Pharmacokinetics of benzydamine after intravenous, oral, and topical doses to human subjects

The Effect of Topical Benzydamine Hydrochloride and Cuff Pressure Monitorization on Postoperative Sore Throat Due to Intubation

OBJECTIVE

Postoperative sore throat (POST) is the most common discomfort after endotracheal intubation. Damage to the tracheal mucosa caused by inappropriate endotracheal tube (ETT) cuff pressure has been shown as the major factor. Monitoring the ETT cuff pressure at a certain value reduces this damage. Benzydamine hydrochloride (BH) has proven to be effective on sore throat and studies have shown that it is also effective on POST. In this study, the efficacy of BH and ETT cuff pressure monitoring on POST was evaluated.

MATERIALS AND METHODS

After ethics committee approval 210 patients in the ASA (American Society of Anesthesiologists) I-III risk group undergoing elective surgery were included in the study. Routine anesthesia monitoring, induction, and maintenance were provided. Patients were randomly divided into three groups. Thirty minutes before surgery, the posterior pharyngeal wall was sprayed with BH in group 1 and distilled water in groups 2 and 3. Intraoperatively, the first and second groups were monitored to keep the ETT cuff pressure between 22 and 26 cmH2O, while no intervention was performed in the third group. The incidence and severity of postoperative dysphagia, hoarseness, and POST were questioned.

RESULTS

There was no difference between demographic data, and gender was not associated with POST. There was a statistically significant difference between the first and second groups and the third group in terms of all three symptoms questioned (p<0.01). No difference was observed between the first and second groups. Side effect rates were similar. Smoking was not found to be associated with symptoms.

CONCLUSION

The incidence and severity of POST, dysphagia, and hoarseness are reduced when the ETT cuff is inflated with a pressure of 22-26 cmH2O after intubation with a manometer and maintained at this pressure range throughout the operation. There was no beneficial effect of BH.

Novel Sprayable Thermosensitive Benzydamine Hydrogels for Topical Application: Development, Characterization, and In Vitro Biological Activities

Benzydamine hydrochloride (BZD) having analgesic, anesthetic, and anti-inflammatory effects is used orally or topically in the treatment of disorders such as joint inflammation and muscle pain. Within the scope of this study, sprayable thermosensitive BZD hydrogels were developed using thermoresponsive poloxamers to avoid systemic side effects and to provide better compliance for topical administration. Also, hydroxypropyl methyl cellulose (HPMC) was employed to improve the mechanical strength and bioadhesive properties of the hydrogel. The addition of BZD generally decreased the viscosity of the formulations (p < 0.05), while increasing the gelation temperature (p < 0.05). The formulations that did not have any clogs or leaks in the nozzle of the bottle during the spraying process were considered lead formulations. To spray the formulations easily, it was found that the viscosity at RT should be less than 200 mPa·s, and their gelation temperature should be between 26 and 34°C. Increasing HPMC and poloxamer improved bioadhesion. The amount of HPMC and poloxamers did not cause a significant change in the release characteristics of the formulations (p > 0.05); the release profiles of BZD from the formulations were similar according to model-independent kinetic (f2 > 50). HPMC and poloxamers had important roles in the accumulation of BZD in the skin. In vitro biological activity studies demonstrated that the formulations presented their anti-inflammatory activity with TNF-α inhibition but did not have any effect on the inhibition of COX enzymes as expected. As a result, thermosensitive hydrogels containing BZD might be an appropriate alternative, providing an advantage in terms of easier application compared to conventional gels.

Benzydamine-An Affordable Over-the-Counter Drug with Psychoactive Properties-From Chemical Structure to Possible Pharmacological Properties

Benzydamine is a non-steroidal anti-inflammatory drug with distinct pharmacological properties from other compounds in the same therapeutic class. The differences are structural and pharmacological in nature; the anti-inflammatory mechanism is not strictly explained by the ability to interfere with the synthesis of prostaglandins. The compound is used strictly in local inflammatory diseases (inflammation in the oral and vaginal mucosa). In addition to the therapeutic indications found in the summary of product characteristics (SPC), the compound is used, in high doses, as a psychotropic substance for oral administration, having similar properties to lysergic acid diethylamide (LSD). As an over-the-counter (OTC) compound, it is easy to obtain, and the consequences of using it for purposes other than those assumed by the manufacturer raise various concerns. The reasons are related to the pharmacodynamic and pharmaco-toxicological properties, since neither the mechanism of action nor the possible side effects that would result from systemic consumption, in high doses, even occasionally, have been fully elucidated. The present review aims to analyze the pharmacodynamic properties of benzydamine, starting from the chemical structure, by comparison with structurally similar compounds registered in therapy (as an anti-inflammatory or analgesic) or used for recreational purposes.

