Evaluation of the anticholinergic actions of glycopyrronium bromide

Muscarinic inhibition of salivary glands with glycopyrronium bromide does not reduce the uptake of PSMA-ligands or radioiodine

RATIONALE

Salivary glands are highly perfused and express the prostate-specific membrane antigen (PSMA) receptor as well as the sodium-iodide symporter. As a consequence, treatment with ¹⁷⁷Lu/²²⁵Ac-PSMA for prostate cancer or ¹³¹I for thyroid cancer leads to a high radiation dose in the salivary glands, and patients can be confronted with persistent xerostomia and reduced quality of life. Salivation can be inhibited using an antimuscarinic pharmaceutical, such as glycopyrronium bromide (GPB), which may also reduce perfusion. The primary objective of this work was to determine if inhibition with GPB could provide a considerable (> 30%) reduction in the accumulation of administered ¹²³I or ⁶⁸Ga-PSMA-11 in salivary glands.

METHODS

Ten patients who already received a whole-body ⁶⁸Ga-PSMA-11 PET/CT scan for (re)staging of prostate cancer underwent a repeat PET/CT scan with tracer administration at 90 min after intravenous injection of 0.2 mg GPB. Four patients in follow-up after thyroid cancer, who had been treated with one round of ablative ¹³¹I therapy with curative intent and had no signs of recurrence, received ¹²³I planar scintigraphy at 4 h after tracer administration without GPB and a repeated scan at least one week later, with tracer administration at 30 min after intramuscular injection of 0.4 mg GPB. Tracer uptake in the salivary glands was quantified on PET and scintigraphy, respectively, and values with and without GPB were compared.

RESULTS

No significant difference in PSMA uptake in the salivary glands was seen without or with GPB (Mean SUL_mean parotid glands control 5.57, intervention 5.72, p = 0.50. Mean SUL_mean submandibular glands control 6.25, intervention 5.89, p = 0.12). Three out of 4 patients showed increased ¹²³I uptake in the salivary glands after GPB (Mean counts per pixel control 8.60, intervention 11.46).

CONCLUSION

Muscarinic inhibition of salivation with GPB did not significantly reduce the uptake of PSMA-ligands or radioiodine in salivary glands, and can be dismissed as a potential strategy to reduce toxicity from radionuclide therapies.

Effect of Intramuscular Atropine Sulphate and Glycopyrrolate on Heart Rate and Salivary Secretion in Patients Undergoing Minor Oral Surgical Procedure

Introduction

In most of the oral surgical procedures performed under local anesthesia, we often face a great difficulty while performing surgeries because of reduced accessibility and visibility which is hampered by blood and saliva at the surgical site. Anticholinergic drugs like atropine sulphate and glycopyrrolate are commonly used as antisialogogue for patients undergoing a surgical procedure under general anesthesia with little or no side effects. 

Aims and objectives

To evaluate and compare the antisialogogue effect of atropine sulphate and glycopyrrolate in patients undergoing minor oral surgical procedures. To compare the efficacy of these drugs when administered intramuscularly and to evaluate their effects on heart rate in patients undergoing minor oral surgical procedures.

Materials and methods

Thirty patients undergoing minor oral surgical procedure were selected for the study. The patients were randomly assigned to receive either 0.6 mg/ml of Atropine Sulphate or 0.2 mg/ml of Glycopyrrolate intramuscularly. Salivary secretion, heart rate and arterial pressure were noted pre-injection and 30 minutes after the administration of the drug.

Results

Atropine sulphate and glycopyrrolate were equally potent as an antisialogogue. There was a significant increase in heart rate 30 min after the administration of atropine sulphate, but there was no significant change in heart rate in glycopyrrolate group.

Conclusion

Intramuscular gycopyrrolate is safer than intramuscular atropine sulphate as an antisialogogue in minor oral surgical procedures under local anesthesia.

Inhaled glycopyrrolate for the treatment of chronic obstructive pulmonary disease

Long-acting muscarinic antagonists (LAMAs), along with long-acting β2-agonists (LABAs), are the mainstay for treatment of patients with COPD. Glycopyrrolate, or glycopyrronium bromide, like other LAMAs, inhibits parasympathetic nerve impulses by selectively blocking the binding of acetylcholine to muscarinic receptors. Glycopyrrolate is unusual in that it preferentially binds to M3 over M2 muscarinic receptors, thereby specifically targeting the primary muscarinic receptor responsible for bronchoconstriction occurring in COPD. Inhaled glycopyrrolate is slowly absorbed from the lungs and rapidly eliminated from the bloodstream, most likely by renal excretion in its unmetabolized form, limiting the potential for systemic adverse events. Inhaled glycopyrrolate is a fast-acting, efficacious treatment option for patients with moderate-severe COPD. It improves lung function, reduces the risk of exacerbations, and alleviates the symptoms of breathlessness, which in turn may explain the improvement seen in patients' quality of life. Inhaled formulations containing glycopyrrolate are well tolerated, and despite being an anticholinergic, few cardiovascular-related events have been reported. Inhaled glycopyrrolate is thus of value as both monotherapy and in combination with other classes of medication for maintenance treatment of COPD. This review covers the mechanism of action of inhaled glycopyrrolate, including its pharmacokinetic, pharmacodynamic, and safety profiles, and effects on mucus secretion. It also discusses the use of inhaled glycopyrrolate in the treatment of COPD, as monotherapy and in fixed-dose combinations with LABAs and inhaled corticosteroid-LABAs, including a triple therapy recently approved in Europe.

