Betahistine: a retrospective synopsis of safety data

Betahistine mesylate reduces the damage of blue light exposure in Drosophila model

Previous studies have demonstrated the efficacy of betahistine mesylate in treating vertigo and angioneurotic headache, enhancing microcirculation, and facilitating histamine release. However, limited research has been conducted on the drug's potential in mitigating blue light-induced damage. Thus, this study utilized Drosophila as the model organism and employed the Siler model to investigate the impact of various concentrations of betahistine mesylate on the lifespan, under 3000 lx blue light irradiation. At the same time we measure food intake, spontaneous activity, and sleep duration of Drosophila. The findings of this study indicate that a high concentration of betahistine mesylate can decrease the initial mortality (b0) in male flies, mitigating the damage of blue light to Drosophila. Consequently, this delays the aging process in male Drosophila and extends their average lifespan. After betahistine mesylate ingestion, locomotor activity upon blue light exposure decreased significantly in male Drosophila. In conclusion, this study offers initial evidence supporting the investigation of the regulatory mechanisms of betahistine mesylate on lifespan and its potential anti-blue light effects.

Discovery of the novel and potent histamine H1 receptor antagonists for treatment of allergic diseases

Desloratadine, a second-generation histamine H1 receptor antagonist, has established itself as a first-line drug for the treatment of allergic diseases. Despite its effectiveness, desloratadine exhibits an antagonistic effect on muscarinic M3 receptor, which can cause side effects such as dry mouth and urinary retention, ultimately limiting its clinical application. Herein, we describe the discovery of compound Ⅲ-4, a novel H1 receptor antagonist with significant H1 receptor antagonistic activity (IC50 = 24.12 nM) and enhanced selectivity towards peripheral H1 receptor. In particular, Ⅲ-4 exhibits reduced M3 receptor inhibitory potency (IC50 > 10,000 nM) and acceptable hERG inhibitory activity (17.6 ± 2.1 μM) compare with desloratadine. Additionally, Ⅲ-4 exhibits favorable pharmacokinetic properties, as well as in vivo efficacy and safety profiles. All of these reveal that Ⅲ-4 has potential to emerge as a novel H1 receptor antagonist for the treatment of allergic diseases. More importantly, the compound Ⅲ-4 (HY-078020) has recently been granted clinical approval.

Histaminergic System and Vestibular Function in Normal and Pathological Conditions

Most neurotransmitter systems are represented in the central and peripheral vestibular system and are thereby involved both in normal vestibular signal processing and the pathophysiology of vestibular disorders. However, there is a special relationship between the vestibular system and the histaminergic system. The purpose of this review is to document how the histaminergic system interferes with normal and pathological vestibular function. In particular, we will discuss neurobiological mechanisms such as neuroinflammation that involve histamine to modulate and allow restoration of balance function in the situation of a vestibular insult. These adaptive mechanisms represent targets of histaminergic pharmacological compounds capable of restoring vestibular function in pathological situations. The clinical use of drugs targeting the histaminergic system in various vestibular disorders is critically discussed.

Examination of betahistine bioavailability in combination with the monoamine oxidase B inhibitor, selegiline, in humans-a non-randomized, single-sequence, two-period titration, open label single-center phase 1 study (PK-BeST)

Background

Betahistine was registered in Europe in the 1970s and approved in more than 80 countries as a first-line treatment for Menière's disease. It has been administered to more than 150 million patients. However, according to a Cochrane systematic review of betahistine and recent meta-analyses, there is insufficient evidence to say whether betahistine has any effect in the currently approved dosages of up to 48 mg/d. A combination with the monoamine oxidase B (MAO-B) inhibitor, selegiline, may increase the bioavailability of betahistine to levels similar to the well-established combination of L-DOPA with carbidopa or benserazide in the treatment of Parkinson's disease. We investigated the effect of selegiline on betahistine pharmacokinetics and the safety of the combination in humans.

Methods

In an investigator-initiated prospective, non-randomized, single-sequence, two-period titration, open label single-center phase 1 study, 15 healthy volunteers received three single oral dosages of betahistine (24, 48, and 96 mg in this sequence with at least 2 days' washout period) without and with selegiline (5 mg/d with a loading period of 7 days). Betahistine serum concentrations were measured over a period of 240 min at eight time points (area under the curve, AUC0-240 min). This trial is registered with EudraCT (2019-002610-39) and ClinicalTrials.gov.

Findings

In all three single betahistine dosages, selegiline increased the betahistine bioavailability about 80- to 100-fold. For instance, the mean (±SD) of the area under curve for betahistine 48 mg alone was 0.64 (+/-0.47) h*ng/mL and for betahistine plus selegiline 53.28 (+/-37.49) h*ng/mL. The half-life time of around 30 min was largely unaffected, except for the 24 mg betahistine dosage. In total, 14 mild adverse events were documented.

Interpretation

This phase 1 trial shows that the MAO-B inhibitor selegiline increases betahistine bioavailability by a factor of about 80 to 100. No safety concerns were detected. Whether the increased bioavailability has an impact on the preventive treatment of Menière's disease, acute vestibular syndrome, or post-BPPV residual dizziness has to be evaluated in placebo-controlled trials.

Clinical trial registration

https://clinicaltrials.gov/study/NCT05938517?intr=betahistine%20and%20selegiline&rank=1, identifier: NCT05938517.

Betahistine Prescribing Practices in England: An Analysis of Prescribing and National Spending Pre- and Post-BEMED Trial

OBJECTIVE

Betahistine has not been proven to be superior to placebo in the BEMED study, a multicenter, double-blind, randomized, placebo controlled trial. Our study aimed to establish the prescribing practices of clinicians in England in relation to betahistine and to assess if there has been any change in prescribing practices since the publication of the BEMED trial.

STUDY DESIGN

Retrospective study and clinician survey.

PATIENTS

All patients who were prescribed betahistine from primary care.

MAIN OUTCOME MEASURE

Total quantity of betahistine prescribed and total actual cost.

RESULTS

The average total monthly quantity prescribed was 11,143,253 tablets (range, 10,056,516-12,276,423). Prescribing did not decrease from the period before (January 2014-February 2016) to after (February 2016-February 2021) the publication of the BEMED trial, with the average monthly prescribing before publication being 11,294,848 tablets (range, 10,280,942- 12,276,423) and the average monthly prescribing after publication being 11,081,123 tablets (range, 10,056,516-11,915,707). The average actual monthly cost increased from the period before publication to after publication from a sum of £279,264.82 to a sum of £428,846.22. Most (90.5%) of the survey respondents prescribed betahistine for Menière's disease. Less than half (38.09%) prescribed betahistine for indications other than Menière's disease. Only 45.24% of the clinicians were aware of the results of the BEMED trial.

CONCLUSIONS

Knowledge of the BEMED trial among otology and neurotology subspecialists is lacking. The results of the BEMED have made no difference to prescribing practice, and in fact, the cost of the medication to the health bill has increased.