Comparative evaluation of rapidity of action of benzydamine hydrochloride 0.3% oromucosal spray and benzydamine hydrochloride 3 mg lozenges in patients with acute sore throat: A phase IV randomized trial

BACKGROUND

Acute sore throat (ST) can occur as part of a common cold of viral origin or caused by pharyngeal bacterial pathogens. The majority of patients with acute ST complain of pain on swallowing and dry scratchiness which can have a negative impact on the quality of life (QoL). This study aimed to evaluate the time to pain relief in patients with acute ST, following a single administration of benzydamine hydrochloride (HCl) 0.3% oromucosal spray or benzydamine HCl 3 mg lozenges.

METHODS

This multicenter, randomized, active-controlled, open label, parallel-group, international phase IV study was conducted at 12 investigational centers in Poland, Hungary, and Russian Federation. The study population consisted of 363 adult patients with recent onset (≤3 days) of ST and a diagnosis of tonsillopharyngitis. The primary endpoint was to assess the efficacy of benzydamine HCl in ST pain relief at 2 minutes after a single-dose administration. Secondary endpoints included, among others, the assessment of a first perceived ST relief at 1 minute after a single-dose administration of benzydamine HCl spray or lozenge.

RESULTS

Both the spray and lozenges are effective in providing a ST relief starting already at 2 minutes after a single administration, with an effect lasting up to up to 4 hours. Clinical efficacy after 7 days of treatment and a good safety profile were also demonstrated.

CONCLUSION

Anesthetic and analgesic properties of benzydamine spray and lozenges effectively addressed the patient priority of a rapid relief of symptoms of upper respiratory tract infections (URTI).

Casein Micelles as Nanocarriers for Benzydamine Delivery

The aim of the present work was to optimize the process parameters of the nano spray drying technique for the formulation of benzydamine-loaded casein nanoparticles and to investigate the effect of some process variables on the structural and morphological characteristics and release behavior. The obtained particles were characterized in terms of particle size and size distribution, surface morphology, production yield and encapsulation efficiency, drug-polymer compatibility, etc., using dynamic light scattering, scanning electron microscopy, differential scanning calorimetry, and Fourier transformed infrared spectroscopy. Production yields of the blank nanoparticles were significantly influenced by the concentration of both casein and the crosslinking agent. The formulated drug-loaded nanoparticles had an average particle size of 135.9 nm to 994.2 nm. Drug loading varied from 16.02% to 57.41% and the encapsulation efficiency was in the range 34.61% to 78.82%. Our study has demonstrated that all the investigated parameters depended greatly on the polymer/drug ratio and the drug release study confirmed the feasibility of the developed nanocarriers for prolonged delivery of benzydamine.

The Benzydamine Experience: A Systematic Review of Benzydamine Abuse

BACKGROUND

Both prescription and over-the-counter (OTC) drugs recently emerged among novel psychoactive substances (NPS) being reported as ingested for recreational purposes. Among them, benzydamine (BZY), normally prescribed as an OTC anti-inflammatory drug, is reportedly being diverted and recreationally used.

OBJECTIVE

The aim of this study was to investigate how the misuse of BZY has been reported, illustrating its psychotropic molecular mechanism, and studying its psychopathological effects.

METHODS

We firstly conducted a systematic review of the literature concerning the abuse of BZY and its effects. For data gathering purposes, both PRISMA and PROSPERO guidelines were followed. All research methods were approved by PROSPERO (identification code CRD42020187266). Second, we analysed BZY-related data from the European Monitoring Agency (EMA) Adverse Drug Reactions (ADRs) database recorded during 2005-2020 regarding its abuse.

RESULTS

Eleven articles, published during 1997-2019, were included in our systematic review, including five case reports, four surveys, and two retrospective case series analyses. While nine articles dealt with the recreational use of BZY, two described an oral overdose of the drug. When specified, dosages of BZY consumed ranged from 500 to 1500mg. The EMA dataset contained three cases of BZY abuse.

CONCLUSION

Results from the systematic review showed BZY might be diverted for typical hallucinogenic properties occurring at high dosages. Healthcare professionals should be warned about a possible misuse/abuse of a commonly prescribed anti-inflammatory drug and be vigilant when prescribing it. Physicians working in emergency units should know that psychotic symptoms may be related to BZY abuse.

Ambient-Temperature Synthesis of (E)-N-(3-(tert-Butyl)-1-methyl-1H-pyrazol-5-yl)-1-(pyridin-2-yl)methanimine

We report the ambient-temperature synthesis of novel (E)-N-(3-(tert-butyl)-1-methyl-1H-pyrazol-5-yl)-1-(pyridin-2-yl)methanamine 3 in 81% yield by a condensation reaction between 3-(tert-butyl)-1-methyl-1H-pyrazol-5-amine 1 and 2-pyridinecarboxaldehyde 2 in methanol using magnesium sulfate as a drying agent. The N-pyrazolyl imine 3 was full characterized by IR, 1D, and 2D NMR spectroscopy, mass spectrometry, and elemental analysis.