Comparison of the Effects of Atropine and Glycopyrrolate on various End-Organs1

Atropine and glycopyrrolate (glycopyrronium bromide), a quaternary ammonium drug, were evaluated in volunteers following intramuscular administration with respect to effects on various end-organs with cholinergic innervation. Glycopyrrolate appears to be five to six times more potent than atropine in its antisialogogue effect and also exhibits a selective, though prolonged, effect on salivary secretion and sweat gland activity. It has minimal cardiovascular, ocular and central nervous system effects.

Intravenous Glycopyrrolate and Atropine at Induction of Anaesthesia: A Comparison1

In unpremedicated patients presenting for general anaesthesia for electroconvulsive therapy (ECT), the use of atropine combined with methohexitone as an intravenous induction agent was found to produce a significantly greater increase in heart rate than glycopyrrolate in similar combination. There was no difference in the antisialogogue effect of the two drugs at the doses used, and both drugs provided similar protection against the effects of suxamethonium and ECT on heart rate.

Preanaesthetic Medication: A Survey of Current Usage

A survey has been carried out amongst the UK based members of the Association of Anaesthetists of Great Britain and Ireland regarding their practice of premedication. Ninety-three per cent of respondents (reply rate 51.7%) used sedative-hypnotic premedication routinely in adults and 84% in children. However, anticholinergic premedication was used by only 36% in adults and 56% in children. Temazepam was the most frequently used sedative premedicant in adults and trimeprazine in children. Atropine and hyoscine were the most frequently used anticholinergic drugs. The main reasons for using sedative-hypnotic premedication were allaying anxiety and providing sedation. The main reasons for using anticholinergic drugs were drying of secretions and protection against vagal overactivity. This survey concludes that while sedative-hypnotic premedication continues to be used in the majority of patients with oral benzodiazepines the most frequently used drugs, the use of anticholinergic premedication continues to decline.

Paroxetine Useful for Palmar–Plantar Hyperhidrosis

Objective:

To report a case of palmar–plantar hyperhidrosis (PPH) In which paroxetine was found to be helpful.

Case Summary:

A 32-year-old man with a history of excessive sweating of the palms and soles since childhood was diagnosed with PPH and was prescribed paroxetine 10 mg/day, which was increased to 20 mg/day. After one month, he experienced a marked reduction in sweating and improvement in socio-occupational functioning, which were sustained during follow-up at 6 months without any emergent adverse effects.

Discussion:

Paroxetine's anticholinergic action may be responsible for its beneficial effect in PPH, as it may override the adrenergic mechanism, which has a minor effect on sweating from eccrine glands. Alternatively, paroxetine's beneficial effect in PPH may be secondary to its antianxiety effect, through central mechanisms.

Conclusions:

Paroxetine may be a useful option in the treatment of PPH.

Maprotiline (Ludiomil®, Ciba-Geigy Corp.)

Maprotiline is a tetracyclic compound representing a new chemical class of drugs with antidepressant activity. Comparison studies of maprotiline to amitriptyline and imipramine show equal efficacy in mixed depressive disorders. The use of mixed depressive populations in published studies has likely obscured any differences in efficacy that may exist between maprotiline and tricyclic antidepressants. Maprotiline is a specific norepinephrine re-uptake inhibitor with no effect on serotonergic activity. Peak blood levels after oral administration are reached in 9–16 hours, and the reported elimination half-life is 43 hours (range 27–58 hours). Maprotiline is equal in potency to amitriptyline and imipramine. The therapeutic dosage range is 150–300 mg/d, or 3 mg/kg/d, and maprotiline can be given once daily at bedtime. Sedative and anticholinergic effects are the most common side effects, and overdosage toxicity is similar to that seen with tricyclic antidepressants. Skin rashes are about twice as common with maprotiline compared to tricyclic antidepressants.

Glycopyrrolate oral solution: for chronic, severe drooling in pediatric patients with neurologic conditions

Chronic drooling (sialorrhea) is a common dysfunction in children with neurologic disorders such as cerebral palsy. Glycopyrrolate oral solution, an anticholinergic agent, is the first drug treatment approved in the US for drooling in children with neurologic conditions. This article reviews the clinical efficacy and tolerability of glycopyrrolate oral solution in pediatric patients with neurologic conditions and provides an overview of the pharmacological properties of the drug. In a phase III, randomized, double-blind, multicenter trial, children (aged 3-16 years; n = 36) with problem drooling associated with neurologic conditions and receiving glycopyrrolate oral solution had a significantly (p < 0.01) greater modified Teacher's Drooling Scale (mTDS) response rate at 8 weeks (primary endpoint) than those receiving placebo (73.7% vs 17.6%). At 24 weeks in an additional, noncomparative, phase III study, 52.3% of glycopyrrolate oral solution recipients (aged 3-18 years; n = 137) had an mTDS response (primary endpoint); the response rate was consistently above 50% at all 4-weekly timepoints, aside from the first assessment at week 4 (40.3%). In general, glycopyrrolate oral solution was well tolerated in clinical trials. The majority of adverse events were within expectations as characteristic anticholinergic outcomes.