A comparative study of vestibular improvement and gastrointestinal effect of betahistine and gastrodin in mice

Betahistine and gastrodin are the first-line medications for vestibular disorders in clinical practice, nevertheless, their amelioration effects on vestibular dysfunctions still lack direct comparison and their unexpected extra-vestibular effects remain elusive. Recent clinical studies have indicated that both of them may have effects on the gastrointestinal (GI) tract. Therefore, we purposed to systematically compare both vestibular and GI effects induced by betahistine and gastrodin and tried to elucidate the mechanisms underlying their GI effects. Our results showed that betahistine and gastrodin indeed had similar therapeutic effects on vestibular-associated motor dysfunction induced by unilateral labyrinthectomy. However, betahistine reduced total GI motility with gastric hypomotility and colonic hypermotility, whereas gastrodin did not influence total GI motility with only slight colonic hypermotility. In addition, betahistine, at normal dosages, induced a slight injury of gastric mucosa. These GI effects may be due to the different effects of betahistine and gastrodin on substance P and vasoactive intestinal peptide secretion in stomach and/or colon, and agonistic/anatgonistic effects of betahistine on histamine H1 and H3 receptors expressed in GI mucosal cells and H3 receptors distributed on nerves within the myenteric and submucosal plexuses. Furthermore, treatment of betahistine and gastrodin had potential effects on gut microbiota composition, which could lead to changes in host-microbiota homeostasis in turn. These results demonstrate that gastrodin has a consistent improvement effect on vestibular functions compared with betahistine but less effect on GI functions and gut microbiota, suggesting that gastrodin may be more suitable for vestibular disease patients with GI dysfunction.

Effects of Betahistine on Vestibulo-Ocular Reflex in Normal Healthy Adults: A Randomized Double-Blind, Placebo-Controlled Trial

Introduction

Vertigo, or the perception of a spinning sensation, is a common symptom experienced by patients who are referred to Otorhinolaryngology clinics. Betahistine is a medication that has been widely used to treat vertigo and its accompanying symptoms. However, the effects of this medication on the vestibulo-ocular reflex (VOR) are still unknown. Initially, it was assumed that betahistine should be discontinued prior to any vestibular tests, particularly the video head impulse test (vHIT).

Method

Thirty young healthy adults were randomly divided into two equal groups for this randomized double-blind clinical study (betahistine 24 mg and placebo). Baseline pure-tone audiometry (PTA), tympanometry, and VOR measurements were taken, followed by experimental measurements at one hour, four hours, eight hours, and 24 hours after consumption. The video head impulse test (vHIT) was used to determine the VOR.

Result

Betahistine had no statistically significant effect on vestibulo-ocular reflex gain (F(4,140) = 0.601, p = 0.662). The gain variability across repetitive head impulses remained constant over time.

Conclusions

Betahistine has no effect on the vestibulo-ocular reflex. As a result, this medication can be taken prior to the vHIT procedure.

Low Dose Betahistine in Combination With Selegiline Increases Cochlear Blood Flow in Guinea Pigs

OBJECTIVE

Betahistine is frequently used in the pharmacotherapy for Menière's Disease (MD). Little is known about its mode of action and prescribed dosages vary. While betahistine had an increasing effect on cochlear microcirculation in earlier studies, low dose betahistine of 0.01 mg/kg bw or less was not able to effect this. Selegiline inhibits monoaminooxidase B and therefore potentially the breakdown of betahistine. The goal of this study was to examine whether the addition of selegiline to low dose betahistine leads to increased cochlear blood flow.

METHODS

Twelve Dunkin-Hartley guinea pigs were anesthetized, the cochlea was exposed and a window opened to the stria vascularis. Blood plasma was visualized by injecting fluoresceinisothiocyanate-dextrane and vessel diameter and erythrocyte velocity were evaluated over 20 minutes. One group received low dose betahistine (0.01 mg/kg bw) and selegiline (1 mg/kg bw) i.v. while the other group received only selegiline (1 mg/kg bw) and saline (0.9% NaCl) as placebo i.v.

RESULTS

Cochlear microcirculation increased significantly (P < .001) in guinea pigs treated with low dose betahistine combined with selegiline by up to 58.3 ± 38.7% above baseline over a period of up to 11 minutes. In one guinea pig, the increase was 104.6%. Treatment with Selegiline alone did not affect microcirculation significantly.

CONCLUSIONS

Low dose betahistine increased cochlear microcirculation significantly when combined with selegiline. This should be investigated in further studies regarding dose-effect relation in comparison to betahistine alone. Side effects, in particular regarding circulation, should be considered carefully in view of the clinical applicability of a combination therapy in patients with MD.

Pharmacokinetic Modeling of [11C]GSK-189254, PET Tracer Targeting H3 Receptors, in Rat Brain

The histamine H3 receptor has been considered as a target for the treatment of various central nervous system diseases. Positron emission tomography (PET) studies with the radiolabeled potent and selective histamine H3 receptor antagonist [11C]GSK-189254 in rodents could be used to examine the mechanisms of action of novel therapeutic drugs or to assess changes of regional H3 receptor density in animal models of neurodegenerative disease. [11C]GSK-189254 was intravenously administered to healthy Wistar rats (n = 10), and a 60 min dynamic PET scan was carried out. Arterial blood samples were obtained during the scan to generate a metabolite-corrected plasma input function. PET data were analyzed using a one-tissue compartment model (1T2k), irreversible (2T3k) or reversible two-tissue compartment models (2T4k), graphical analysis (Logan and Patlak), reference tissue models (SRTM and SRTM2), and standard uptake values (SUVs). The Akaike information criterion and the standard error of the estimated parameters were used to select the most optimal quantification method. This study demonstrated that the 2T4k model with a fixed blood volume fraction and Logan graphical analysis can best describe the kinetics of [11C]GSK-189254 in the rat brain. SUV40-60 and the reference tissue-based measurements DVR(2T4k), BPND(SRTM), and SUV ratio could also be used as a simplified method to estimate H3 receptor availability in case blood sampling is not feasible.

High-Dose Betahistine Improves Cognitive Function in Patients With Schizophrenia: A Randomized Double-Blind Placebo-Controlled Trial

Background: There is currently no effective treatment for cognitive impairment associated with schizophrenia (CIAS). Recent studies have shown that increased histamine levels in the brain may help to improve CIAS symptoms. Betahistine is an H1-receptor agonist and H3-receptor antagonist. This study evaluated the effect of high-dose betahistine on cognitive function as well as its safety in Chinese Han patients with schizophrenia. Methods: This randomized double-blind, placebo-controlled trial enrolled 89 patients with schizophrenia who were randomly administered betahistine (72 mg/d) or placebo for 12 weeks. At baseline and at 4, 8, and 12 weeks after commencing the intervention, we measured changes in cognitive function and clinical symptoms using the MATRICS Consensus Cognitive Battery (MCCB) and Positive and Negative Syndrome Scale (PANSS), respectively. Furthermore, we used the Treatment Emergent Symptom Scale (TESS) to assess the adverse effects of the patients' medications. Results: Compared to the placebo group, the betahistine group showed significant improvements in the MCCB composite score after 12 weeks of treatment (p = 0.003) as well as improvements in MCCB verbal learning (p = 0.02) and visual learning (p = 0.001) domain scores. However, there were no significant improvements in the PANSS total scores or subscores (p > 0.05). Generally, high-dose betahistine treatment was considered safe in patients with schizophrenia. Conclusions: Additional use of high-dose betahistine can effectively improve cognitive function but not psychiatric symptoms in patients with schizophrenia. Betahistine (72 mg/d) is well tolerated by Chinese Han patients with schizophrenia. Trial Registration: chictr.org.cn, identifier: ChiCTR1900021078. http://www.chictr.org.cn/edit.aspx?pid=35484&htm=4.