Effect of St. John's wort oil and olive oil on the postoperative complications after third molar surgery: randomized, double-blind clinical trial

OBJECTIVES

This multicenter study aimed to evaluate the effects of St. John's wort oil and virgin olive oil on the postoperative complications and compare this with chlorhexidine gluconate plus benzydamine hydrochloride mouthwash after the removal of impacted third molar.

METHODS

A total of 90 patients in need of impacted third molar surgery were included in this study. All included patients were randomly divided into 3 groups. The patients in group 1 received St. John's wort oil; the patients in group 2 received virgin olive oil, and those in group 3 received mouthwash containing chlorhexidine gluconate plus benzydamine hydrochloride. The self-reported pain and difficulty during jaw function, trismus, facial swelling, number of analgesics used during first postoperative week, and postoperative periodontal condition including plaque accumulation, bleeding on probing, and periodontal pocket depth were compared between the groups.

RESULTS

No significant differences were found regarding the study variables.

CONCLUSIONS

The data of the present study supports that the use of essential oils provides efficient alternative to the gold standard chlorhexidine gluconate mouthwash in reducing postoperative complications and improving healing process without adverse effects after surgical removal of impacted third molars.

CLINICAL RELEVANCE

The use of essential oils showed similar results as the chlorhexidine gluconate mouthwash regarding swelling, mouth opening, pain, need for rescue medication, infectious complications (i.e., alveolar osteitis), and periodontal healing. Therefore, essential oils can be an alternative to routine mouthwashes to ensure oral hygiene after impacted third molar surgery.

Phase I Study in Healthy Women of a Novel Antimycotic Vaginal Ovule Combining Econazole and Benzydamine

Purpose

A novel fixed-dose combination of 150 mg of econazole with 6 mg of benzydamine formulated in vaginal ovules was investigated in a randomised, double-blind, four-parallel group, tolerability, and pharmacokinetic Phase I study in healthy women.

Methods

The fixed-dose combination was compared to econazole and benzydamine single-drug formulations and with placebo after daily applications for 3 consecutive days. Safety and tolerability were evaluated recording the adverse drug reactions, local and general tolerability scores, clinical laboratory assays, and vital signs. Econazole, benzydamine, and its metabolite benzydamine N-oxide pharmacokinetics were investigated after single and multiple applications.

Results

Local reactions were generally absent. Pruritus and pain at the application site were infrequently reported. According to the subjects' evaluations, the overall tolerability of the ovules was rated as excellent or good. No significant effect of any treatment on laboratory parameters, vital signs, body weight, vaginal pH, or ECG was observed. Very low econazole, benzydamine, and benzydamine-N-oxide concentrations were measured in plasma, though quantifiable in almost all samples.

Conclusion

The tested fixed-dose combination showed a good safety profile consistently with the known tolerability of both active substances. In addition, the confirmed low bioavailability of the drugs excludes the possibility of any accumulation effects and limits the risk of undesired systemic effects. This trial is registered at ClinicalTrials.gov with the identifier NCT02720783 last updated on 07 February 2017.

Effects of benzydamine hydrochloride on postoperative sore throat after extubation in children: a randomized controlled trial

BACKGROUND

Postoperative sore throat (POST) is a common, undesirable result of endotracheal intubation during general anaesthesia. This study aimed to evaluate the effectiveness of benzydamine hydrochloride (BH) spray in reducing the incidence of POST in paediatric patients.

METHODS

This randomized, double-blind, prospective study included 142 children 6-12 years of age, who were randomly assigned to receive either BH spray or control. After induction of anaesthesia, direct laryngoscope was placed and BH spray was applied to the upper trachea and vocal cord in the BH group and intubation was performed using a cuffed tube lubricated with normal saline. Intubation in the control group was performed using a cuffed tube lubricated with normal saline without any intervention. The balloon was inflated to a pressure of 20 cmH2O. Patients were extubated after fully awakened and transferred to the post-anaesthetic care unit (PACU), where they were examined for the presence of POST and any adverse events 30 min after arrival to the PACU. Postoperative pain was evaluated using a smartphone application.

RESULTS

Seventy-one patients were allocated to each group. The incidence of POST in the BH group did not differ from that in the control group (control: BH = 35 (49.3%): 42 (59.2%); P = 0.238); postoperative pain was also similar between the groups. Other complications, such as breath holding, secretions, coughing, laryngospasm and desaturation events, did not differ between the groups.