Glycopyrrolate for chronic drooling in children

BACKGROUND

Sialorrhea, or drooling, is seen in the pediatric population, especially in patients with cerebral palsy and other neurodevelopmental disabilities. If medication use is warranted, anticholinergic agents are the drug of choice; however, adverse effects limit their use. Glycopyrrolate, a synthetic anticholinergic that acts at peripheral muscarinic receptors, has been used off-label for excessive drooling in children with neurodevelopmental disabilities for years. Product formulations restricted the use of glycopyrrolate. However, an oral solution was approved by the US Food and Drug Administration for children ages 3 to 16 years with neurologic disorders for chronic severe drooling in 2010; it became available for use in 2011.

OBJECTIVE

This article provides an overview of the pharmacology, clinical efficacy, and tolerability of glycopyrrolate when used for sialorrhea in children.

METHODS

To evaluate the efficacy and safety profile of glycopyrrolate for the treatment of sialorrhea in children, a comprehensive search was performed of the MEDLINE database (1966-February 25, 2012) and International Pharmaceutical Abstracts as well as references from additional review articles identified. Searches were conducted using the terms glycopyrrolate, sialorrhea, drooling, secretion, and pediatrics. The terms drug-induced and Parkinson disease-associated sialorrhea were excluded from the search. The pharmaceutical manufacturer of the oral solution was contacted for medical and study information.

RESULTS

Oral bioavailability of glycopyrrolate varies widely, with a median of 3.3%. Mean C(max) in children was determined to be 0.37 μg/mL, and mean T(max) was 3.1 hours. The clearance in children ranges from 0.6 to 1.43 L/kg/h. The t(½) ranges from 22 to 130 minutes and 19 to 99 minutes in infants and children, respectively. Six studies describing the use of glycopyrrolate for drooling in children were identified. A double-blind, crossover trial of 27 patients (age range, 4-19 years) demonstrated a reduced mean drooling score (modified Teacher's Drooling Scale [1 = never drools to 9 = clothing, hands, and objects frequently become wet]) for glycopyrrolate (mean highest tolerated dose, 0.11 mg/kg) compared with placebo of 1.85 versus 6.33 (P < 0.001). In a parallel study of 36 patients (age range, 3-16 years), 14 of 20 patients randomized to receive glycopyrrolate solution showed improvement in the mean modified Teacher's Drooling Scale score compared with only 3 patients receiving placebo (-3.5 vs -0.1, respectively). Glycopyrrolate was initiated at 0.02 mg/kg per dose orally TID (Max dose: 3 mg) and titrated over a 4-week period. Adverse effects identified in studies include dry mouth (9%-41%), constipation (9%-39%), and behavioral changes (18%-36%).

CONCLUSIONS

Glycopyrrolate is effective in decreasing sialorrhea in children with cerebral palsy or other neurodevelopmental disabilities. Adverse effects did occur, more frequently at higher doses, and should be monitored.

Pilot randomized clinical trial of an SSRI vs bupropion: effects on suicidal behavior, ideation, and mood in major depression

Randomized controlled trials in depressed patients selected for elevated suicidal risk are rare. The resultant lack of data leaves uncertainty about treatment in this population. This study compared a serotonin reuptake inhibitor with a noradrenergic/dopaminergic antidepressant in major depression with elevated suicidal risk factors. We conducted a double-blind, randomized, clinical pilot trial of paroxetine (N=36) or bupropion (N=38) in DSM IV major depression with a suicide attempt history or current suicidal ideation. The effects during acute (8 weeks) and continuation treatment (up to 16 weeks) were measured. Main outcomes were suicidal behavior and ideation. The secondary outcome was modified 17-item Hamilton Depression Rating Scale score subtracting the suicide item (mHDRS-17). Treatment was not associated with time to a suicidal event and no treatment main effect or treatment × time interaction on suicidal ideation or mHDRS-17 was found. Exploratory model selection showed modest advantages for paroxetine on: (1) mHDRS-17 (p=0.02); and (2) in a separate model adjusted for baseline depression, for suicidal ideation measured with the Beck Scale for Suicidal Ideation (p=0.03), with benefit increasing with baseline severity. Depressed patients with greater baseline suicidal ideation treated with paroxetine compared with bupropion appeared to experience greater acute improvement in suicidal ideation, after adjusting for global depression. Given the lack of evidence-based pharmacotherapy guidelines for suicidal, depressed patients-an important public health population-this preliminary finding merits further study.

Comparison of the efficacy and impact on cognition of glycopyrrolate and biperiden for clozapine-induced sialorrhea in schizophrenic patients: a randomized, double-blind, crossover study

BACKGROUND

Clozapine-induced sialorrhea (CIS) is a subjective distressing adverse effect and occurs in 31%-57% of schizophrenic patients receiving clozapine therapy. Current pharmacotherapy on CIS has focused on anticholinergic agents, even though they may impair cognitive function. Previous case reports have suggested the benefit of glycopyrrolate or biperiden in treating this condition, but no randomized controlled trial has provided evidence. The objective of our study was to evaluate the efficacy and impact on cognition of glycopyrrolate and biperiden treatments for schizophrenic patients suffering from CIS.