Association Between Asthma and Meniere's Disease: A Nested Case-Control Study

OBJECTIVES/HYPOTHESIS

This study aimed to investigate the association between Meniere's disease and prior history of asthma.

STUDY DESIGN

A nested case-control study.

METHODS

Among the patients aged ≥40 years from the Korean National Health Insurance Service-Health Screening Cohort 2002-2015, 7,734 diagnosed with Meniere's disease between 2004 and 2015 were enrolled in this study. From the 505,834 participants without a prior history of Meniere's disease, 30,936 control participants were selected based on age, sex, income, and region of residence. The presence of a prior history of asthma before the diagnosis of Meniere's disease was compared between the Meniere's disease group and control group using conditional logistic regression with odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS

Prior history of asthma was associated with 1.30 (1.21-1.39) times higher odds of Meniere's disease (E-value = 1.92 [1.71]). Both allergic asthma and nonallergic asthma patients demonstrated higher odds of Meniere's disease than the control group (adjusted OR = 1.21 [1.08-1.36] and E-value = 1.72 [1.37] for allergic asthma; adjusted OR = 1.26 [1.17-1.36] and E-value = 1.83 [1.60] for nonallergic asthma).

CONCLUSIONS

This study is the first to demonstrate a positive relationship between Meniere's disease and prior asthma history in adults. The association between prior asthma history and Meniere's disease was noted in both allergic and nonallergic asthma cases. The potential development of Meniere's disease should be considered when managing the asthma patients with dizziness or vertigo.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Targeting Histamine and Histamine Receptors for the Precise Regulation of Feeding

Histamine has long been accepted as an anorexigenic agent. However, lines of evidence have suggested that the roles of histamine in feeding behaviors are much more complex than previously thought, being involved in satiety, satiation, feeding motivation, feeding circadian rhythm, and taste perception and memory. The functional diversity of histamine makes it a viable target for clinical management of obesity and other feeding-related disorders. Here, we update the current knowledge about the functions of histamine in feeding and summarize the underlying molecular and neural circuit mechanisms. Finally, we review the main clinical studies about the impacts of histamine-related compounds on weight control and discuss insights into future research on the roles of histamine in feeding. Despite the recent progress in histamine research, the histaminergic feeding circuits are poorly understood, and it is also worth verifying the functions of histamine receptors in a more spatiotemporally specific manner.

Development, Implementation, Evaluation, and Long-Term Outcome of a Program to Increase Student Interest in Anesthesia and Intensive Care Training

OBJECTIVES

The increasing need for anesthetists has been coupled with a rising number of open training positions. Thus, there is an increased need to attract future anesthetists among students and graduates from medical universities. Using results from a questionnaire, we designed an information and training program to increase interest in anesthesia and intensive care.

MATERIALS AND METHODS

With the use of semistructured interviews, medical students were questioned about factors influencing their decision for a speciality. We used the results to design an information and practice program for students and young doctors. This program was held 12 times at different anesthesia departments in different hospitals. Evaluation was obtained through a feedback questionnaire at the end of each sessions and with another questionnaire 2 to 4 years after the program.

RESULTS

Feedback showed positive responses concerning utility for practical work, actuality, and relevance for daily practical work. There was a 22.7% response from participants for the follow-up questionnaire. Of these, 87% stated that interest in anesthesia was increased by the program, and 74% underwent practical training in an anesthesia department. Seventeen participants started a speciality training for anesthesia and intensive care medicine.

CONCLUSIONS

The design of this practice-oriented program was effective in eliciting, spreading, and increasing interest and attracting students to a medical specialty.

Betahistine in Ménière's Disease or Syndrome: A Systematic Review

BACKGROUND

Ménière's disease is characterized by recurrent episodes of vertigo, hearing loss, and tinnitus, often with a feeling of fullness in the ear. Although betahistine is thought to be specifically effective for Ménière's disease, no evidence for a benefit from the use of betahistine exists, despite its widespread use. Reassessment of the effect of betahistine for Ménière's disease is now warranted.

SEARCH METHODS

We searched for randomized controlled trials (RCTs) in the Central Register of Controlled Trials (CENTRAL), Ovid Medline, Ovid Embase, CINAHL, Web of Science, Clinicaltrials.gov, ICTRP, and additional sources for published and unpublished trials, in which betahistine was compared to placebo.

DATA COLLECTION AND ANALYSIS

Our outcomes involved vertigo, significant adverse effect (upper gastrointestinal discomfort), hearing loss, tinnitus, aural fullness, other adverse effects, and disease-specific health-related quality of life. We used GRADE to assess the quality of the evidence.

MAIN RESULTS

We included 10 studies: 5 studies used a crossover design and the remaining 5 were parallel-group RCTs. One study with a low risk of bias found no significant difference between the betahistine groups and placebo with respect to vertigo after a long-term follow-up period. No significant difference in the incidence of upper gastrointestinal discomfort was found in 2 studies (low-certainty evidence). No differences in hearing loss, tinnitus, or well-being and disease-specific health-related quality of life were found (low- to very low-certainty of evidence). Data on aural fullness could not be extracted. No significant difference between the betahistine and the placebo groups (low-certainty evidence) could be demonstrated in the other adverse effect outcome with respect to dull headache. The pooled risk ratio for other adverse effect in the long term demonstrated a lower risk in favor of placebo over betahistine.

CONCLUSIONS

High-quality studies evaluating the effect of betahistine on patients with Ménière's disease are lacking. However, one study with low risk of bias found no evidence of a difference in the effect of betahistine on the primary outcome, vertigo, in patients with Ménière's disease when compared to placebo. The main focus of future research should be on the use of comparable outcome measures by means of patient-reported outcome measures.

In Vitro Physiological Effects of Betahistine on Cell Lines of Various Origins

Objectives

Betahistine is a histamine analog commonly prescribed for symptomatic treatment of vertiginous symptoms. In vitro studies have shown that betahistine was not toxic at the prescribed doses in a nasal epithelial cell line. However, the effect of betahistine on other cell types has not been studied. In this study, we aimed to investigate some of the physiological effects of betahistine on L929 fibroblast, A549 lung cancer, human umbilical vein endothelial (HUVEC), and Ishikawa endometrial cell lines.

Materials and Methods

Cellular proliferation was assed assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, apoptosis was evaluated by acridine orange-ethidium bromide staining, and cellular migration was assed assessed by scratch assay.

Results

Betahistine treatment (0.1-0.5 mg/mL, 24 hours) can inhibit cell proliferation and induce apoptosis in HUVEC, A549, Ishikawa, and L929 cell lines. Betahistine (≥0.1 mg/mL) significantly increased the number of apoptotic cells (HUVEC: 26.3%, A549: 17.3%, L929: 8.6%, and Ishikawa: 2.3%). Betahistine at doses over 0.1 mg/mL significantly suppressed the cell migration rate in all of the cell lines. In contrast, exposure to a low dose of betahistine (0.025 mg/mL) induced migration rates of HUVEC and Ishikawa cells by 81% and 48%, respectively.

Conclusion

Betahistine may alter the processes of cellular proliferation, apoptosis, and cellular migration in a cell line- and dose-dependent manner. In this sense, proliferative and metastatic properties of certain cancer cells can potentially be altered in response to betahistine treatment.

Betahistine add-on therapy for treatment of subjects with posterior benign paroxysmal positional vertigo: a randomized controlled trial

Introduction

Benign paroxysmal positional vertigo is a common vestibular disorder that accounts for one fifth of hospital admissions due to vertigo, although it is commonly undiagnosed.