CONCLUSIONS

Application of prophylactic BH spray to the vocal cords and upper trachea was not proven to reduce POST in paediatric patients.

TRIAL REGISTRY

NCT03074968 (ClinicalTrials.gov, Feb 26, 2017).

Chronic psychosis related to benzydamine hydrochloride abuse

Benzydamine hydrochloride is a non-steroidal anti-inflammatory drug with analgesic and antipyretic effects. In those who use medicines containing this agent at high doses (500-3000 mg), some adverse effects such as hallucinosis, stimulant effects in the central nervous system, paranoia, and convulsions can be seen. The drug is vulnerable to abuse because of the stimulant effects on the central nervous system. In this paper, we present a young male patient with symptoms of psychosis due to benzydamine hydrochloride abuse. He was admitted to the psychiatry outpatient clinic with visual hallucinations, fear, and insomnia. His symptoms started after taking 10 tablets of benzydamine hydrochloride (500 mg) 6 months ago, which continued for 1-2 days and spontaneously resolved. The patient used high doses of the drug 3-4 times over a period of 3 months. Although his last drug intake was 3 months ago, his symptoms continued at the time of admission to the clinic. A neurologic examination and detailed laboratory tests of the patient revealed no evidence of a cause for psychotic symptoms. The patient was scheduled to undergo oral antipsychotic therapy. Although similar cases have been reported in the literature, this is the only case in which psychosis was still present despite discontinuation of the drug. Our aim was to contribute to the literature on the use of BH in causing chronic psychosis and to draw attention to the growing number of BH abuse cases.

An Investigation into the Prediction of the Plasma Concentration-Time Profile and Its Interindividual Variability for a Range of Flavin-Containing Monooxygenase Substrates Using a Physiologically Based Pharmacokinetic Modeling Approach

Our recent paper demonstrated the ability to predict in vivo clearance of flavin-containing monooxygenase (FMO) drug substrates using in vitro human hepatocyte and human liver microsomal intrinsic clearance with standard scaling approaches. In this paper, we apply a physiologically based pharmacokinetic (PBPK) modeling and simulation approach (M&S) to predict the clearance, area under the curve (AUC), and C_max values together with the plasma profile of a range of drugs from the original study. The human physiologic parameters for FMO, such as enzyme abundance in liver, kidney, and gut, were derived from in vitro data and clinical pharmacogenetics studies. The drugs investigated include itopride, benzydamine, tozasertib, tamoxifen, moclobemide, imipramine, clozapine, ranitidine, and olanzapine. The fraction metabolized by FMO for these drugs ranged from 21% to 96%. The developed PBPK models were verified with data from multiple clinical studies. An attempt was made to estimate the scaling factor for recombinant FMO (rFMO) using a parameter estimation approach and automated sensitivity analysis within the PBPK platform. Simulated oral clearance using in vitro hepatocyte data and associated extrahepatic FMO data predicts the observed in vivo plasma concentration profile reasonably well and predicts the AUC for all of the FMO substrates within 2-fold of the observed clinical data; seven of the nine compounds fell within 2-fold when human liver microsomal data were used. rFMO overpredicted the AUC by approximately 2.5-fold for three of the nine compounds. Applying a calculated intersystem extrapolation scalar or tissue-specific scalar for the rFMO data resulted in better prediction of clinical data. The PBPK M&S results from this study demonstrate that human hepatocytes and human liver microsomes can be used along with our standard scaling approaches to predict human in vivo pharmacokinetic parameters for FMO substrates.

An Investigation into the Prediction of in Vivo Clearance for a Range of Flavin-containing Monooxygenase Substrates

Flavin-containing monooxygenases (FMO) are metabolic enzymes mediating the oxygenation of nucleophilic atoms such as nitrogen, sulfur, phosphorus, and selenium. These enzymes share similar properties to the cytochrome P450 system but can be differentiated through heat inactivation and selective substrate inhibition by methimazole. This study investigated 10 compounds with varying degrees of FMO involvement to determine the nature of the correlation between human in vitro and in vivo unbound intrinsic clearance. To confirm and quantify the extent of FMO involvement six of the compounds were investigated in human liver microsomal (HLM) in vitro assays using heat inactivation and methimazole substrate inhibition. Under these conditions FMO contribution varied from 21% (imipramine) to 96% (itopride). Human hepatocyte and HLM intrinsic clearance (CL_int) data were scaled using standard methods to determine the predicted unbound intrinsic clearance (predicted CL_{int u}) for each compound. This was compared with observed unbound intrinsic clearance (observed CL_{int u}) values back calculated from human pharmacokinetic studies. A good correlation was observed between the predicted and observed CL_{int u} using hepatocytes (R² = 0.69), with 8 of the 10 compounds investigated within or close to a factor of 2. For HLM the in vitro-in vivo correlation was maintained (R² = 0.84) but the accuracy was reduced with only 3 out of 10 compounds falling within, or close to, twofold. This study demonstrates that human hepatocytes and HLM can be used with standard scaling approaches to predict the human in vivo clearance for FMO substrates.

