The comparative safety of oral versus intranasal desmopressin for the treatment of children with nocturnal enuresis

Central diabetes insipidus from a patient's perspective: management, psychological co-morbidities, and renaming of the condition: results from an international web-based survey

BACKGROUND

Central diabetes insipidus is a rare neuroendocrine condition. Data on treatment-associated side-effects, psychological comorbidities, and incorrect management are scarce. The aim of this study was to investigate patients' perspectives on their disease.

METHODS

This study used a cross-sectional, web-based, anonymous survey, developed by endocrinologists and patient representatives, to collect the opinions of patients with central diabetes insipidus on management and complications of their disease, psychological comorbidities, degree of knowledge and awareness of the condition among health-care professionals, and renaming the disease to avoid confusion with diabetes mellitus (diabetes).

FINDINGS

Between Aug 23, 2021, and Feb 7, 2022, 1034 patients with central diabetes insipidus participated in the survey. 91 (9%) participants were children and adolescents (37 [41%] girls and 54 [59%] boys; median age 10 years [IQR 6-15]) and 943 (91%) were adults (757 [80%] women and 186 [20%] men]; median age 44 years [34-54]). 488 (47%) participants had isolated posterior pituitary dysfunction and 546 (53%) had combined anterior and posterior pituitary dysfunction. Main aetiologies were idiopathic (315 [30%] of 1034 participants) and tumours and cysts (pre-surgical 217 [21%]; post-surgical 254 [25%]). 260 (26%; 95% CI [0·23-0·29]) of 994 patients on desmopressin therapy had hyponatraemia leading to hospitalisation. Patients who routinely omitted or delayed desmopressin to allow intermittent aquaresis had a significantly lower prevalence of hyponatraemia compared with those not aware of this approach (odds ratio 0·55 [95% CI 0·39-0·77]; p=0·0006). Of patients who had to be hospitalised for any medical reason, 71 (13%; 95% CI 0·10-0·16) of 535 patients did not receive desmopressin while in a fasting state (nil by mouth) without intravenous fluid replacement and reported symptoms of dehydration. 660 (64%; 0·61-0·67) participants reported lower quality of life, and 369 (36%; 0·33-0·39) had psychological changes subjectively associated with their central diabetes insipidus. 823 (80%; 0·77-0·82) participants encountered a situation where central diabetes insipidus was confused with diabetes mellitus (diabetes) by health-care professionals. 884 (85%; 0·83-0·88) participants supported renaming the disease; the most favoured alternative names were vasopressin deficiency and arginine vasopressin deficiency.

INTERPRETATION

This is the largest survey of patients with central diabetes insipidus, reporting a high prevalence of treatment-associated side-effects, mismanagement during hospitalisation, psychological comorbidities, and a clear support for renaming the disease. Our data are the first to indicate the value of routinely omitting or delaying desmopressin.

FUNDING

Swiss National Science Foundation, Swiss Academy of Medical Sciences, and G&J Bangerter-Rhyner-Foundation.

Serum Sodium Alterations in Children with Primary Monosymptomatic Nocturnal Enuresis Using Desmopressin

Background: Hyponatremia/water intoxication has been considered a rare but serious complication of desmopressin (DDAVP) for the treatment of primary monosymptomatic nocturnal enuresis (PMNE). Objectives: This study aimed to identify the incidence and risk factors of serum sodium (Na) alterations in children with PMNE treated with oral or intranasal DDAVP. Methods: A total of 201 patients with PMNE were evaluated in 2 groups using intranasal (n = 127) or oral DDAVP (n = 74) for approximately 6 months. Treatment efficacy was defined as a more than 50% decrease in wet nights after 1 month of treatment. Serum Na was measured before, during, and after treatment in all patients. Predisposing factors of serum Na disturbance were evaluated concomitantly. Results: The mean age of patients was 8.8 ± 2.6 (5 - 17.5) years, and males outnumbered females (M/F = 1.68). Treatment efficacy was 100% in 93 (46.2%), and > 90% in 157 (78.1%) cases. Oral DDAVP had significantly more therapeutic effects than intranasal treatment (P = 0.024). However, serum Na had no significant difference between the 2 groups (P = 0.52). Hyponatremia occurred in 7 (3.5%) patients (3 in oral treatment and 4 in intranasal treatment; P = 0.73) with no significant correlation to age, gender, body weight, frequency of enuresis, and initial serum Na. However, decreased serum Na > 5 mEq/L was a significant risk factor for the prediction of hyponatremia in our patients (P < 0.001). Conclusions: Oral DDAVP had more therapeutic effects than intranasal treatment for the treatment of PMNE. Serum Na had no significant alteration in both oral and intranasal treatments, and hyponatremia was a rare complication of DDAVP, which occurred significantly in children with a > 5-mEq/L decrease of initial serum Na concentration. As a suggestion, monitoring serum Na is not an essential follow-up in asymptomatic patients in DDAVP treatment.