Objective

To evaluate the effects of betahistine add-on therapy in the treatment of subjects with posterior benign paroxysmal positional vertigo.

Methods

This randomized controlled study was conducted in a population of 100 subjects with posterior benign paroxysmal positional vertigo. Subjects were divided into the Epley maneuver + betahistine group (group A) and Epley maneuver only (group B) group. Subjects were evaluated before and 1-week after the maneuver using a visual analog scale and dizziness handicap inventory

Results

One hundred subjects completed the study protocol. The Epley maneuver had an overall success rate of 95% (96% in group A; 94% in group B, p =  0.024). Groups A and B had similar baseline visual analog scale scores (6.98 ± 2.133 and 6.27 ± 2.148, respectively, p = 0.100). After treatment, the visual analog scale score was significantly lower in both groups, and was significantly lower in group A than group B (0.74 ± 0.853 vs. 1.92 ± 1.288, respectively, p = 0.000). The change in visual analog scale score after treatment compared to baseline was also significantly greater in group A than group B (6.24 ± 2.01 vs. 4.34 ± 2.32, respectively, p = 0.000). The baseline dizziness handicap inventory values were also similar in groups A and B (55.60 ± 22.732 vs. 45.59 ± 17.049, respectively, p = 0.028). After treatment, they were significantly lower in both groups. The change in score after treatment compared to baseline was also significantly greater in group A than group B (52.44 ± 21.42 vs. 35.71 ± 13.51, respectively, p = 0.000).

Conclusion

The Epley maneuver is effective for treatment of benign paroxysmal positional vertigo. Betahistine add-on treatment in posterior benign paroxysmal positional vertigo resulted in improvements in both visual analog scale score and dizziness handicap inventory.

Central Histamine Boosts Perirhinal Cortex Activity and Restores Forgotten Object Memories

BACKGROUND

A method that promotes the retrieval of lost long-term memories has not been well established. Histamine in the central nervous system is implicated in learning and memory, and treatment with antihistamines impairs learning and memory. Because histamine H₃ receptor inverse agonists upregulate histamine release, the inverse agonists may enhance learning and memory. However, whether the inverse agonists promote the retrieval of forgotten long-term memory has not yet been determined.

METHODS

Here, we employed multidisciplinary methods, including mouse behavior, calcium imaging, and chemogenetic manipulation, to examine whether and how the histamine H₃ receptor inverse agonists, thioperamide and betahistine, promote the retrieval of a forgotten long-term object memory in mice. In addition, we conducted a randomized double-blind, placebo-controlled crossover trial in healthy adult participants to investigate whether betahistine treatment promotes memory retrieval in humans.

RESULTS

The treatment of H₃ receptor inverse agonists induced the recall of forgotten memories even 1 week and 1 month after training in mice. The memory recovery was mediated by the disinhibition of histamine release in the perirhinal cortex, which activated the histamine H₂ receptor. Histamine depolarized perirhinal cortex neurons, enhanced their spontaneous activity, and facilitated the reactivation of behaviorally activated neuronal ensembles. A human clinical trial revealed that treatment of H₃ receptor inverse agonists is specifically more effective for items that are more difficult to remember and subjects with poorer performance.

CONCLUSIONS

These results highlight a novel interaction between the central histamine signaling and memory engrams.

H3 antagonists and postoperative cognitive dysfunction

Since histamine (HA) was first synthesized in 1907 and isolated as a bacterial contaminant of an extract of ergot in 1910, its role in health and disease and its molecular mechanism of action have been unraveled, leading to the formulation of an array of drugs with immense therapeutic value. HA is produced by decarboxylation of histidine, and its biological actions are mediated through four HA receptors, namely, H₁, H₂, H₃, and H₄ based on their sequence, their link to differential intracellular signaling mechanisms, and their unique pharmacological properties. H₁ and H₂ receptors have been targeted for treating allergic conditions and peptic ulcers, respectively. The discovery of a third HA receptor subtype (H₃R) by molecular biologists in 1983, structurally a member of the G-protein-coupled receptor family, has led to the development of many potent and selective H₃ receptor antagonists having the potential to treat a wide spectrum of neurological diseases including postoperative cognitive dysfunction.

Betahistine for tinnitus

BACKGROUND

Tinnitus is a symptom defined as the perception of sound in the absence of an external source. In England alone there are an estimated ¾ million general practice consultations every year where the primary complaint is tinnitus, equating to a major burden on healthcare services. Clinical management strategies include education and advice, relaxation therapy, tinnitus retraining therapy, cognitive behavioural therapy, sound enrichment using ear-level sound generators or hearing aids, and drug therapies to manage co-morbid symptoms such as sleep difficulties, anxiety or depression. As yet, no drug has been approved for tinnitus by a regulatory body. Nonetheless, over 100,000 prescriptions for betahistine are being filled every month in England, and nearly 10% of general practitioners prescribe betahistine for tinnitus.

OBJECTIVES

To assess the effects of betahistine in patients with subjective idiopathic tinnitus.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL, via the Cochrane Register of Studies); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 July 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) recruiting patients of any age with acute or chronic subjective idiopathic tinnitus were included. We included studies where the intervention involved betahistine and this was compared to placebo, no intervention or education and information. We included all courses of betahistine, regardless of dose regimens or formulations and for any duration of treatment.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Our primary outcomes included tinnitus loudness and significant adverse effects (upper gastrointestinal discomfort). Our secondary outcomes included tinnitus symptom severity as measured by the global score on a multi-item tinnitus questionnaire, depressive symptoms, symptoms of generalised anxiety, health-related quality of life, other adverse effects (e.g. headache, drowsiness, allergic skin reactions (pruritis, rashes) and exacerbation of tinnitus) and tinnitus intrusiveness. We used GRADE to assess the quality of evidence for each outcome; this is indicated in italics.

MAIN RESULTS

This review included five studies (with a total of 303 to 305 participants) comparing the effects of betahistine with placebo in adults with subjective idiopathic tinnitus. Four studies were parallel-group RCTs and one had a cross-over design. The risk of bias was unclear in all of the included studies.Due to heterogeneity in the outcomes measured and measurement methods used, very limited data pooling was possible. When we pooled the data from two studies for the primary outcome tinnitus loudness, the mean difference on a 0- to 10-point visual analogue scale at one-month follow-up was not significant between betahistine and placebo (-0.16, 95% confidence interval (CI) -1.01 to 0.70; 81 participants) (very low-quality evidence). There were no reports of upper gastrointestinal discomfort (significant adverse effect) in any study.As a secondary outcome, one study found no difference in the change in the Tinnitus Severity Index between betahistine and placebo (mean difference at 12 weeks 0.02, 95% CI -1.05 to 1.09; 50 participants) (moderate-quality evidence). None of the studies reported the other secondary outcomes of changes in depressive symptoms or depression, anxiety symptoms or generalised anxiety, or health-related quality of life as measured by a validated instrument, nor tinnitus intrusiveness.Other adverse effects that were reported were not treatment-related.