Effect of Intracuff Lidocaine on Postoperative Sore Throat and the Emergence Phenomenon: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Postoperative sore throat and other airway morbidities are common and troublesome after endotracheal tube intubation general anesthesia (ETGA). We propose lidocaine as endotracheal tube (ETT) cuff inflation media to reduce the postintubation-related emergence phenomenon.

METHODS

We searched PubMed, EMBASE, and Cochrane databases systematically for randomized controlled trials (RCTs) that have investigated the outcome of intracuff lidocaine versus air or saline in patients receiving ETGA. Using a random-effects model, we conducted a meta-analysis to assess the relative risks (RRs) and mean difference (MD) of the incidence and intensity of relevant adverse outcomes.

RESULTS

We reviewed nineteen trials, which comprised 1566 patients. The incidence of early- and late-phase postoperative sore throat (POST), coughing, agitation, hoarseness, and dysphonia decreased significantly in lidocaine groups, with RRs of 0.46 (95% confidence interval [CI]: 0.31 to 0.68), 0.41 (95% CI: 0.25 to 0.66), 0.43 (95% CI: 0.31 to 0.62), 0.37 (95% CI: 0.25 to 0.55), 0.43 (95% CI: 0.29 to 0.63), and 0.19 (95% CI: 0.08 to 0.5), respectively, when compared with the control groups. The severity of POST also reduced significantly (mean difference [MD] -16.43 mm, 95% CI: -21.48 to -11.38) at 1 h and (MD -10.22 mm, 95% CI: -13.5 to -6.94) at 24 h. Both alkalinized and non-alkalinized lidocaine in the subgroup analyses showed significant benefits in emergence phenomena prevention compared with the control.

CONCLUSION

Our results indicate that both alkalinized and non-alkalinized intracuff lidocaine may prevent and alleviate POST and postintubation-related emergence phenomena.

Prenatal sonographic diagnosis of premature constriction of the fetal ductus arteriosus after maternal self-medication with benzydamine hydrochloride: report of 3 cases and review of the literature

We report 3 cases of prenatal diagnosis of premature constriction of the ductus arteriosus after maternal benzydamine hydrochloride therapy (3-mg lozenges) in third-trimester pregnancies. In each case, fetal echocardiography revealed a dilated, hypocontractile right ventricle with severe tricuspid regurgitation and constriction of the ductus arteriosus. Although the effect of indomethacin and other nonsteroidal anti-inflammatory drugs on prenatal ductal constriction is well known, readily available over-the-counter nonsteroidal anti-inflammatory drugs such as benzydamine can have an equally deleterious effect and are best avoided in the third trimester of pregnancy.

Oral ingestion of a topical benzydamine hydrochloride-containing gynaecological preparation in association with television advertising in Italy: analysis of cases managed by a National Poison Control Centre

Objective To evaluate the impact of a television advertising campaign on the risk of oral ingestion of a topical non-prescription gynaecological preparation containing benzydamine hydrochloride. Design An interrupted time series design with data routinely collected. Setting A National Poison Control Centre. Participants 215 cases of hazardous exposure to the preparation under study occurred in Italy from January 2005 to December 2010. Primary and secondary outcome measures Mean daily rate of cases of exposure by gender in three different periods, that is, pre-advertisement period, before the advertisement was broadcast (from 1 January 2005 to 19 December 2009), advertisement period, when the advertisement was repeatedly launched (from 20 December 2009 to 27 February 2010), post-advertisement period (from 28 February 2010 to 6 March 2010); observed/expected ratios of cases, with expected cases based on data from the pre-advertisement period, adjusted for estimated variations in the number of users. Comparison of the distribution of the main characteristics of cases in the three different periods by means of Pearson's χ(2) test or Fisher's exact test. Results The adjusted observed/expected ratio of cases in women was 7.48 (95% CI 5.76 to 9.56) in the advertisement period and 2.97 (95% CI 2.24 to 3.85) in the post-advertisement period. Regarding the characteristics of cases, there was an increased proportion of cases of exposure due to confusion about the correct administration route in the advertisement and post-advertisement periods (81% and 55%, respectively, compared to 16% for the pre-advertisement period.) and of individuals with clinical effects (55%, 52% and 27%, respectively). Conclusions In Italy, an advertisement for a non-prescription medicine seems to have confused consumers regarding the administration route. This effect was observed even after the advertisement had stopped being broadcast. These results highlight the need for the monitoring of medication errors and adverse effects before, during and after advertising.