METHODS

Patients who satisfied the inclusion criteria entered a 12-week, randomized, double-blind, crossover, fixed-dose trial. The study consisted of two 4-week crossover phases, which were separated by a 4-week washout period. Sialorrhea and global cognitive function were assessed by using a Drooling Rating Scale (DRS) and the Mini Mental State Examination (MMSE), respectively.

RESULTS

Throughout the study, patients treated with glycopyrrolate or biperiden had significantly reduced DRS scores. Moreover, the DRS scores were significantly lower with glycopyrrolate treatment than with biperiden. In other respects, there were no significant differences in MMSE scores in patients treated with glycopyrrolate. However, we found a significant reduction in MMSE scores in patients treated with biperiden.

CONCLUSION

We provide evidence, for the first time, of the efficacy of glycopyrrolate and biperiden in the treatment of CIS. Furthermore, glycopyrrolate displays less impact on cognitive function. Consequently, glycopyrrolate can become a valid option for treating CIS. Observations from our study serve as a springboard for additional large-scale prospective trials.

Botulinum toxin for hyperhidrosis: a review

Primary focal hyperhidrosis is a disorder of idiopathic excessive sweating that typically affects the axillae, palms, soles, and face. The disorder, which affects up to 2.8% of the US population, is associated with considerable physical, psychosocial, and occupational impairments. Current therapeutic strategies include topical aluminum salts, tap-water iontophoresis, oral anticholinergic agents, local surgical approaches, and sympathectomies. These treatments, however, have been limited by a relatively high incidence of adverse effects and complications. Non-surgical treatment complications are typically transient, whereas those of surgical therapies may be permanent and significant. Recently, considerable evidence suggests that botulinum toxin type A (BTX-A) injections into hyperhidrotic areas can considerably reduce focal sweating in multiple areas without major adverse effects. BTX-A has therefore shown promise as a potential replacement for more invasive treatments after topical aluminum salts have failed. This article reviews the epidemiology, diagnosis, and management of primary focal hyperhidrosis, with an emphasis on recent research evidence supporting the use of BTX-A injections for this indication.

Current Therapeutic Options for Treating Primary Hyperhidrosis

Severe hyperhidrosis can cause extreme embarrassment that may lead to social and professional isolation. Therapeutic strategies to hyperhidrosis should employ the least invasive treatment that provides effective symptom control. The treatment options available for control of hyperhidrosis, non-surgical or surgical, differ in their invasiveness and efficacy. Mechanisms of action of antiperspirants, iontophoresis, cholinergic inhibitor drugs, botulinum toxin, and surgical sympathectomy are reviewed. There is little published evidence in the form of comparative randomised trials to support the use of one treatment over another. However, authors have tended to recommend those therapies that are available to their speciality. Specific therapies should be tailored to the patient's symptoms to gain maximum symptomatic improvement with minimum invasiveness and side-effects. To achieve this, the full range of treatment options should be available to, or accessible by the consulting doctor in order for the patient to have a meaningful choice.

Using anti-muscarinic drugs in the management of death rattle: evidence-based guidelines for palliative care

The management of 'death rattle' was reviewed by a task group on behalf of the Association for Palliative Medicine's Science Committee. Evidence was searched for the effectiveness of various anti-muscarinic drugs in drying oropharyngeal and bronchial secretions in dying patients. Clinical guidelines were constructed based on evidence from volunteer and clinical studies. Death rattle occurs in half of all dying patients and some response occurs in around 80% of treated patients. Clinical studies demonstrate that subcutaneous hyoscine hydrobromide 400 microg is more effective at improving symptoms at 30 min than glycopyrronium 200 microg by the same route. Volunteer studies demonstrate that intramuscular glycopyrronium 400 microg is as effective in drying secretions at 30 min as a dose of 200 microg given intravenously. Duration of response is shortest for hyoscine butylbromide (1 h) and longest for glycopyrronium (more than 6 h). There is insufficient evidence to support the use of one drug over another in a continuous infusion and prescribers should base decisions on different characteristics of each anti-muscarinic drug.

Xerostomic complaints induced by an anti-sialogogue in healthy young vs. older adults

Complaints of xerostomia and salivary hypofunction are common in older adults. However, recent studies reported that dehydration-induced salivary hypofunction caused fewer xerostomic complaints in older compared with young adults. This may predispose older adults to developing oral problems that will subsequently not receive attention from health care providers. Since many medications are known to inhibit salivation, this study attempted to determine if an anticholinergic drug (glycopyrrolate) had a differential effect on xerostomic complaints in young vs. older adults. Eighteen young (age 20-38 yrs) and 18 older (age 60-77 yrs) healthy adults were given a 4.0 micrograms/kg dose of i.v. glycopyrrolate. For 6 hrs after drug administration, stimulated parotid salivary flow was collected, and an eight-item Visual Analogue Scale (VAS) subjective xerostomia test was given. At several time points post-i.v. glycopyrrolate, salivary flow rates were consistently lower in older compared with young adults. For some measures of xerostomic complaint (time to first complaint; time to maximum complaint; mean maximum complaint), there were no age-related differences for all VAS items. However, a trend for increased xerostomic complaints in older adults was demonstrated (time to recovery; total duration of complaint; number xerostomic at 6 hrs). These findings suggest that, given equal doses of an anti-sialogogue, salivary hypofunction is greater in healthy older adults, while increased complaints of xerostomia are not as consistent.