AUTHORS' CONCLUSIONS

There is an absence of evidence to suggest that betahistine has an effect on subjective idiopathic tinnitus when compared to placebo. The evidence suggests that betahistine is generally well tolerated with a similar risk of adverse effects to placebo treatments. The quality of evidence for the reported outcomes, using GRADE, ranged from moderate to very low.If future research into the effectiveness of betahistine in patients with tinnitus is felt to be warranted, it should use rigorous methodology. Randomisation and blinding should be of the highest quality, given the subjective nature of tinnitus and the strong likelihood of a placebo response. The CONSORT statement should be used in the design and reporting of future studies. We also recommend the development of validated, patient-centred outcome measures for research in the field of tinnitus.

Betahistine effects on weight-related measures in patients treated with antipsychotic medications: a double-blind placebo-controlled study

RATIONALE

Weight gain during treatment with antipsychotics is a prominent side-effect, especially with some second-generation antipsychotics, such as olanzapine and clozapine, and pharmacological treatments which ameliorate this side-effect are important to investigate. Decreases in histaminergic transmission in the brain induced by antipsychotics may be one of the mechanisms contributing to weight gain. Since betahistine is a histaminergic agonist, it may potentially counteract the weight gain effects of antipsychotics.

METHOD

We conducted a double-blind placebo-controlled study to evaluate the effects of 12 weeks of treatment with betahistine (N = 29) or placebo (N = 22) in adolescents and adults on anthropomorphically measured weight-related parameters, appetite, and fasting glucose-lipid and leptin levels in 51 patients treated with first and/or second-generation antipsychotics who had gained weight during treatment or had high body-mass-index (BMI). Psychopathology and side-effects were also assessed with relevant scales.

RESULTS

In a sub-group of patients being treated with olanzapine or clozapine (n = 26), betahistine was significantly (P < .05) better than placebo in preventing increases in weight (3.1 kg less weight gain than placebo), BMI, and waist circumference. Betahistine did not decrease weight or BMI in patients treated with other antipsychotics. There was also no effect of betahistine on preventing weight or BMI gain in the total combined sample of all subjects. Betahistine did not significantly improve appetite or glucose-lipid measures in either subgroup. There were no significant differences in side-effects or psychopathology changes in the betahistine- vs. placebo-treated patients.

CONCLUSIONS

These results suggest that betahistine may potentially be a useful adjunctive drug for decreasing weight gain in patients treated with antipsychotics that are potent histamine antagonists, such as olanzapine or clozapine, but may not be useful for this purpose in patients on other antipsychotic medications. The results justify larger placebo-controlled studies to further confirm these effects before specific recommendations can be made for routine use.

Efficacy of betahistine plus cognitive behavioral therapy on residual dizziness after successful canalith repositioning procedure for benign paroxysmal positional vertigo

BACKGROUND

Some patients still complain of residual dizziness after successful canalith repositioning procedure (CRP) for benign paroxysmal positional vertigo (BPPV). Previous study found that compared to the low-dose betahistine, the high-dose betahistine could yield better efficacy in treating residual dizziness. Therefore, this study was conducted to assess whether the addition of cognitive behavioral therapy (CBT) could make low-dose betahistine produce similar results to high-dose betahistine in treating residual dizziness.

METHODS

The recruited patients were randomly assigned to receive either low-dose betahistine (6 mg/time, three times/day) or high-dose betahistine (12 mg/time, three times/day). Patients in the low-dose group also received CBT (twice a week, 1 hour per time). The treatment was continued for 4 weeks. The duration of residual dizziness, 25-item Dizziness Handicap Inventory (DHI), Hamilton Anxiety Rating Scale (HARS), and Hamilton Depression Rating Scale (HDRS) were recorded and analyzed. The duration of residual dizziness and DHI score were the primary outcomes, and the HARS and HDRS scores were the secondary outcomes.

RESULTS

Each group had 50 patients. After treatment, the average DHI scores, HDRS scores, and HARS scores were significantly decreased in both groups. The duration of residual dizziness and average DHI score were nonsignificantly different (P=0.08; P=0.06) between the two groups, although they were lower in the low-dose group. Compared to the high-dose group, the low-dose group had the significantly lower average HDRS score (P=0.007) and HARS score (P=0.02). Meanwhile, four patients in the high-dose group experienced intolerable stomach upset.

CONCLUSION

These results demonstrated that the addition of CBT could make low-dose beta-histine produce similar results to high-dose betahistine in treating residual dizziness. Moreover, the low-dose betahistine plus CBT showed some advantages over high-dose betahistine in relieving depressive and anxiety symptoms and should be further explored.

Betahistine dihydrochloride transdermal delivery via optimized thermosensitive gels: percutaneous absorption evaluation using rat growth as a biomarker

The aim of this study was to develop and optimize a betahistine dihydrochloride (BH) thermoreversible bioadhesive gel intended for transdermal delivery. The gels were obtained via cold method. A full factorial design was employed to investigate the joint effect of Poloxamer 407 concentration (18 and 20%), adhesive polymer type (Polyvinyl pyrolidone, Hydroxypropyl methylcellulose, and Carbopol 934), and adhesive polymer concentration (0.5 and 1.5%) on gelling temperature, viscosity at 37 °C, and adhesion strength. Data collected were analyzed using multiple linear regression. A desirability index approach with relative importance weight was used to choose the most desirable formulation. F4 (20% Poloxamer+1.5% Carbopol) was selected for further characterization. F4 released 96.97% drug in 12 h across hairless rat skin. F4 gelation temperature and time were 36 ± 0.35 °C, and 6 ± 0.7 min, respectively. F4 adhesive force was 8835.68 dyne/cm². F4 was tested for its appetite suppressing effect in a rat model and it was evaluated histopathologically. Rats' chow intake and weight gain was significantly decreased with no signs of inflammation or lipolysis when the optimized BH gel formulation, F4, was compared with untreated animals and animals treated with BH free gel. The results suggest that BH is percutaneously absorbed from the gel base and that the BH gel is tolerable. The desirability index approach with relative importance weight of responses was effective in determination of the optimum formulation. BH is systemically effective and well-tolerated when applied topically in hydrogel-based systems. The Carbopol-Poloxamer gel is a promising modality for transdermal delivery of BH.

Pregnancy outcomes after maternal betahistine exposure: A case series

OBJECTIVE

To investigate the pregnancy outcomes of women who were exposed to betahistine during their pregnancies.

METHODS

We identified and evaluated the outcomes of 27 pregnant women who were referred to Terafar (Teratology Information Service, Izmir, Turkey) for a teratological risk assessment.

RESULTS

Of 24 pregnancies with known outcomes, 21 resulted in live births (including two pairs of twins) whereas two ended with miscarriage and three with elective terminations. Among the 20 live births for whom the malformation details were available, there were 17 normal outcomes, one major and two minor congenital malformations.

CONCLUSIONS

Despite a number of limitations, this case series may be of value regarding counseling pregnant women with inadvertent betahistine exposure. Further epidemiological studies with larger sample sizes and control groups are necessary to draw more definite conclusions.

Treatment of Meniere's disease with intratympanic dexamethazone plus high dosage of betahistine

PURPOSE

The aim of the present study was to assess if the combined therapy of intratympanic dexamethasone (ITD) and high dosage of betahistine (HDBH) is able to provide increased vertigo control compared to ITD alone in patients suffering from definite unilateral Meniere's disease (MD).

