Effects of cevimeline on salivation and thirst in conscious rats

The dosage-dependent effects of cevimeline in preventing olanzapine-induced metabolic side-effects in female rats

Olanzapine has been used for the treatment of schizophrenia and other mental disorders. However, it is associated with serious weight gain and other metabolic side-effects. The antagonistic affinity of olanzapine to muscarinic M3 receptors has been evidenced as one of the main contributors for its weight gain and other metabolic side-effects. Therefore, this study investigated whether the co-treatment of cevimeline (a M3 receptor agonist) could prevent the metabolic side-effects associated with olanzapine medication. Female Sprague Dawley rats were treated orally with olanzapine (2 mg/kg, t.i.d.) and/or cevimeline at 3 dosages (3, 6, 9 mg/kg, t.i.d.), or vehicle for two weeks. Weight gain and food/water intake were measured throughout the drug treatment period. Intraperitoneal glucose tolerance tests and open field tests were conducted. Olanzapine-treated rats demonstrated significantly elevated body weight gain, food intake, feeding efficiency, total white fat mass, liver mass, and plasma triglyceride levels, which could be partly reversed by the co-treatment with cevimeline in a dosage-dependent manner. In general, the body weight gain can only be reversed by the co-treatment of 9 mg/kg cevimeline. The cevimeline co-treatment decreased plasma triglyceride and glucose levels compared with olanzapine only treatment. The results suggested a dosage-dependent effect of cevimeline in ameliorating olanzapine-induced weight gain and metabolic side-effects, which supports further clinical trials using cevimeline to control weight gain and metabolic side-effects caused by antipsychotic medications.

Meta-analysis: Risk of dry mouth with second generation antidepressants

OBJECTIVE

The goal of this meta-analysis was to quantify the risk of dry mouth associated with commonly prescribed antidepressant agents and examine the potential implications of medication class, dose, and pharmacodynamics and dose on risk of treatment-induced dry mouth.

DATA SOURCES AND STUDY SELECTION

A PubMed search was conducted to identify double-blind, randomized, placebo-controlled trials examining the efficacy and tolerability of second generation antidepressant medications for adults with depressive disorders, anxiety disorders, and OCD.

DATA EXTRACTION

A random-effects meta-analysis was used to quantify the pooled risk ratio of treatment-emergent dry mouth with second generation antidepressants compared to placebo. Stratified subgroup analysis and meta-regression was utilized to further examine the effects antidepressant agent, class, dosage, indication, and receptor affinity profile on the measured risk of dry mouth.

RESULTS

99 trials involving 20,868 adults. SNRIs (Relative Risk (RR)=2.24, 95% Confidence Interval (CI): 1.95-2.58, z=11.2, p<0.001) were associated with a significantly greater risk of dry mouth (test for subgroup differences χ²=7.6, df=1; p=0.006) compared to placebo than SSRIs (RR=1.65, 95% CI: 1.39-1.95, z=5.8, p<0.001). There was a significant difference found in the risk of dry mouth between diagnostic indications within the SNRI class (test for subgroup differences χ²=9.63, df=1; p=0.002). Anxiety diagnoses (RR=2.78, 95% CI: 2.29-3.38, z=10.32, p<0.001) were associated with a greater risk of dry mouth compared to depression (RR=1.80, 95% CI: 1.48-2.18, z=5.85, p<0.001). Decreased affinity for Alpha-1 (PE=0.18, 95% CI: 0.07-0.28, z=3.26, p=0.001) and Alpha-2 (PE=0.49, 95% CI: 0.22-0.75, z=3.64, p<0.001) receptors and SERT (PE=0.07, 95% CI: 0.01-0.14, z=2.10, p<0.05) was significantly associated with increased risk of dry mouth.

CONCLUSIONS

The current meta-analysis suggests that SSRIs, SNRIs, and atypical antidepressants are all associated with varying degrees of increased risk of dry mouth. SNRIs were associated with a significantly greater risk of dry mouth compared to SSRIs.

Cevimeline

Cevimeline is an orally administered muscarinic receptor agonist that is indicated for the treatment of symptoms of dry mouth in patients with Sjogren's syndrome. Several well designed placebo-controlled trials demonstrated that 4-12 weeks' therapy with cevimeline 30 mg three times daily improved symptoms of dry mouth in patients with Sjogren's syndrome. Other symptoms, such as dry eye symptoms and overall dryness, also improved to a significantly greater extent with cevimeline than with placebo. Moreover, cevimeline significantly improved the salivary flow rate in patients with Sjogren's syndrome. Increased salivary flow was maintained in the longer term with cevimeline in patients with Sjogren's syndrome and symptoms of dry mouth, according to the results of an open-label 52-week study. From week 20 onwards, rates of patient and investigator satisfaction with the cevimeline dosage were > or =88%. Oral cevimeline 30 mg three times daily was generally well tolerated in patients with Sjogren's syndrome, with many of the most commonly reported adverse events reflecting the pharmacological action of the drug.