A study comparing hyoscine hydrobromide and glycopyrrolate in the treatment of death rattle

This study looked at the efficacy of drug treatment in managing death rattle in a 30-bedded specialist palliative care unit. The study was conducted in two phases. In the first, patients received hyoscine hydrobromide as the antimuscarinic; glycopyrrolate was used in the second phase. The patients in the two phases were well matched for diagnosis, age, sex and duration of death rattle. A noise score scale of 0-3 was used, which was separately validated using a verbal rating scale and noise-meter readings. Noise scores were taken at the start; 30 min after an antimuscarinic drug was administered; an hour after the initial injection if a repeat dose was given at 30 min; and 4-hourly thereafter. Drug charts of all patients with death rattle were analysed to ascertain the amount of each drug given and the cost. The incidence of death rattle was 44% in phase I, and 36% in phase II. The percentage of patients with reduced noise scores 30 min after one injection of hyoscine was significantly greater than after one dose of glycopyrrolate (56% vs 27%, P = 0.002). The need for a second injection after 30 min was less using hyoscine (33% vs 50%, P = 0.03). There was no statistically significant difference in improvement at 1 h, or at the last recorded score before death. A comparison of the cost of drug treatment using hyoscine or glycopyrrolate was made, and the potential reduction in cost per patient in the glycopyrrolate group was largely offset by increased expenditure on other drugs, especially diamorphine, midazolam and levomepromazine. The results of this study suggest that: (1) glycopyrrolate 0.2 mg is less effective at reducing death rattle than hyoscine hydrobromide 0.4 mg when assessed at 30 min, (2) the use of glycopyrrolate may lead to an increased need for other sedative or anti-emetic medication such as diamorphine, midazolam or levomepromazine, and (3) the cost benefit of using glycopyrrolate over hyoscine hydrobromide is a small part of the total drug budget, and may be less than anticipated due to the increased need of these other drugs.

Development of a Visual Analogue Scale questionnaire for subjective assessment of salivary dysfunction

OBJECTIVE

This study's objective was to develop a Visual Analogue Scale (VAS) xerostomia questionnaire and to evaluate the validity and reliability for the clinical diagnosis of salivary gland dysfunction.

STUDY DESIGN

Thirty-six healthy adults participated in this double-blind, crossover study. Each subject received an antisialagogue (glycopyrrolate) or placebo. Unstimulated and stimulated parotid and submandibular saliva samples were collected 16 times over a period of 6 hours. An 8-item VAS xerostomia questionnaire was administered after each saliva collection.

RESULTS

The results demonstrated significant reliability for 7 of the 8 VAS items, whereas validity was significant for unstimulated submandibular saliva. Moving averages were calculated for VAS and salivary flow rate values, and significant correlations were observed between these factors, indicating that changes in VAS responses were predictive of changes in salivary flow.

CONCLUSIONS

These findings suggest that this VAS xerostomia questionnaire may be helpful in the diagnosis of salivary dysfunction and for detecting changes in salivary flow rate values over time.

Suicide and antidepressants

Suicidal thoughts and suicide attempts are an integral part of various depressions. Suicide attempts are common in major depression but even more common in recurrent brief depression, and the rate is further increased when these depressions occur comorbidly. Combined depression, where recurrent brief depression and major depression coexist, is the strongest clinical predictor of suicide attempts in the literature. There have been very few controlled studies of treatments for depression in high-risk groups of suicide attempters. Psychotherapy has been found to significantly raise the suicide attempt rate compared with conventional treatment, whereas fluoxetine and mianserin were not different from placebo. The only treatment that has been found to lower the suicide attempt rate in those with a history of previous suicide attempts is low doses of flupenthixol, a neuroleptic licensed for depression in Europe. This drug had a significant advantage compared with placebo in a six-month study. There are indications from large studies that maprotiline and amitriptyline might raise the suicide attempt rate, compared with placebo or other antidepressants, independent of their inherent toxicity in overdose. Several analyses of coroners' data show that tricyclic antidepressants are associated with high and unacceptable death rates in overdose compared with SSRIs and other safer antidepressants. Toxic antidepressants should be avoided in those thought to be at particular risk.

The use of anticholinergics in asthma

Anticholinergic medications have been accepted as an important treatment modality in chronic bronchitis and chronic asthma, but their use in acute asthma is more controversial. A brief historical context of anticholinergics is given. The innervations of the lung that govern bronchoconstriction and bronchodilatation are reviewed. The pharmacological and neurological properties of anticholinergics make them excellent modalities for treatment of asthma. The benefits of anticholinergics in acute asthma, exercise-induced asthma, nocturnal asthma, and psychogenic asthma are reviewed. The use of anticholinergics in anaphylaxis with beta-blockade is examined.