MATERIALS AND METHODS

Consecutive MD patients were enrolled and randomly divided in two groups, each comprising 33 cases. Group A received a combination of ITD and identical-appearing placebo pills while Group B received a combination of ITD and HDBH. ITD protocol consisted of three consecutive daily injections. HDBH comprised 144mg/day (48mg tid). The main outcome measures were: 1) vertigo class, pure tone average (PTA), speech discrimination score (SDS) and Functional Level Score (FLS) according to the American Academy of Otolaryngology-Head and Neck Surgery criteria; 2) complete and substantial vertigo control according to the Kaplan-Meier survival method.

RESULTS

Sixty two patients completed the 24-month follow-up. A complete vertigo control was achieved in 14 patients (44%) from Group A and in 22 patients (73.3%) from Group B, statistically significant (p=0.01). Complete vertigo relief is also significant according to the Kaplan-Meier method: p=0.027, log rank test. Substantial vertigo control was obtained in 21 patients (65.6%) in Group A and 27 patients (90%) in Group B. The difference is statistically significant, p=0.02. The difference is significant according to the Kaplan-Meier method: p=0.035, log rank test. No significant differences between hearing levels and tinnitus scores were demonstrated between the groups.

CONCLUSIONS

Our preliminary results demonstrate that complete and substantial vertigo control is significantly higher in patients treated with a combination of HDBH and ITD.

Betahistine decreases olanzapine-induced weight gain and somnolence in humans

Olanzapine's efficacy in schizophrenia is attributed to antagonism of dopamine and serotonin receptors. Olanzapine is also a potent histamine-H1 antagonist that results in weight gain and somnolence. Betahistine is a centrally acting histamine-H1 agonist, and therefore may reduce olanzapine's effect on histamine receptors in the brain. Olanzapine's high affinity for the histamine-H1 receptor warrants the use of high doses of betahistine. Forty-eight healthy women were recruited and randomized to receive either betahistine 144 mg/day or matching placebo for 4 weeks. Due to the high dose of betahistine, olanzapine was started only on the second week and titrated up to 10 mg/day, and co-administration continued for an additional 2 weeks. Only nominal differences in adverse events were noted between the treatment groups. Betahistine caused a 37% reduction in mean weight gain (1.24 kg in the betahistine arm vs. 1.93 kg in the placebo arm; p=.049) and 60% reduction in the mean increase in daytime Epworth sleepiness scores (1.82 units in the betahistine group vs. 3.57 units in the placebo group; p=.042). The present study suggests that betahistine-olanzapine co-administration, in healthy female subjects, yields an acceptable safety profile with mitigation of weight gain and somnolence. This should be further tested in a patient cohort.

It is 2015: What are the best diagnostic and treatment options for Ménière’s disease?

Ménière’s disease (MD) is a common cause of recurrent vertigo. Its pathophysiology is still unclear and controversial. The most common histological finding in postmortem temporal bone studies of patients is endolymphatic hydrops (EH). However, not all cases of hydrops are associated with MD and it may represent the end point of various etiologies. The diagnostic criteria for MD have undergone changes during the past few decades. A recent collaboration among specialty societies in United States, Europe and Japan has given rise to a new set of guidelines for the diagnosis and classification of MD. The aim is to develop international consensus criteria for MD that would help improve the quality of data collected from patients. The diagnosis of MD can be difficult in some cases as there is no gold standard for testing. Previous use of audiometric data and electrocochleography are poorly sensitive as screening tools. Recently magnetic resonance imaging as a diagnostic tool for identifying EH has gained popularity in Asia and Europe. Vestibular evoked myogenic potentials are also used but lack specificity. Finally, the treatment for MD has improved with the introduction of intratympanic treatments with steroids and gentamicin as well as less invasive treatment with the Meniett device.

Menière's disease

Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.

The histaminergic system as a target for the prevention of obesity and metabolic syndrome

The control of food intake and body weight is very complex. Key factors driving eating behavior are hunger and satiety that are controlled by an interplay of several central and peripheral neuroendocrine systems, environmental factors, the behavioral state and circadian rhythm, which all concur to alter homeostatic aspects of appetite and energy expenditure. Brain histamine plays a fundamental role in eating behavior as it induces loss of appetite and has long been considered a satiety signal that is released during food intake (Sakata et al., 1997). Animal studies have shown that brain histamine is released during the appetitive phase to provide a high level of arousal preparatory to feeding, but also mediates satiety. Furthermore, histamine regulates peripheral mechanisms such as glucose uptake and insulin function. Preclinical research indicates that activation of H1 and H3 receptors is crucial for the regulation of the diurnal rhythm of food consumption; furthermore, these receptors have been specifically recognized as mediators of energy intake and expenditure. Despite encouraging preclinical data, though, no brain penetrating H1 receptor agonists have been identified that would have anti-obesity effects. The potential role of the H3 receptor as a target of anti-obesity therapeutics was explored in clinical trials that did not meet up to the expectations or were interrupted (clinicaltrials.gov). Nonetheless, interesting results are emerging from clinical trials that evaluated the attenuating effect of betahistine (an H1 agonist/H3 antagonist) on metabolic side effects associated with chronic antipsychotics treatment. Aim of this review is to summarize recent results that suggest the clinical relevance of the histaminergic system for the treatment of feeding disorders and provide an up-to-date summary of preclinical research. This article is part of the Special Issue entitled 'Histamine Receptors'.

Intratympanic dexamethasone versus high dosage of betahistine in the treatment of intractable unilateral Meniere disease

PURPOSE

The objective of our randomized, double-blind study was to compare the effectiveness of intratympanic (IT) dexamethasone versus high-dosage of betahistine in the treatment of patients with intractable unilateral Meniere disease (MD).

MATERIALS AND METHODS

Sixty six patients with definite unilateral MD were randomly divided in two groups: Group A received a combination of IT dexamethasone (DX) and identical-appearing placebo pills while Group B received a combination of high-dosage betahistine and IT saline. Intratympanic injections were repeated for three times with an interlude of 3days. High-dosage of betahistine entailed 144mg/day. Mean outcome measures consisted of vertigo control, pure tone average (PTA), speech discrimination score, Functional Level Score, Dizziness Handicap Inventory and Tinnitus Handicap Inventory.

RESULTS

Fifty nine patients completed the study and were available at 12months for analysis. In Group A complete vertigo control (class A) was attained in 14 patients (46.6%) and substantial control (class B) in 7 patients (20%). In Group B, 12 patients (41%) achieved complete vertigo control (class A), 5 patients (17%) substantial control (class B). There is no statistical difference in vertigo control between the two treatment groups. In Group A hearing was unchanged in 14 patients and improved in 4 patients, while in Group B hearing was unchanged in 16 patients and improved in 2 patients.

CONCLUSIONS

Our preliminary results demonstrate that high-dosage of betahistine achieved similar outcomes as IT dexamethasone in the control of vertigo and hearing preservation.

Effects and safety profile of betahistine in patients in the Russian contingent of OSVaLD, an open-label observational study in vestibular vertigo

BACKGROUND

We report here data from the >200 patients recruited in Russia to take part in OSVaLD, a 12-week, open-label, post-marketing surveillance study of the response to betahistine 48 mg/day in vertigo of peripheral vestibular origin carried out in a total of 13 countries.

METHODS

The primary efficacy endpoint was change in the Dizziness Handicap Inventory (DHI; 100-point scale). Changes in Hospital Anxiety and Depression Scale (HADS) and Medical Outcomes Study Short-Form 36, version 2 (SF-36v2(®)) scores were a priori secondary Outcomes.

