Pharmacokinetics and oral bioavailability of glycopyrrolate in children

Adverse Effects of Antidepressant Medications and their Management in Children and Adolescents

INTRODUCTION

Selective serotonin reuptake inhibitors (SSRIs) and, to a lesser extent, serotonin-norepinephrine reuptake inhibitors (SNRIs) are the cornerstone of pharmacotherapy for children and adolescents with anxiety and depressive disorders. These medications alleviate symptoms and restore function for many youths; however, they are associated with a distinct adverse effect profile, and their tolerability may complicate treatment or lead to discontinuation. Yet, SSRI/SNRI tolerability has received limited attention in the pediatric literature.

METHODS

This review examines the early- (e.g., activation, gastrointestinal symptoms, sedation) and late-emerging (e.g., weight gain) adverse effects of SSRIs and some SNRIs in pediatric patients.

RESULTS

We provide a framework for discussing SSRI/SNRI tolerability with patients and their families and describe the pharmacologic basis, course, and predictors of adverse events in youth. Strategies to address specific tolerability concerns are presented. For selected adverse events, using posterior simulation of mean differences over time, we describe their course based on Physical Symptom Checklist measures in a prospective, randomized trial of anxious youth aged 7-17 years who were treated with sertraline (n = 139) or placebo (n = 76) for 12 weeks in the Child/Adolescent Anxiety Multimodal Study (CAMS).

MAIN RESULTS

In CAMS, the relative severity/burden of total physical symptoms (p < 0.001), insomnia (p = 0.001), restlessness (p < 0.001), nausea (p = 0.002), abdominal pain (p < 0.001), and dry mouth (p = 0.024) decreased from baseline over 12 weeks of sertraline treatment, raising the possibility that these symptoms are transient. No significant changes were observed for sweating (p = 0.103), constipation (p = 0.241), or diarrhea (p = 0.489). Finally, we review the antidepressant withdrawal syndrome in children and adolescents and provide guidance for SSRI discontinuation, using pediatric pharmacokinetic models of escitalopram and sertraline-two of the most used SSRIs in youth.

CONCLUSION

SSRI/SNRIs are associated with both early-emerging (often transient) and late-emerging adverse effects in youth. Pharmacokinetically-informed appraoches may address some adverse effects and inform SSRI/SNRI discontinuation strategies.

Pharmacology, toxicology and clinical safety of glycopyrrolate

The clinical use of the anticholinergic glycopyrrolate dates back to the early 1960s when it was first approved in the U.S. Since then, oral and inhalation formulations have been developed as therapeutic agents inhibiting the muscarinic acetylcholine receptor in various indications including chronic obstructive pulmonary disease (COPD), excessive salivation, and peptic ulcers. More recently, topical formulations of glycopyrrolate (GPB, also known as glycopyrronium bromide) have gained interest as a treatment option for excessive sweating (hyperhidrosis). The U.S. Food and Drug Administration (FDA) approved the first topical glycopyrronium product for the treatment of hyperhidrosis in 2018. Glycopyrrolate, as a quaternary amine, shows minimal penetration of the blood brain barrier which limits CNS side effects. In addition, lack of phototoxicity, genotoxicity and carcinogenicity makes it suitable for chronic indications. The information on the nonclinical and clinical safety profile of glycopyrronium supporting various therapeutically approved uses has been obtained from published literature, our own data as well as summary documents issued by regulatory bodies. Collectively, these data support the conclusion that the benefits of glycopyrronium generally outweigh the risks in chronic use indications that require muscarinic receptor antagonism to provide therapeutic effects.

Glycopyrronium tosylate in pediatric primary axillary hyperhidrosis: Post hoc analysis of efficacy and safety findings by age from two phase three randomized controlled trials

OBJECTIVES

Hyperhidrosis in pediatric patients has been understudied. Post hoc analyses of two phase 3 randomized, vehicle-controlled, 4-week trials (ATMOS-1 [NCT02530281] and ATMOS-2 [NCT02530294]) were performed to assess efficacy and safety of topical anticholinergic glycopyrronium tosylate (GT) in pediatric patients.

