the responses. Clozapine acted on muscarinic (M1-) receptors of acinar cells, independent of central nervous mechanisms, pre-synaptic intraglandular events, or circulating catecholamines. A fraction of the methacholine- and parasympathetic-nerve-evoked secretion was abolished by clozapine at doses below those evoking secretion. Sympathetic-nerve-evoked secretion was partially reduced by clozapine, due to antagonistic action on α-adrenoceptors; the β-adrenoceptor-mediated response persisted. Subsecretory doses of clozapine enhanced secretion induced by the β-adrenoceptor agonist isoprenaline. The overall actions of clozapine suggest that, in clozapine-treated humans, salivation is increased during sleep and at rest, but is decreased during meals.

Pharmacological interventions for clozapine-induced hypersalivation

BACKGROUND

Clozapine is widely used for people with schizophrenia. Although agranulocytosis, weight gain, and cardiac problems are serious problems associated with its use, hypersalivation, sometimes of a gross and socially unacceptable quantity, is also common (30-80%).

OBJECTIVES

To determine the clinical effects of pharmacological interventions for clozapine-induced hypersalivation.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group Trials Register (March 2007), inspected references of all identified studies for further trials, contacted relevant pharmaceutical companies, drug approval agencies and authors of trials.

SELECTION CRITERIA

We included randomised controlled trials comparing pharmacological interventions, at any dose and by any route of administration, for clozapine-induced hypersalivation.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data (homogenous) we calculated relative risk (RR) with 95% confidence intervals (CI) and numbers needed to treat (NNT) on an intention-to-treat basis. We calculated weighted mean difference (WMD) for continuous data.

MAIN RESULTS

Of the 15 trials identified, 14 were conducted in China and 14 in hospitals. The quality of reporting was poor with no studies clearly describing allocation concealment and much data were missing or unusable. All results are vulnerable to considerable bias. Most frequently the primary outcome was the diameter of the wet patch on the pillow. Antimuscarinics (astemizole, diphenhydramine, propantheline, doxepin) were the most commonly evaluated drugs. For the outcome of 'no clinically important improvement' astemizole and diphenhydramine were more effective than placebo (astemizole: n=97, 2 RCTs, RR 0.61 CI 0.47 to 0.81 NNT 3 CI 2 to 5; diphenhydramine: n=131, 2 RCTs, RR 0.43 CI 0.31 to 0.58, NNT 2 CI 1.5 to 2.5), but the doses of astemizole used were those that can cause toxicity. Data involving propantheline were heterogeneous (I2= 86.6%), but both studies showed benefit over placebo. Adverse effects were poorly recorded. Of the other interventions, oryzanol (rice bran oil and rice embryo oil extract) showed benefit over the antimuscarinic doxepin in terms of 'no clinically important change' (n=104, 1 RCT, RR 0.45 CI 0.27 to 0.75, NNT 4 CI 2 to 7). The Chinese medicine suo quo wan (comprises spicebush root, Chinese yam and bitter cardamom) showed benefit over doxepin (n=70, 1 RCT, RR 'no clinically important change' 0.31 CI 0.16 to 0.59, NNT 3 CI 1.5 to 3.7).

AUTHORS' CONCLUSIONS

There are currently insufficient data to confidently inform clinical practice. The limitations of these studies are plentiful and the risk of bias is high. These trials, however, are invaluable guides for current and future study design. Well conducted randomised trials are possible. Some may be underway. Current practice outside of well designed randomised trials should be clearly justified.

Clozapine: Current perspective

The author conducted a review of studies that compared the efficacy, tolerability and indication for the use of clozapine in current perspectives for the treatment of resistant schizophrenia/ partial responders.

Clozapine-induced hypersalivation: a review of treatment strategies

OBJECTIVE

Clozapine-induced hypersalivation (CIH) is a significant side effect affecting about one-third of patients treated with clozapine. CIH can be stigmatizing, can affect quality of life, and can result in discontinuation of clozapine treatment. The purpose of this review is to provide an understanding of CIH, specifically, its pathophysiology, measurement, and the evidence for CIH treatment alternatives.

METHODS

We searched MEDLINE from 1980 to June 2006 for all reported pharmacologic treatment studies related to CIH. We identified additional references by a manual search of the bibliographies of retrieved articles.