RESULTS

Total DHI score improved by 43 points during betahistine treatment. This aggregate improvement was equally distributed across the three domains of the DHI (physical, emotional, and functional; P<0.0001 for main and subscore changes from baseline). Statistically significant improvements versus baseline were also observed in mean HADS scores for anxiety and depression (both P<0.0001), and in the Physical Component Summary and Mental Component Summary scores of the SF-36v2 (both P<0.0001 versus baseline). Only one suspected adverse drug reaction was recorded in the Russian safety population (n=204), indicating that betahistine was well tolerated in those patients.

CONCLUSION

Betahistine 48 mg/day was associated with clear improvements in well-configured and widely validated measures of health-related quality of life and an encouraging tolerability profile in patients in Russia who took part in OSVaLD.

Effects and tolerability of betahistine in patients with vestibular vertigo: results from the Romanian contingent of the OSVaLD study

Background and methods

An efficacy population of 245 patients with vertigo of peripheral vestibular origin was recruited in Romania as part of a 3-month multinational, post-marketing surveillance study of open-label betahistine 48 mg/day (OSVaLD). Endpoints were changes in the Dizziness Handicap Index (primary endpoint), Medical Outcome Study Short-Form 36 (SF-36v2^®), and the Hospital Anxiety and Depression Scale.

Results

During treatment, the total Dizziness Handicap Index score improved by 41 points (on a 100-point scale). Statistically significant improvements of 12–14 points were recorded in all three domains of the Dizziness Handicap Index scale (P<0.0001). Betahistine therapy was also accompanied by progressive improvements in mean Hospital Anxiety and Depression anxiety and depression scores (P<0.0001) and significant improvements in both the physical and mental component summary of the SF-36v2 (P<0.0001). Betahistine was well tolerated, with only one suspected adverse drug reaction recorded in the Romanian safety population (n=259).

Conclusion

Betahistine 48 mg/day was associated with improvements in multiple measures of health-related quality of life and had a good tolerability profile in these Romanian patients with recurrent peripheral vestibular vertigo.

Betahistine ameliorates olanzapine-induced weight gain through modulation of histaminergic, NPY and AMPK pathways

Olanzapine is widely used to treat schizophrenia and other disorders, but causes adverse obesity and other metabolic side-effects. Both animal and clinical studies have shown that co-treatment with betahistine (a histaminergic H1 receptor agonist and H3 receptor antagonist) is effective for ameliorating olanzapine-induced weight gain/obesity. To reveal the mechanisms underlying these effects, this study investigated the effects of co-treatment of olanzapine and betahistine (O+B) on expressions of histaminergic H1 receptor (H1R), AMP-activated protein kinase (AMPK), neuropeptide Y (NPY), and proopiomelanocortin (POMC) in the hypothalamus associated with reducing olanzapine-induced weight gain. Olanzapine significantly upregulated the mRNA and protein expressions of H1R, while O+B co-treatment significantly downregulated the H1R levels, compared to the olanzapine-only treatment group. The NPY mRNA expression was significantly enhanced by olanzapine, but it was significantly reversed by O+B co-treatment. The hypothalamic H1R expression was positively correlated with total food intake, and NPY expression. Olanzapine also increased AMPKα activation measured by the AMPKα phosphorylation (pAMPKα)/AMPKα ratio compared with controls, whereas O+B co-treatment decreased the pAMPKα/AMPKα ratio, compared with olanzapine only treatment. The pAMPKα/AMPKα ratio was positively correlated with total food intake and H1R expression. Although olanzapine administration decreased the POMC mRNA level, this level was not affected by O+B co-treatment. Therefore, these results suggested that co-treatment with betahistine may reverse olanzapine-induced body weight gain via the H1R-NPY and H1R-pAMPKα pathways.

Preventing olanzapine-induced weight gain using betahistine: a study in a rat model with chronic olanzapine treatment

Olanzapine is the one of first line antipsychotic drug for schizophrenia and other serious mental illness. However, it is associated with troublesome metabolic side-effects, particularly body weight gain and obesity. The antagonistic affinity to histamine H₁ receptors (H₁R) of antipsychotic drugs has been identified as one of the main contributors to weight gain/obesity side-effects. Our previous study showed that a short term (2 weeks) combination treatment of betahistine (an H₁R agonist and H₃R antagonist) and olanzapine (O+B) reduced (−45%) body weight gain induced by olanzapine in drug-naïve rats. A key issue is that clinical patients suffering with schizophrenia, bipolar disease and other mental disorders often face chronic, even life-time, antipsychotic treatment, in which they have often had previous antipsychotic exposure. Therefore, we investigated the effects of chronic O+B co-treatment in controlling body weight in female rats with chronic and repeated exposure of olanzapine. The results showed that co-administration of olanzapine (3 mg/kg, t.i.d.) and betahistine (9.6 mg/kg, t.i.d.) significantly reduced (−51.4%) weight gain induced by olanzapine. Co-treatment of O+B also led to a decrease in feeding efficiency, liver and fat mass. Consistently, the olanzapine-only treatment increased hypothalamic H₁R protein levels, as well as hypothalamic pAMPKα, AMPKα and NPY protein levels, while reducing the hypothalamic POMC, and UCP₁ and PGC-1α protein levels in brown adipose tissue (BAT). The olanzapine induced changes in hypothalamic H₁R, pAMPKα, BAT UCP₁ and PGC-1α could be reversed by co-treatment of O+B. These results supported further clinical trials to test the effectiveness of co-treatment of O+B for controlling weight gain/obesity side-effects in schizophrenia with chronic antipsychotic treatment.

Modifications of histamine receptor signaling affect bone mechanical properties in rats

Histamine receptors are expressed on bone cells and histamine may be involved in regulation of bone metabolism. The aim of the present study was to investigate the effects of loratadine (an H(1) receptor antagonist), ranitidine (an H(2) receptor antagonist) and betahistine (an H(3) receptor antagonist and H(1) receptor agonist) on bone mechanical properties in rats. Loratadine (5 mg/kg/day, po), ranitidine (50 mg/kg/day, po), or betahistine dihydrochloride (5 mg/kg/day, po), were administered for 4 weeks to non-ovariectomized and bilaterally ovariectomized (estrogen-deficient) 3-month-old rats, and their effects were compared with appropriate controls. Serum levels of bone turnover markers, bone mineralization and mechanical properties of the proximal tibial metaphysis, femoral diaphysis and femoral neck were studied. In rats with normal estrogen level, administration of loratadine slightly favorably affected mechanical properties of compact bone, significantly increasing the strength of the femoral neck (p < 0.05), and tending to increase the strength of the femoral diaphysis. Ranitidine did not significantly affect the investigated parameters, and betahistine decreased the strength of the tibial metaphysis (cancellous bone, p < 0.01). There were no significant effects of the drugs on serum bone turnover markers. In estrogen-deficient rats, the drugs did not significantly affect the investigated skeletal parameters. In conclusion, the effects of histamine H(1), H(2) and H(3) receptor antagonists on the skeletal system in rats were differential and dependent on estrogen status.