Preliminary study of glycopyrrolate in the management of drooling

OBJECTIVE

A study was undertaken to assess the efficacy of an oral anticholinergic drug, glycopyrrolate, in the management of drooling in children and young adults with disabilities.

METHODOLOGY

Glycopyrrolate was used by 24 children and young adults for up to 28 months. Parents/carers were asked to complete a questionnaire on the effects of the drug on severity and frequency of drooling and to report any side-effects.

RESULTS

Twenty-two questionnaires were returned. There was a statistically significant decrease in both severity and frequency of drooling with minimal side-effects reported.

CONCLUSION

In this preliminary study, glycopyrrolate was found to be an effective and well-tolerated addition to the management of drooling in children with disabilities.

The mydriatic effect of topical glycopyrrolate

BACKGROUND

Glycopyrrolate, an anticholinergic agent that does not cross the blood-brain barrier, has several indications, but its mydriatic effect has never been tested. This study was carried out in order to compare the mydriatic effect of glycopyrrolate 0.5% to that of atropine sulfate 1%.

METHODS

Glycopyrrolate 0.5% and atropine 1.0% were instilled separately in the eyes of albino rabbits. Pupil diameter and intra-ocular pressure were monitored.

RESULTS

Mydriasis was noted within 5 min of glycopyrrolate instillation, reached near-maximal level at 15 min and persisted for 1 week. Glycopyrrolate 0.5% showed a faster, stronger and more persistent mydriatic effect than atropine 1.0%. Administration of glycopyrrolate 0.5% solution b.i.d. for 1 week did not affect intra-ocular pressure or produce any adverse reaction.

CONCLUSION

Glycopyrrolate solution has the potential to deliver an ocular anticholinergic effect without causing associated central anticholinergic hazards.

Glycopyrrolate vs. atropine during anaesthesia for laryngoscopy and bronchoscopy

As glycopyrrolate has been reported superior to atropine with respect to reduction of salivation, stability of cardiac rate and rhythm, and recovery, a comparison of these properties of the two drugs and placebo was made in 45 patients undergoing direct laryngoscopy and 45 patients undergoing bronchoscopy, in most cases followed by mediastinoscopy. When given i.m. 30 min before anesthesia (midazolam, alfentanil, thiopentone, and suxamethonium), the two test drugs were found to be equally potent regarding the antisialogogic effect. The same increase in heart rate after the test drugs was seen before induction, and during anaesthesia heart rate rose to the same level in the placebo group as the test groups. During anaesthesia, blood pressure was lowest in the atropine group. No differences could be demonstrated with respect to cardiac arrhythmias, possibly due to the small size of the material. The present study gives no reason for preferring either drug, and only the efficacy of both test drugs in controlling airway secretions provides an argument for using any anticholinergic drug when laryngoscopy or bronchoscopy is performed under the conditions of the present study.

Comparison of aerosolized glycopyrrolate and metaproterenol in acute asthma

The efficacy of nebulized glycopyrrolate compared with metaproterenol was evaluated in 46 patients with acute asthma. In a double-blinded, randomized fashion, patients received, as sole therapy, either 2 mg of glycopyrrolate or 15 mg of metaproterenol every 2 h over a 6-h study period. Of the 35 patients completing the study, analysis of variance demonstrated no difference in percentage of change in FEV1 between glycopyrrolate and metaproterenol. Two hours after the initial dose, there was a 30 percent increase in FEV1 for glycopyrrolate compared with a 25 percent increase for metaproterenol (p greater than 0.05, NS). In contrast to the comparable bronchodilator activity, the side effects profile of the two agents were markedly dissimilar. Not only were subjective complaints of tremor, palpitations, and paresthesias increased for metaproterenol, but the heart rate response was significantly elevated (p less than 0.05) compared with glycopyrrolate. Based on these data, administration of the aerosolized anticholinergic agent, glycopyrrolate, is a reasonable therapeutic alternative for acute asthma.

Why do amitriptyline and dothiepin appear to be so dangerous in overdose?

Data from different analyses of reported deaths from overdose with antidepressants in the U.K. reveal that amitriptyline and dothiepin are the antidepressants most likely to be associated with death from overdose. All widely used tricyclic antidepressants (TCAs) except clomipramine and lofepramine appear to be dangerous in overdose, whereas the newer antidepressants such as mianserin, trazodone, viloxazine and the TCA lofepramine appear to be relatively safe. The toxicity of amitriptyline and dothiepin appears to be greater than all antidepressants including other TCAs and it is important to try to understand why. A number of explanations will be considered: 1. Dothiepin and amitriptyline may be inherently more toxic than other TCAs. 2. Dothiepin and amitriptyline may induce suicide more than other antidepressants. It is assumed that antidepressants are neutral with regard to inducing suicide but this may not be true. There is, for example, evidence that alprazolam and other benzodiazepines induce suicidal behaviour. 3. Amitriptyline and dothiepin are often presented in subtherapeutic and ineffective doses and it is possible that increased suicides may result from inadequately treated depression. 4. There may be a selective overreporting of deaths with amitriptyline and dothiepin. 5. Amitriptyline and prothiaden may be selectively given to the suicide prone on the mistaken assumption that they are safe.