Efficacy of topical benzydamine hydrochloride gel on oral mucosal ulcers: an in vivo animal study

The aim of this study was to investigate the effect of benzydamine hydrochloride bioadhesive gel on healing of oral mucosal ulceration in an animal model. For in vivo determination of the effects of the bioadhesive gel, 36 rabbits were separated into three groups: the first group was treated with the gel formulation without active agent, the second group with the gel formulation containing benzydamine, and the third group received no treatment. Clinical healing was established by measuring the area of the ulcer in each test group on days 3, 6, 9 and 12. Histological healing was determined on the same days. Benzydamine containing gel applications resulted in a decrease in the ulcer area in 12 days (p=0.000). Histological evaluation showed that the benzydamine group had a higher mean histological score than the base and the control groups during the whole test period, and the difference between the benzydamine group and the control group was significant (p=0.04). The bioadhesive gel formulation of benzydamine hydrochloride showed a statistically significant increased rate of mucosal repair in this experimental standard mucosal wound animal study. It is a candidate for the topical treatment of oral mucosal ulcerative lesions.

Effect on postoperative sore throat of spraying the endotracheal tube cuff with benzydamine hydrochloride, 10% lidocaine, and 2% lidocaine

BACKGROUND

Postoperative sore throat (POST) is a common complication after endotracheal intubation. We compared the effectiveness on POST of spraying the endotracheal tube (ETT) cuff with benzydamine hydrochloride, 10% lidocaine, and 2% lidocaine.

METHODS

Three hundred seventy-two patients were randomly allocated into 4 groups. The ETT cuffs in each group were sprayed with benzydamine hydrochloride, 10% lidocaine hydrochloride, 2% lidocaine hydrochloride, or normal saline before endotracheal intubation. After insertion, the cuffs were inflated to an airway leak pressure of 20 cm H(2)O. Anesthesia was maintained with propofol. The patients were examined for sore throat (none, mild, moderate, or severe) at 1, 6, 12, and 24 hours after extubation.

RESULTS

The highest incidence of POST occurred at 6 hours after extubation in all groups. There was a significantly lower incidence of POST in the benzydamine group than 10% lidocaine, 2% lidocaine, and normal saline groups (P < 0.05) at each observation time point. At 6 hours after extubation, the incidence of POST was significantly lower in the benzydamine group (17.0%) compared with 10% lidocaine (53.7%), 2% lidocaine (37.0%), and normal saline (40.8%) groups (P < 0.05). The benzydamine group had significantly decreased severity of POST compared with the 10% lidocaine, 2% lidocaine, and normal saline groups (P < 0.05) at each observation time point. Compared with the 2% lidocaine and normal saline groups, the 10% lidocaine group had significantly increased severity of POST at 1, 6, and 12 hours after extubation. There were no significant differences among groups in local or systemic side effects.

CONCLUSIONS

Spraying benzydamine hydrochloride on the ETT cuff is a simple and effective method to reduce the incidence and severity of POST.

Pharmacology of benzydamine

Benzydamine is a topical anti-inflammatory drug which is widely available and used topically for the treatment of the mouth. It is also used as a gel for application to inflamed joints. It has physicochemical properties and pharmacological activities which differ markedly from those of the aspirin-line non-steroidal anti-inflammatory drugs. Benzydamine is a weak base unlike the aspirin-like drugs which are acids or metabolized to acids. A major contrast with the aspirin-like drugs is that benzydamine is a weak inhibitor of the synthesis of prostaglandins but it has several properties which may contribute to its anti-inflammatory activity. These properties include inhibition of the synthesis of the inflammatory cytokine, tumour necrosis factor-alpha (EC(50), 25 micromol/L). Inhibition of the oxidative burst of neutrophils occurs under some conditions at concentrations of 30 to 100 micromol/L, concentrations which may be produced within oral tissues after local application. A further activity of benzydamine is a general activity known as membrane stabilization which is demonstrated by several actions including inhibition of granule release from neutrophils at concentrations ranging from 3 to 30 micromol/L and stabilization of lysosomes. Lack of knowledge of the tissue concentrations of benzydamine limit the correlation between pharmacological activities in vitro and in vivo. The concentration of benzydamine in the mouthwash is 4 mmol/L but the concentrations in oral tissues have not been studied adequately. Limited data in the rat indicates that concentrations of benzydamine in oral tissues are approximately 100 micromol/L.

Dexpanthenol pastille and benzydamine hydrochloride spray for the prevention of post-operative sore throat

BACKGROUND

In this study, we aimed to compare the effectiveness of dexpanthenol pastille and benzydamine hydrochloride spray on the prevention of a sore throat.