Reducing olanzapine-induced weight gain side effect by using betahistine: a study in the rat model

Olanzapine is effective at treating multiple domains of schizophrenia symptoms. However, it induces serious metabolic side effects. Antipsychotic drug's antagonistic affinity to histamine H₁ receptors has been identified as a main contributor for weight gain/obesity side effects. This study therefore investigated whether a combined treatment of betahistine (a H₁ receptor agonist and H₃ receptor antagonist) could reduce the body weight/obesity induced by olanzapine. Female Sprague Dawley rats were treated orally with olanzapine (1 mg/kg, t.i.d.) and/or betahistine (2.67 mg/kg, t.i.d.), or vehicle for two weeks. Rats treated with olanzapine exhibited significant body weight gain and increased food intake. Co-treatment of olanzapine with betahistine significantly prevented (-45%) weight gain and reduced feeding efficiency compared to sole olanzapine treatment. Betahistine treatment alone had no effect on weight gain and food intake. Olanzapine reduced locomotor activity, but not betahistine. These findings demonstrate that olanzapine-induced body weight gain can partially be reduced by co-treatment with betahistine. Betahistine has H₃ receptor antagonistic effects to increase histamine release, which may augment its direct agonistic effects on H₁ receptors. These findings have important implications for clinical trials using betahistine to control antipsychotic-induced obesity side effects.

Comparison of the therapeutic efficacy of a fixed low-dose combination of cinnarizine and dimenhydrinate with betahistine in vestibular neuritis: a randomized, double-blind, non-inferiority study

BACKGROUND

Vestibular neuritis (VN) is a strongly disabling disease of the peripheral vestibular system. Rapid and effective relief of symptoms is important to allow patients to promptly return to normal physical activity.

OBJECTIVE

The aim of this prospective, randomized, double-blind study was to evaluate the efficacy of a fixed low-dose combination of cinnarizine and dimenhydrinate in unilateral VN in comparison with betahistine in terms of improvement of vertigo and concomitant symptoms, and performance in neurotological testing.

METHODS

Sixty-two patients were randomized to receive either cinnarizine 20 mg/dimenhydrinate 40 mg as a fixed combination or betahistine 12 mg, each three times daily for 4 weeks. Vertigo and concomitant symptoms, activities of daily living (ADL), posturography and a battery of vestibulo-ocular tests, registered by electronystagmography including spontaneous nystagmus, bithermal caloric and rotatory test, among others, were assessed at baseline (t(0)), after 1 week (t(1w)) and after 4 weeks (t(4w)). The primary endpoint was the Mean Vertigo Score (MVS) at t(1w), a composite of 12 individual scores for unprovoked and provoked vertigo, each assessed using a 10 cm visual analogue scale (VAS). Non-inferiority of the fixed combination versus betahistine would be assumed if the two-sided 95% confidence intervals (CIs) for between-group differences in MVS lay entirely below the non-inferiority margin of 1.25 (12.5% of VAS range).

RESULTS

The fixed combination led to significantly greater improvements in MVS than betahistine both at t(1w) (primary endpoint) and at t(4w) (95% CI for the difference in baseline-adjusted means -0.95, -0.64 at t(1w), -0.77, -0.44 at t(4w); p < 0.001). Vegetative symptoms and ADL also improved significantly more under the fixed combination than under betahistine at t(1w) (p < 0.001, each parameter) and t(4w) (p < 0.001 and p < 0.01, respectively), both showing a nearly complete remission at t(4w). In the two groups, pathological posturography and electronystagmography parameters normalized during the 4-week treatment. The fixed combination group showed an earlier recovery of spontaneous nystagmus than the betahistine group (t(1w), p < 0.001) and slightly higher improvements in asymmetry of rotation-induced nystagmus at t(1w) and t(4w) (p = 0.041, each time point). No significant differences were found between the treatments in abatement of spontaneous nystagmus at t(4w) and decrease of caloric lateralization or improvement of equilibrium (sensory organization test [SOT], conditions 5/6) at t(1w) and t(4w). No patient reported any adverse event.

CONCLUSION

The results showed that the fixed low-dose combination of cinnarizine and dimenhydrinate is an effective and well tolerated option for symptomatic treatment in unilateral VN. The fixed combination led to significant improvements in vertigo and ADL within the first week, and to a nearly complete recovery after 4 weeks. Neurotological testing revealed no signs of a possible detrimental influence of the 4-week treatment with the fixed combination compared with betahistine in terms of recovery of caloric responsiveness and abatement of rotation-induced nystagmus.

High-dosage betahistine dihydrochloride between 288 and 480 mg/day in patients with severe Menière's disease: a case series

The objective of this study was to evaluate the clinical benefit and the side effects of high dosages of betahistine dihydrochloride (288-480 mg/day) in patients with severe Menière's disease (MD). In this case series 11 patients with MD who had not responded sufficiently to a dosage of 144 mg/day of betahistine dihydrochloride were treated on an individual basis with daily dosages between 288 and 480 mg of betahistine dihydrochloride. The number of attacks per month and the side effects were monitored. Non-parametric tests were used for statistical analysis. As a result, the frequency and the severity of vertigo were significantly reduced in all patients. The side effects were mild, self-limiting, and did not require any change in the treatment strategy. Despite the considerable limitations of an observational study--in particular in MD--high dosages of betahistine dihydrochloride between 288 and 480 mg/day seem to be effective in patients who do not sufficiently respond to lower dosages. Moreover, such dosages are well tolerated.

Allergic and immunologic features of Ménière's disease

Ménière's disease (MD), which by definition is idiopathic, has been ascribed to various causes, including both inhalant and food allergies. Patients with MD report higher rates of allergy history and positive skin or in vitro tests compared with a control group of patients with other otologic diseases and to the general public. Recent immunologic studies have shown higher rates of circulating immune complexes, CD4, and other immunologic components in patients with MD compared with healthy controls. Published treatment results have shown benefit from immunotherapy and/or dietary restriction for symptoms of MD in those patients who present with both allergy and MD.

Acute effects of betahistine hydrochloride on food intake and appetite in obese women: a randomized, placebo-controlled trial

BACKGROUND

Central nervous system histaminergic tone is thought to play a role in appetite regulation. In animal models, histamine receptor 1 (HRH1) agonists and histamine receptor 3 (HRH3) antagonists decrease food intake.

OBJECTIVE

The objective of this study was to examine the acute effects of betahistine hydrochloride (an HRH1 agonist and HRH3 antagonist) on food intakes and appetites.

DESIGN

The study was a proof-of-concept, randomized, double-blinded, placebo-controlled, dose-ranging study performed to examine the effects of betahistine in women with class I or II obesity [body mass index (BMI; in kg/m²) of 30-39.99]. After a 24-h placebo run-in period, subjects received a placebo (n = 19) or 48 (n = 19), 96 (n = 17), or 144 (n = 21) mg betahistine/d for 24 h. Treatment was followed by a buffet test meal to assess energy intake. Hunger, satiety, and desire to eat were measured after consuming the meal by using visual analog scales. Data were analyzed by using regression models with the assumption that there would be an increasing effect of betahistine doses. Analyses were adjusted for age, log fat and lean mass, food preferences, and intake during a buffet test meal obtained during the placebo run-in period.

RESULTS

Of the 79 obese women (mean ± SD age: 42 ± 11 y; BMI: 35 ± 3) enrolled in the study, 76 women completed the study. The betahistine dose did not significantly change intakes from those observed during the run-in period of the buffet test meal (P = 0.78). Hunger, fullness, and desire to eat (all P > 0.62) similarly showed no differences according to the betahistine dose.

CONCLUSIONS

Betahistine did not produce an effect on food intakes or appetites. More potent histaminergic modulators may be required to elucidate the possible role of histaminergic pathways in human obesity. This trial was registered at clinicaltrials.gov as NCT00459992.