Glycopyrrolate during ketamine/diazepam anaesthesia. A double-blind comparison with atropine

In a double-blind study, the effects of atropine and glycopyrrolate (dosage ratio 2:1) following i.m. and i.v. administration were compared with respect to salivation, heart rate, and blood pressure before, during and after i.v. infusion anaesthesia with ketamine and diazepam for alloplastic hip or knee surgery in 30 patients above the age of 50 years. Given with the premedicant, the two drugs were equally effective in reducing salivation. A slight increase in heart rate was seen after atropine only (P less than 0.005). Increases in heart rate and blood pressure during induction of anaesthesia were similar in the two groups. A second dose of the test drug was given with neostigmine for reversal of neuromuscular blockade. Again, there were no statistically significant differences with respect to salivation, blood pressure, heart rate, nausea and/or vomiting, unpleasant dreams and arousal time.

Integrated pharmacokinetics and pharmacodynamics of atropine in healthy humans. II: Pharmacodynamics

This study determined the kinetics of the effects of atropine on heart rate and saliva flow in three healthy male volunteers after intravenous administration of 1.35 and 2.15 mg of the drug. The pharmacokinetics of atropine and its primary metabolite, tropine, were determined simultaneously. Both the pharmacokinetic and effect data were fitted to an integrated kinetic-dynamic model. The maximum heart rate and minimum saliva flow occurred with a significant delay of 7-8 min after drug administration. Both effects were nonlinearly related to the amount of drug in the peripheral compartment. Maximum heart rates of 192 and 217% of the control values were observed at the lower and higher dose levels, respectively. Minimum saliva flows of 8 and 3% of the control values were measured after the lower and higher doses of atropine, respectively. The time durations of the positive chronotropic effect of the drug were 170 and 250 min at the lower and higher dose levels, respectively; the corresponding values for the length of the antisialogogue effect of the drug were 230 and 340 min, respectively.

The effects of atropine and glycopyrrolate on intra-ocular pressure in anaesthetised elderly patients

The effects of glycopyrrolate 0.2 mg and atropine 0.6 mg, given intravenously, were studied in 40 elderly patients undergoing intra-ocular surgery. Twenty patients had normal intra-ocular pressure (IOP) and 20 had raised IOP. The effects of each of the drugs on IOP, heart rate, prevention of the oculocardiac reflex and incidence of dysrhythmias were assessed. Anaesthesia with thiopentone, suxamethonium, nitrous oxide/oxygen, and halothane, using a semiclosed circle system resulted in a decrease in mean IOP in both the atropine and glycopyrrolate groups. Patients who had pre-existing raised IOP showed a significantly greater decrease in IOP than those with normal IOP. Patients with raised IOP who had received atropine experienced a greater decrease in IOP than those who had received glycopyrrolate. Both atropine and glycopyrrolate were effective in preventing the oculocardiac reflex. The increase in heart rate was greater in those patients who had received atropine. The incidence of dysrhythmias was low.

Comparison of some postanaesthetic effects of atropine and glycopyrrolate with particular emphasis on urinary problems

Two hundred and two patients undergoing elective surgery were given either atropine (98 patients) or glycopyrrolate (104 patients) for intravenous premedication and as an adjunct to reversal of neuromuscular block by neostigmine in a double-blind study. The dose ratio of atropine and glycopyrrolate was 2.5:1. After reversal, both drugs induced an initial increase and a subsequent decrease in heart rate. The mean values in % heart rate were statistically significantly higher in the glycopyrrolate group than in the atropine group. Semiquantitative measurement of salivation showed glycopyrrolate to be more potent as an antisialogogue drug. Nausea and vomiting were equally common after both drugs. There were no differences between the drugs in the occurrence of postoperative micturition difficulties, the total rate of this complication being 18%. It is concluded that factors other than the choice of anticholinergic drug may be blamed for postoperative micturition difficulties.

Glycopyrrolate: pharmacology and clinical use

This is a review of glycopyrrolate whose function in clinical practice is compared with that of atropine.

Dose-response studies on glycopyrrolate and atropine in conscious cardiac patients

The dose-heart rate response relationship for the two anticholinergics, atropine and glycopyrrolate, were studied in non-anaesthetised patients about to undergo coronary artery surgery. Two methods were used, the administration of increasing doses to different groups of patients, and an incremental dose technique in the same patient. Both drugs increased heart rate in a dose-related manner with glycopyrrolate being approximately twice as potent as atropine. Glycopyrrolate is as effective as atropine in correcting bradycardia prior to open heart surgery.