METHODS

One hundred and eighty patients undergoing general anaesthesia, who were ASA I-II and with their ages ranging between 15 and 70 years, were randomly allocated to three groups, each consisting of 60 patients. For group B, four puffs of benzydamine hydrochloride were sprayed into the mouth initially 30 min before the operation and repeatedly 5 min before anaesthesia induction. For group D, two pastilles of dexpanthenol were administered orally to be sucked 30 min before the operation. For group P, four puffs of distilled water were sprayed into the mouth initially 30 min before the operation. Post-operatively, patients were evaluated for a sore throat for the duration of 24 h.

RESULTS

The incidence of a sore throat was significantly lower for group D when compared with group B and group P. The incidence of a sore throat was similar for group B and group P. According to the sore throat grading system, the number of patients experiencing no complaints was significantly higher for group D when compared with group B and group P. The number of patients achieving moderate scores was significantly higher for group B when compared with group D.

CONCLUSION

The administration of 200 mg of dexpanthenol prophylactically before endotracheal intubation is effective in the prevention of post-operative sore throat.

Local irritant effects of topical oral sprays on oral mucosa in mice

Topical oral sprays are frequently used to prevent and manage oropharyngeal inflammation and lesions. This study investigated the histopathologic changes noted in the oral mucosa of mice after topical application of 3 widely prescribed antibacterial products. The 25 animals were divided into 5 groups and treated for 10 days with 2 sprays daily, as follows: group 1-chlorhexidine gluconate 0.12% + benzydamine hydrochloride 0.15%; group 2-benzydamine 0.27 mg/0.18 mL x 30 mL; group 3-chlorhexidine 0.2%; group 4-fusafungine 1%; and group 5 (cohort)-physiologic serum. On day 10 after drug administration, biopsy specimens were taken from the oropharyngeal mucosa of the tongue, the cheek mucosa, and the tongue base; these were examined under a light microscope and were classified as normal or pathologic. All topical oral sprays produced some degree of histopathologic change, such as hyperplasia, fibrosis, low-grade dysplasia, congestion, or edema. The local irritant effects of topical oral sprays should be considered when treatment is selected for patients with oropharyngeal disorder.

Effect of lipophilic counter-ions on membrane diffusion of benzydamine

Many topically applied drugs are ionized molecules that exhibit poor penetration across the lipid domains of the stratum corneum. Reduction of the charge on the molecule would be expected to enhance skin penetration. The objective of this study was to investigate the interaction of the non-steroidal anti-inflammatory drug benzydamine hydrochloride with suitable counter-ions including ibuprofen sodium. The influence of pH of the donor solution and hence degree of ionization on partitioning between n-octanol:buffer and the flux of benzydamine hydrochloride across polydimethyl siloxane (PDMS) membrane and human epidermis was determined. The maximum flux was determined at pH 7.6 when the fraction unionized was 2.51%, rather than at pH 9 when the fraction unionized was 38.7%. This suggests that at higher pH, although the permeability coefficient is increased, the decrease in solubility and therefore concentration of dissolved benzydamine in the medium results in a decrease in flux across the PDMS membrane. Ion-pair formation or interaction with each of the counter-ions was confirmed by NMR spectroscopy. Significant increases in logP and flux across PDMS membrane were determined for the ion-pairs (0.087, 12.54, 11.31, 0.121 microg cm(-2)h(-1) for benzydamine hydrochloride and ion-pairs with ibuprofen sodium, sodium benzoate and sodium octane sulfonate respectively). This study shows that it is possible to significantly enhance the flux of salts across a lipophilic membrane in the presence of counter-ions, resulting from intermolecular interaction and/or ion-pair formation.

Does Benzydamine Hydrochloride Applied Preemptively Reduce Sore Throat Due to Laryngeal Mask Airway?

Sore throat is a common postoperative complaint. We investigated whether preemptive benzydamine hydrochloride (BH) treatment could prevent sore throat due to a laryngeal mask airway (LMA) cuff inflated with air. One-hundred ASA status I-II patients who underwent general anesthesia were randomly divided into two groups. In the first group, four puffs of BH were applied to the pharynx 30 min before the operation and 5 min before the induction of anesthesia. Distilled water with a similar bottle was applied with the same protocol in the second group. Anesthetic induction was provided with propofol and fentanyl. The pressure of the LMA cuff inflated with room air was measured after the first adjustment and after 30, 60, and 90 min of inflation in both groups. At the end of operation, the LMA was removed after the recovery of spontaneous breathing. After the operation, patients were asked about sore throat symptoms at the first, second, and fourth hours. There were no significant differences between groups for cuff pressures, cuff volumes, analgesic doses, or operation times. However, sore throat symptoms were significantly less severe for the BH group during both resting and swallowing. In conclusion, preemptive topical BH may decrease the incidence of sore throat due to LMA use.