Vasopressin and Its Analogues: From Natural Hormones to Multitasking Peptides

Human neurohormone vasopressin (AVP) is synthesized in overlapping regions in the hypothalamus. It is mainly known for its vasoconstricting abilities, and it is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Over years, many attempts have been made to modify this hormone and find AVP analogues with different pharmacological profiles that could overcome its limitations. Non-peptide AVP analogues with low molecular weight presented good affinity to AVP receptors. Natural peptide counterparts, found in animals, are successfully applied as therapeutics; for instance, lypressin used in treatment of diabetes insipidus. Synthetic peptide analogues compensate for the shortcomings of AVP. Desmopressin is more resistant to proteolysis and presents mainly antidiuretic effects, while terlipressin is a long-acting AVP analogue and a drug recommended in the treatment of varicose bleeding in patients with liver cirrhosis. Recently published results on diverse applications of AVP analogues in medicinal practice, including potential lypressin, terlipressin and ornipressin in the treatment of SARS-CoV-2, are discussed.

Desmopressin therapy in children and adults: pharmacological considerations and clinical implications

PURPOSE

This review aims to provide prescribing clinicians a deeper appreciation of desmopressin's clinical indications and formulation types, to better balance efficacy and safety through proper formulation selection.

BACKGROUND

Since its discovery 50 years ago, desmopressin's antidiuretic properties have been used for central diabetes insipidus, primary monosymptomatic nocturnal enuresis and adult nocturnal polyuria, while its coagulant effects are useful for mild hemophilia A and von Willebrand Disease. During this time, newer formulations of desmopressin have also been introduced to the market raising questions on interchangeability, dose conversion and safety. The wide array of clinical indications and variable pharmacokinetic properties of different desmopressin preparations raises the possibility of medication error, especially the risk of hyponatraemia.

METHODOLOGY

A narrative review to explore clinically relevant aspects of desmopressin therapy, synthesising information obtained from searches of published literature.

RESULTS

We identified that the risk factors for developing hyponatremia include extremes of age, existing comorbidity, drug interaction, intranasal formulations and intercurrent illness. We describe the dose equivalence between all formulations to facilitate conversion. We highlight that in view of inter-subject variability, close monitoring is recommended when switching preparations. We found that paediatric data remains limited, leading to recent proposals for age- and weight-based dosing regimens.

CONCLUSION

The risk of hyponatremia, albeit small, can be reduced by adhering to the indication-specific doses and taking steps to govern the safe prescription of the drug. Further paediatric clinical trials are awaited to expand the evidence base of childhood desmopressin therapy.

Treatment strategies for clozapine-induced nocturnal enuresis and urinary incontinence: a systematic review

BACKGROUND

Clozapine is the most effective medication for treatment-refractory schizophrenia but is associated with significant adverse drug reactions, including nocturnal enuresis and urinary incontinence. This side effect can be burdensome and lead to medication nonadherence and psychotic relapse. Evidence to guide treatment of clozapine-induced nocturnal enuresis and urinary incontinence is sparse. We therefore aimed to synthesize the evidence base to guide management for clinicians, patients, and their carers.

METHODS

We systematically searched PubMed, Embase, PsycInfo, CINAHL, and the Cochrane Trial Registry databases from inception to May 2021 for publications on management of clozapine-induced nocturnal enuresis and urinary incontinence using a PROSPERO preregistered search strategy.

RESULTS

We identified 22 case reports and case series describing 74 patients. Interventions included clozapine dose reduction, nonpharmacological treatment, and pharmacological treatments. Among pharmacological treatments, desmopressin, oxybutynin, trihexyphenidyl, tolterodine, imipramine, amitriptyline, ephedrine, pseudoephedrine, aripiprazole, and verapamil were associated with complete resolution of nocturnal enuresis and urinary incontinence. Balancing evidence for effectiveness against risk of adverse effects, we developed a management framework for clozapine-induced nocturnal enuresis and urinary incontinence.

CONCLUSIONS

Following assessment of urological, psychiatric, pharmacological, and common comorbid medical issues, first-line treatments should be nonpharmacological, including bathroom alarms, voiding before bedtime, and nocturnal fluid restriction. If these interventions do not provide adequate relief, aripiprazole should be trialed. Desmopressin may be considered for severe refractory cases, but monitoring for hyponatremia is essential.

Desmopressin versus desmopressin + oxybutynin in the treatment of children with nocturnal enuresis

INTRODUCTION

Enuresis is identified as voluntary or involuntary leakage of urine for at least three consecutive months in the daytime and/or nighttime on clothes for children older than five. Monosymptomatic nocturnal enuresis (MNE) describes nighttime wetting without daytime leakage of urine in children with no pathology in the urinary system and it is 80% more common than enuresis. Desmopressin is the most common medical treatment for MNE. The aim of this study is to retrospectively compare the effectiveness of desmopressin as monotherapy and desmopressin + oxybutynin as a combination therapy in the treatment of nocturnal enuresis.