Lack of interaction between the tetracyclic antidepressant maprotiline and the centrally acting antihypertensive drug clonidine

The well known interaction between tricyclic antidepressants and the centrally acting antihypertensive drug clonidine, namely impairment of the antihypertensive effect of clonidine, is thought to be related to blockade of noradrenaline uptake or competition at central alpha-receptors. The tetracyclic antidepressant maprotiline has been shown to be a potent inhibitor of noradrenaline uptake and it might, therefore, interfere with the antihypertensive action of clonidine. The possible interaction of clonidine and maprotiline was studied in 8 healthy subjects using doses in the therapeutic range. The study followed a double-blind, cross over design, in which clonidine alone (0.3 mg p.o.), clonidine (0.3 mg p.o.) plus maprotiline (100 mg in 4 divided doses over 22 h), maprotiline alone (100 mg in 4 divided doses over 22 h) and placebo were given by the double-dummy technique. Several pharmacodynamic parameters were measured for 12 h after administration of the drugs (supine and erect blood pressure, heart rate, saliva production and sedation). Concurrent administration of maprotiline did not alter the effect of clonidine and neither the size nor the time of the maximal response after clonidine were influenced by maprotiline. It is concluded that [1] blockade of noradrenaline uptake is not associated with the interaction of tricyclic antidepressants and clonidine, and [2] maprotiline should be preferred to tricyclic antidepressants in hypertensive patients on clonidine therapy if a concomitant depressive illness has to be treated.

A comparison of atropine and glycopyrrolate in anaesthetic practice

The two anticholinergics, atropine and glycopyrrolate, were used for premedication and as an adjunct to reversal of residual neuromuscular block in a double-blind study. Glycopyrrolate, being about twice as potent as atropine in the clinical situation, was used in half the dosage of atropine. When used for premedication, no difference was found between the drugs concerning patients complaining of dry mouth, but more patients in the glycopyrrolate group had a gastric juice pH greater than 2.5 compared to the atropine group (not statistically different). The reversal mixture consisted of necostigmine 2.5 mg with either atropine 1 mg or glycopyrrolate 0.5 mg. The heart rate response between 2 and 10 min after injecting the reversal mixture was statistically significant (P ranged from 0.0001 to 0.05), the atropine group showing the most marked decrease: 18% in the atropine group had sinus bradycardia compared to 5% in the glycopyrrolate group: 34% in the atropine group exhibited arrhythmias compared to 10% in the glycopyrrolate group, the most common form being a nodal rhythm in both groups. More patients in the atropine group had "excessive" oropharyngeal secretions (more than 2 ml) when extubated (P less than 0.05). The postoperative assessment showed little difference in the two groups, apart from a lower incidence of nausea and vomiting in the atropine group (not statistically different). The study shows that the use of glycopyrrolate was associated with a more stable cardiovascular system, fewer arrhythmias and superior control of oropharyngeal secretions at the time of reversal.

Effects of intravenous administration of glycopyrrolate and atropine in anaesthetised patients

The effects of glycopyrrolate in doses of 5, 10 and 15 microgram/kg and atropine 10, 20 and 30 microgram/kg on heat rate and rhythm was studied in anesthetised patients. Both drugs produced a dose-related increase in heart rate. Glycopyrrolate was approximately twice as potent as atropine in increasing heart rate. The average time taken to achieve peak effect was 2-6 and 3-7 minutes for atropine and glycopyrrolate respectively, and this was significantly different. The smallest doses of both drugs were generally associated with supraventricular dysrhythmias, whereas these were mainly ventricular following the highest dose of both drugs.

Comparison of the effects of atropine and glycopyrrolate on various end-organs

Atropine and glycopyrrolate (glycopyrronium bromide), a quaternary ammonium drug, were evaluated in volunteers following intramuscular administration with respect to effects on various end-organs with cholinergic innervation. Glycopyrrolate appears to be five to six times more potent than atropine in its antisialogogue effect and also exhibits a selective, though prolonged, effect on salivary secretion and sweat gland activity. It has minimal cardiovascular, ocular and central nervous system effects.

Reversal of non-depolarising neuromuscular block in children: a comparison of atropine and glycopyrrolate in a mixture with neostigmine

Atropine and glycopyrrolate were compared when given in a mixture with neostigmine for the reversal of non-depolarising neuromuscular block in children. Glycopyrrolate was an effective antimuscarinic agent and could be safely used as an alternative to atropine, although the advantages in this age group were not as marked as have been observed in adults.

Intravenous administration of glycopyrronium: effects on cardiac rate and rhythm

Intravenous administration of glycopyrronium in doses up to 0.2 mg, was associated with minimal changes in cardiac rate and rhythm. Sinus arrhythmia, nodal rhythm and occasional atrial ectopics were the dysrhythmias observed. There were no accompanying changes in blood pressure.

Volume and pH of gastric contents following anticholinergic premedication

The effects of anticholinergic premedication with 1.0 mg atropine, 0.5 mg hyoscine and 0.2 mg glycopyrronium on volume and pH of gastric contents were studied and compared with a group receiving no anticholinergic premedication. The antisialogogue effects were also compared. Though the groups receiving atropine and glycopyrronium had the lowest mean aspirated volume and the highest mean pH respectively there was no essential difference between the various groups receiving anticholinergic premedication. However, the pH values were above 2.5 in the majority of these patients in comparison with the control group. The antisialogogue effects of the three anticholinergic drugs were similar.

Atropine versus glycopyrrolate. A study of intraocular pressure and pupil size in man

Following control observations of intraocular pressure and pupil size, in doses suitable for pre-anaesthetic medication, glycopyrrolate (0.004 mg/kg) and atropine (0.01 mg/kg) were given intramuscularly to healthy volunteers in a randomised, cross-over fashion. No significant change in either intraocular pressure or pupil size was noted 45 min after drug administration.