Biotransformation of benzydamine by microsomes and precision-cut slices prepared from cattle liver

1. Benzydamine (BZ), a non-steroidal anti-inflammatory drug used in human and veterinary medicine, is not licensed for use in food-producing species. Biotransformation of BZ in cattle has not been reported previously and is investigated here using liver microsomes and precision-cut liver slices. 2. BZ was metabolized by cattle liver microsomes to benzydamine N-oxide (BZ-NO) and monodesmethyl-BZ (Nor-BZ). Both reactions followed Michaelis-Menten kinetics (Km = 76.4 +/- 16.0 and 58.9 +/- 0.4 microM Vmax = 6.5 +/- 0.8 and 7.4 +/- 0.5 nmolmg(-1) min(-1) respectively); sensitivity to heat and pH suggested that the N-oxidation is catalysed by the flavin-containing monooxygenases. 3. BZ-NO and Nor-BZ were the most abundant products derived from liver slice incubations, and nine other BZ metabolites were found and tentatively identified by LC-MS. Desbenzylated and hydroxylated BZ-NO analogues and a hydroxylated product of BZ were detected, which have been reported in other species. Product ion mass spectra of other metabolites, which are described here for the first time, indicated the formation of a BZ N- -glucuronide and five hydroxylated and N+-glucuronidated derivatives of BZ, BZ-NO and Nor-BZ. 4. The results indicate that BZ is extensively metabolized in cattle. Clearly, differences in metabolism compared with, for example, rat and human, will need to be considered in the event of submission for marketing authorization for use in food animals.

Synthesis and biological evaluation of novel pyrazoles and indazoles as activators of the nitric oxide receptor, soluble guanylate cyclase

Database searching and compound screening identified 1-benzyl-3-(3-dimethylaminopropyloxy)indazole (benzydamine, 3) as a potent activator of the nitric oxide receptor, soluble guanylate cyclase. A comprehensive structure-activity relationship study surrounding 3 clearly showed that the indazole C-3 dimethylaminopropyloxy substituent was critical for enzyme activity. However replacement of the indazole ring of 3 by appropriately substituted pyrazoles maintained enzyme activity. Compounds were evaluated for inhibition of platelet aggregation and showed a general lipophilicity requirement. Aryl-substituted pyrazoles 32, 34, and 43 demonstrated potent activation of soluble guanylate cyclase and potent inhibition of platelet aggregation. Pharmacokinetic studies in rats showed that compound 32 exhibits modest oral bioavailability (12%). Furthermore 32 has an excellent selectivity profile notably showing no significant inhibition of phosphodiesterases or nitric oxide synthases.

Acute overdose due to benzydamine

Benzydamine is a nonsteroidal anti-inflammatory drug, currently available as mouthwash, aerosol, dermal cream, vaginal douche preparation, pills and otic drops. Up to now no cases of poisoning due to this drug have been reported. A 6-year-old girl with an accidental poisoning with benzydamine is described. The episode consisted of hallucinosis without other symptoms and resolved spontaneously in 17 h.

Pharmacokinetics of benzydamine in dairy cows following intravenous or intramuscular administration

Five lactating cows were given benzydamine hydrochloride by rapid intravenous (0.45 mg/kg) and by intramuscular (0.45 and 1.2 mg/kg) injection in a crossover design. The bioavailability, pharmacokinetic parameters and excretion in milk of benzydamine were evaluated. After intravenous administration, the disposition kinetics of benzydamine was best described using a two-compartment open model. Drug disposition and elimination were fast (t1/2 alpha: 11.13 +/- 3.76 min; t1/2 beta: 71.98 +/- 24.75 min; MRT 70.69 +/- 11.97 min). Benzydamine was widely distributed in the body fluids and tissues (Vd(area): 3.549 +/- 1.301 L/kg) and characterized by a high value for body clearance (33.00 +/- 5.54 ml/kg per min). After intramuscular administration the serum concentration-time curves fitted a one-compartment open model. Following a dose of 0.45 mg/kg, the Cmax value was 38.13 +/- 4.2 ng/ml at a tmax of 67.13 +/- 4.00 min; MAT and MRT were 207.33 +/- 22.64 min and 278.01 +/- 12.22 min, respectively. Benzydamine bioavailability was very high (92.07% +/- 7.08%). An increased intramuscular dose (1.2 mg/kg) resulted in longer serum persistence (MRT 420.34 +/- 86.39 min) of the drug, which was also detectable in milk samples collected from both the first and second milking after treatment.