METHODS

Patients had primary axillary hyperhidrosis ≥ 6 months, average Axillary Sweating Daily Diary (ASDD/ASDD-Children [ASDD-C]) Item 2 (sweating severity) score ≥ 4, sweat production ≥ 50 mg/5 min (each axilla), and Hyperhidrosis Disease Severity Scale (HDSS) ≥ 3. Coprimary end points were ≥ 4-point improvement on ASDD/ASDD-C Item 2 (a validated patient-reported outcome) and change in gravimetrically measured sweat production at Week 4. Efficacy and safety data are shown through Week 4 for the pediatric (≥ 9 to ≤ 16 years) vs older (> 16 years) subgroups.

RESULTS

Six hundred and ninety-seven patients were randomized in ATMOS-1/ATMOS-2 (GT, N = 463; vehicle, N = 234); 44 were ≥ 9 to ≤ 16 years (GT, n = 25; vehicle, n = 19). Baseline disease characteristics were generally similar across subgroups. GT-treated pediatric vs older patients had comparable improvements in ASDD/ASDD-C Item 2 (sweating severity) responder rate, HDSS responder rate (≥ 2-grade improvement]), sweat production, and quality of life (mean change from Baseline in Dermatology Life Quality Index [DLQI]/children's DLQI), with greater improvement vs vehicle. Treatment-emergent adverse events were similar between subgroups, and most were mild, transient, and infrequently led to discontinuation.

CONCLUSIONS

Topical, once-daily GT improved disease severity (ASDD/ASDD-C, HDSS), sweat production, and quality of life (DLQI), with similar findings in children, adults, and the pooled population. GT was well tolerated, and treatment-emergent adverse events were qualitatively similar between subgroups and consistent with other anticholinergics.

A case report: Glycopyrrolate for treatment of exercise-induced hyperhidrosis

Objective:

Hyperhidrosis can cause dehydration and exercise intolerance. There are several case reports of extremely high sweat rates in athletes. We present as case report of a 17-year-old male with the highest sweat rate recorded in the literature (5.8 L/h). Our goal was to determine if glycopyrrolate, an anticholinergic medication with primarily anti-muscarinic effects that is known to decrease sweat production, would reduce the sweat rate of our subject in a controlled exercise setting.

Methods:

Our patient and a control subject were subjected to an exercise protocol consisting of running on a treadmill (5.4–6.7 mile/h at 1° of incline) in a warm climate-controlled chamber after receiving 0, 2, or 4 mg of glycopyrrolate. Core temperature, heart rate, rater of perceived exertion, and sweat rate were monitored in both subjects.

Results:

Glycopyrrolate dose was not significantly correlated with decreased sweat rate and maximal core temperature. However, the clinical effect of reducing the sweat rate was very strong. The improvement of the subject’s sweat rate allowed him to successfully return to sport.

Conclusion:

Our findings suggest that low-dose glycopyrrolate may be a safe and effective method of controlling exertional hyperhidrosis.

Case report of successful treatment of pallid breath-holding spells with glycopyrrolate

Breath-holding spells are a common childhood disorder that typically present before 12 months of age. Whereas most cases are benign, some patients have very severe cases associated with bradycardia that can progress from asystole to syncope and seizures. Treatment studies have implicated the use of several therapies, such as oral iron, fluoxetine, and pacemaker implantation. This is a retrospective study of patients treated with glycopyrrolate for pallid breath-holding spells. Clinical data from 4 patients referred to pediatric cardiology who saw therapeutic benefit from treatment using glycopyrrolate were reviewed to evaluate for clinical response to the drug. Two twin patients, whose symptoms began at 5 months of age, experienced a decrease in breath-holding frequency after 1 month. A patient diagnosed at 7 months of age experienced a decrease in frequency of spells. A patient diagnosed at 10 months of age reported cessation of syncope shortly after initiation of glycopyrrolate and complete resolution of breath-holding spells during prolonged treatment. This case study of 4 patients with pallid breath-holding offers evidence that glycopyrrolate may be beneficial in treating breath-holding spells and has a safer side-effect profile than pacemaker implantation.