RESULTS

Several studies reported improvement of CIH with both selective and nonselective anticholinergic medications. However, with the exception of local anticholinergic agents such as ipratropium bromide and atropine eye drops, potential systemic adverse effects limit the effectiveness of this class of medications. Open-label studies of clonidine, an alpha2 antagonist, suggest that it may be beneficial in managing CIH. Other pharmacologic treatments, such as amisulpride and botulinum toxin, may be useful in refractory CIH cases.

CONCLUSION

Although few randomized controlled trials were found in the literature, this review highlights potential treatment alternatives for this common and disabling cause of hypersalivation. Prompt and effective treatment of CIH may assist with treatment tolerability, adherence, and outcomes in patients with treatment-refractory schizophrenia. Information on funding and support and author affiliations appears at the end of the article.

Clozapine-induced sialorrhea: pathophysiology and management strategies

RATIONALE

Clozapine is an atypical antipsychotic agent with proven efficacy in refractory schizophrenia, but its widespread use is limited by adverse effects such as agranulocytosis, seizures, sedation, weight gain, and sialorrhea. Clozapine-induced sialorrhea (CIS) is bothersome and has socially stigmatizing adverse effects, which result in poor treatment compliance. The pathophysiology of this condition is poorly understood and the treatment options available are based mostly on case reports and open-label studies.

OBJECTIVE

To review the available studies on CIS.

METHOD

All relevant studies available through PUBMED search supplemented with manual search were undertaken.

RESULT

The clinical features, complications, assessment, pathophysiology, and management of CIS are discussed.

CONCLUSION

Although the studies evaluating the therapeutic options has limitations and no drug has been found to be superior, judicious use of pharmacological agents along with behavioral methods will reduce this troublesome side effect and enhance compliance.

A review of clozapine safety

Clozapine is a distinctive antipsychotic agent, having a unique clinical profile and an idiosyncratic safety profile. More so than with other agents, the weighting of its adverse event profile is critical, in order to counterbalance its clear clinical advantages. The safety issues with clozapine are in a number of areas, some of which are considered medical emergencies and potentially life-threatening. These include haematological (neutropenia and agranulocytosis), CNS (seizures), cardiovascular (myocarditis and cardiomyopathy), metabolic (diabetes), gastrointestinal and neuromuscular. Understanding the safety profile of clozapine allows an informed use of the agent that can maximise its clear clinical benefit and minimise the known risks.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia, Part 1: acute treatment of schizophrenia

These guide lines for the biological treatment of schizophrenia were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBO). The goal during the development of these guidelines was to review systematically all available evidence pertaining to the treatment of schizophrenia, and to reach a consensus on a series of practice recommendations that are clinically and scientifically meaningful based on the available evidence. These guidelines are intended for use by all physicians seeing and treating people with schizophrenia. The data used for developing these guidelines have been extracted primarily from various national treatment guidelines and panels for schizophrenia, as well as from meta-analyses, reviews and randomised clinical trials on the efficacy of pharmacological and other biological treatment interventions identified by a search of the MEDLINE database and Cochrane Library. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into four levels of evidence (A-D). This first part of the guidelines covers disease definition, classification, epidemiology and course of schizophrenia, as well as the management of the acute phase treatment. These guidelines are primarily concerned with the biological treatment (including antipsychotic medication, other pharmacological treatment options, electroconvulsive therapy, adjunctive and novel therapeutic strategies) of adults suffering from schizophrenia.

Regulation by clozapine of calcium handling by rat submandibular acinar cells

The effect of clozapine on the intracellular concentration of calcium ([Ca2+](i)) in rat submandibular acinar cells was tested. By itself clozapine had no effect on the mobilization of intracellular pools of calcium or on the uptake of extracellular calcium. It inhibited the increase of the [Ca2+](i) in response to carbachol (half-maximal inhibitory concentrations, IC(50)=100nM) and to norepinephrine and epinephrine (IC(50)=10nM) without affecting the response to substance P, extracellular ATP or thapsigargin. Clozapine inhibited the uptake of extracellular calcium in response to epinephrine but not to substance P, ATP or thapsigargin. It also decreased the production of inositol phosphates elicited by epinephrine but not by substance P or fluoride. It is concluded that, by itself, clozapine has no effect on the [Ca2+](i) in rat salivary acinar cells. It selectively inhibits muscarinic and adrenergic receptors in the acinar plasma membrane.