Iontophoretic and microneedle mediated transdermal delivery of glycopyrrolate

Purpose: The objective of this study was to investigate the use of iontophoresis, soluble microneedles and their combination for the transdermal delivery of glycopyrrolate. Methods: In vitro permeation was tested using full thickness porcine ear skin mounted onto Franz diffusion cells. Iontophoresis (0.5 mA/cm²) was done for 4 h using Ag/AgCl electrodes. For microneedles, three line array (27 needles/line) of maltose microneedles were used to microporate the skin prior to mounting. Pore uniformity was determined by taking fluorescent images of distribution of calcein into pores and processing the images using an image analysis tool, which measured the fluorescent intensity in and around each pore to provide a pore permeability index (PPI). The donor chamber contained 500 µL of a 1 mg/mL solution of glycopyrrolate, and the receptor chamber contained 5 mL of 50 mM NaCl in deionized water. Samples were collected at predetermined time points over a period of 24 h and analyzed by HPLC. Skin irritation testing was performed with a 3D cell culture kit of human skin. MTT assay determined cell viability; viability less than 50% was considered irritant. Results: A control experiment which investigated passive permeation of glycopyrrolate delivered an average cumulative amount of 24.92 ± 1.77 µg/cm² at 24 h, while microneedle pretreatment increased permeability to 46.54 ± 6.9 µg/cm². Both iontophoresis (158.53 ± 17.50 µg/cm²) and a combination of iontophoresis and microneedles (182.43 ± 20.06 µg/ cm²) significantly increased delivery compared to passive and microneedles alone. Glycopyrrolate solution was found to be nonirritant with cell viability of 70.4% ± 5.03%. Conclusion: Iontophoresis and a combination of iontophoresis with microneedle pretreatment can be effectively used to enhance the transdermal delivery of glycopyrrolate. Glycopyrrolate was found to be non-irritant to skin.

Determination of the pharmacokinetics of glycopyrronium in the lung using a population pharmacokinetic modelling approach

AIMS

Glycopyrronium bromide (NVA237) is a once-daily long-acting muscarinic antagonist recently approved for the treatment of chronic obstructive pulmonary disease. In this study, we used population pharmacokinetic (PK) modelling to provide insights into the impact of the lung PK of glycopyrronium on its systemic PK profile and, in turn, to understand the impact of lung bioavailability and residence time on the choice of dosage regimen.

METHODS

We developed and validated a population PK model to characterize the lung absorption of glycopyrronium using plasma PK data derived from studies in which this drug was administered by different routes to healthy volunteers. The model was also used to carry out simulations of once-daily and twice-daily regimens and to characterize amounts of glycopyrronium in systemic compartments and lungs.

RESULTS

The model-derived PK parameters were comparable to those obtained with noncompartmental analysis, confirming the usefulness of our model. The model suggested that the lung absorption of glycopyrronium was dominated by slow-phase absorption with a half-life of about 3.5 days, which accounted for 79% of drug absorbed through the lungs into the bloodstream, from where glycopyrronium was quickly eliminated. Simulations of once-daily and twice-daily administration generated similar PK profiles in the lung compartments.

CONCLUSIONS

The slow absorption from the lungs, together with the rapid elimination from the systemic circulation, could explain how once-daily glycopyrronium provides sustained bronchodilatation with a low incidence of adverse effects in patients with chronic obstructive pulmonary disease. Its extended intrapulmonary residence time also provides pharmacokinetic evidence that glycopyrronium has the profile of a once-daily drug.

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.

Safety and efficacy of glycopyrrolate oral solution for management of pathologic drooling in pediatric patients with cerebral palsy and other neurologic conditions

Background

The purpose of this study was to assess the safety and efficacy of oral glycopyrrolate solution 1 mg/5 mL for 24 weeks in pediatric patients with chronic moderate-to- severe drooling associated with cerebral palsy and other neurologic conditions.

Methods

In this multicenter, open-label, 24-week study, males and females aged 3–18 years weighing at least 27 lb received oral glycopyrrolate solution, starting at 0.02 mg/kg three times daily and titrated in increments of 0.02 mg/kg every 5–7 days for 4 weeks to an optimal maintenance dose or a maximum dose of 0.1 mg/kg, but not exceeding 3 mg three times daily. Safety was assessed by description and tabulation of all adverse events. The primary efficacy endpoint was response, defined as at least a three-point change from baseline to week 24 on the modified Teacher’s Drooling Scale.

Results

Of 137 intent-to-treat participants, 10 (7.3%) received the maximum dose of 0.1 mg/kg three times daily; 122 (89%) had at least one treatment-emergent adverse event, 47% related to oral glycopyrrolate solution, with most being mild-to-moderate in intensity. The most commonly reported treatment-emergent adverse events were constipation (20.4%), vomiting (17.5%), diarrhea (17.5%), pyrexia (14.6%), dry mouth (10.9%), flushing (10.9%), and nasal congestion (10.9%). Nineteen patients (13.9%) discontinued treatment due to an adverse event, but no adverse event was specifically associated with discontinuation. Two patients had clinically significant toxicity grade shifts, one each in platelet count and calcium concentration. No deaths occurred on treatment; deaths of three patients (multisystem organ failure, anoxic encephalopathy, and aspiration pneumonia) within 30 days of their last dose were not considered to be treatment-related. At 24 weeks, 52.3% (95% confidence interval 43.7–60.9) of patients were responders, with at least a three-point decrease in modified Teacher’s Drooling Scale from baseline, with 83.5% of parents/caregivers and 85.8% of investigators rating oral glycopyrrolate solution as being worthwhile.

Conclusion

Oral glycopyrrolate solution 1 mg/5 mL for chronic moderate-to-severe drooling associated with cerebral palsy or other neurologic conditions was well tolerated over 24 weeks by pediatric patients aged 3–18 years.

Randomized Phase III evaluation of the efficacy and safety of a novel glycopyrrolate oral solution for the management of chronic severe drooling in children with cerebral palsy or other neurologic conditions

AIM

To evaluate the efficacy of glycopyrrolate oral solution (1 mg/5 mL) in managing problem drooling associated with cerebral palsy and other neurologic conditions.

METHOD

Thirty-eight patients aged 3-23 years weighing at least 27 lb (12.2 kg) with severe drooling (clothing damp 5-7 days/week) were randomized to glycopyrrolate (n = 20), 0.02-0.1 mg/kg three times a day, or matching placebo (n = 18). Primary efficacy endpoint was responder rate, defined as percentage showing ≥3-point change on the modified Teacher's Drooling Scale (mTDS).

RESULTS

Responder rate was significantly higher for the glycopyrrolate (14/19; 73.7%) than for the placebo (3/17; 17.6%) group (P = 0.0011), with improvements starting 2 weeks after treatment initiation. Mean improvements in mTDS at week 8 were significantly greater in the glycopyrrolate than in the placebo group (3.94 ± 1.95 vs 0.71 ± 2.14 points; P < 0.0001). In addition, 84% of physicians and 100% of parents/caregivers regarded glycopyrrolate as worthwhile compared with 41% and 56%, respectively, for placebo (P ≤ 0.014). Most frequently reported treatment-emergent adverse events (glycopyrrolate vs placebo) were dry mouth, constipation, and vomiting.

INTERPRETATION

Children aged 3-16 years with problem drooling due to neurologic conditions showed a significantly better response, as assessed by mTDS, to glycopyrrolate than to placebo. CLINICALTRIALS.GOV IDENTIFIER: NCT00425087.