Therapeutic effect of pirenzepine for clozapine-induced hypersalivation: a randomized, double-blind, placebo-controlled, cross-over study

The objective of this study was to investigate the efficacy of pirenzepine in the treatment of clozapine-induced hypersalivation. Pirenzepine is reported to counteract hypersalivation by its selective antagonistic activity on the M4-muscarinic receptor, which is stimulated by clozapine. Twenty patients with clozapine-induced hypersalivation underwent a random-order, double-blind, placebo-controlled, cross-over trial which lasted 8 weeks each for the pirenzepine and placebo investigations, with a 4-week washout period in between. The severity of hypersalivation was assessed using an objective measure: saliva production monitored through the diameter of wetted surface on tissue paper placed over the patient's pillow. Our study showed that pirenzepine had no significant therapeutic effect on hypersalivation compared with placebo, suggesting that hypersalivation induced by clozapine might have a neurobiological basis other than the M4-muscarinic receptor.

Therapeutic options in the treatment of clozapine-induced sialorrhea

Clozapine is an effective atypical antipsychotic drug, but its use may be compromised by its side effects. Agranulocytosis may be fatal, but sialorrhea occurs more frequently and plays a major role in patients' noncompliance. A MEDLINE search from 1975-2000 revealed that treatment of clozapine-induced sialorrhea is predominantly based on case reports. Due to its elusive mechanism, physicians have attempted to treat this side effect with agents that counteract clozapine's adrenergic and muscarinic properties. We evaluated reported treatment options and other possible strategies from a pharmacologic standpoint. Antimuscarinic agents and alpha-receptor agonists are both viable options but must be administered and monitored cautiously in patients with psychiatric disorders. Although not yet available in the United States, pirenzepine, a selective muscarinic receptor antagonist, has the most promising mechanism. Other selective, peripherally acting agents must be investigated in controlled clinical trials to determine their efficacy as possible alternatives.

Pharmacological and molecular targets in the search for novel antipsychotics

The recent enthusiasm among clinicians for the so-called 'atypical antipsychotics' has both improved treatment for schizophrenic patients and provided a welcome stimulus for basic research on antipsychotic mechanisms. Even the newer drugs have shortcomings, and research is underway aimed at identifying novel agents with greater efficacy and safety. Much of this effort is directed towards compounds which, in addition to blocking dopamine receptors, also act on other neurotransmitter receptors such as 5-HT2, 5-HT1A and alpha2-adrenergic receptors. However, there is also a large amount of scientific activity seeking to discover and develop selective dopamine receptor subtype antagonists (including compounds which specifically block D3 or D4 receptors) or drugs that specifically target the dopamine autoreceptor. Finally, a number of drug development programmes are searching for non-dopaminergic antipsychotics. Drugs that do not have affinity for dopamine receptors but act through neurotensin, sigma or cannabinoid CB1 receptors or glutamatergic mechanisms are currently being evaluated. If any of these agents prove to have clinical efficacy this may lead to a third generation of antipsychotics. It is likely, however, that the mechanisms of action of such drugs will nevertheless imply the intimate involvement of dopaminergic pathways.

Clozapine-induced hypersalivation

OBJECTIVE

To review underlying pathophysiology and possible treatments for clozapine-induced hypersalivation.

DATA SOURCES

Primary literature was accessed through MEDLINE (1966-May 1999). Key search terms included clozapine, hypersalivation, sialorrhea, and treatment.

DATA SYNTHESIS

Hypersalivation occurs in up to 54% of patients receiving clozapine. An evaluation of studies and case reports focusing on management of clozapine-induced hypersalivation was conducted.

CONCLUSIONS

It is unclear whether clozapine increases salivation through its muscarinic M4 receptor activation and/or blockade of alpha2-adrenoceptors, or by causing a distortion in swallowing reflex. Treatment options include chewing gum, reducing the dosage of clozapine, or prescribing pharmacologic agents such as anticholinergics or alpha2-adrenoceptor agonists.