MATERIAL AND METHOD

This study retrospectively evaluated 183 patients who applied to pediatrics, pediatrics surgery and urology clinics with the complaint of nocturnal enuresis and diagnosed with primary monosymptomatic nocturnal enuresis between January 2014 and December 2019. The patients were divided into two groups (91 patients) who only received desmopressin therapy (Group 1), and those (92 patients) who received desmopressin and oxybutynin combination therapy (Group 2). Response to treatment, compliance and recurrence ratios were determined in the evaluation. Complete response was accepted as 90-100% decrease in the number of nighttime wetting, partial response was accepted as 50-90% decrease in the number of nighttime wetting and those below 50% were regarded as non-response. The 1st, 3rd, and 6th months of control data of treatment effectiveness of both groups were evaluated and their responses to treatment and the side effects of drugs were examined.

RESULTS

The mean age 183 patients of whom 103 were male and 80 were female was 10 (6-16) year. In the first month of control of Group 1, 71.4% had a complete cure, 8.8% had a partial cure and 19.8% had no response to treatment. In the third month of control of Group 1, 74.73% gave a complete response and were cured, 5.5% gave a partial response and 19.78% had no response. In the sixth month of Group 1, 70 patients were evaluated as complete response (79.5%), and 5 patients were evaluated as partial response (5.6%). In the first month of control of Group 2, 75% gave a complete response, 10.9% gave a partial response, 14.1% had no response to treatment. In the third month of control of Group 2, 86.9% gave a complete response, 6.52% gave a partial response, and 6.52% had no response. In the sixth month of the control of Group 2, the number of patients who did not come for control and could not be reached was 2, 83 patients out of 90 patients were evaluated as complete response (92.2%), 6 patients were evaluated as partial response (6.6%).

CONCLUSION

Desmopressin is the only FDA approved pharmacologic treatment for nocturnal enuresis. Desmopressin reduces urine production and the anticholinergic agent allows the bladder to store more urine. Therefore, combined therapy can be recommended in the MNE treatment for specially selected cases.

Experimental Design Based Optimization and Ex Vivo Permeation of Desmopressin Acetate Loaded Elastic Liposomes Using Rat Skin

The study aimed to develop elastic-liposome-based transdermal delivery of desmopressin acetate for enhanced permeation to control enuresis, central diabetes insipidus, and traumatic injury. Elastic liposomes (ELs)-loaded desmopressin acetate was prepared, optimized, and evaluated for improved transdermal permeation profiles using rat skin. Full factorial design with independent factors (X₁ for lipid and X₂ for surfactant) at three levels was used against four responses (Y₁, Y₂, Y₃, and Y₄) (dependent variables). Formulations were characterized for vesicle size, polydispersity index (PDI), zeta potential, % entrapment efficiency (% EE), in vitro drug release, in vitro hemolysis potential, ex vivo drug permeation and drug deposition (DD), and ex vivo vesicle–skin interaction using scanning electron microscopy studies. The optimized formulation ODEL1 based on desirability function was found to have vesicle size, % EE, % DR, and permeation flux values of 118.7 nm, 78.9%, 75.1%, and 5.3 µg/h·cm², respectively, which were close to predicted values. In vitro release profiles indicated slow and sustained delivery. Permeation flux values of ODEL1 and ODEL2 were 5.3 and 3.1 µg/h·cm², respectively, which are 7.5- and 4.4-fold higher as compared to DS (0.71 µg/h·cm²). The obtained flux was relatively higher than the clinical target value of the drug for therapeutic efficacy. Moreover, the DD value of ODEL1 was significantly higher than ODEL2 and DS. Hemocompatibility study confirmed safety concerns. Finally, vesicle–skin interaction corroborated mechanistic views of permeation through rat skin. Conclusively, the transdermal delivery may be a suitable alternative to oral and nasal delivery to treat nocturnal enuresis, central diabetes insipidus, hemophilia A and von Willebrand’s disease, and any traumatic injuries.

Changes in prescribing trends and initial pharmacotherapy of children with nocturnal enuresis in Japan: a large-scale medical claims database analysis

PURPOSE

We analyzed the annual trends in and initial choice of pharmacotherapy for children with nocturnal enuresis (NE) using a large-scale medical claims database in Japan.

METHODS

A retrospective descriptive study performed using data from the Japan Medical Data Center between January 2005 and March 2019 involving 23,814 registrants under 16 years of age. In the first cohort of children with NE, we analyzed the comorbidities and associated annual pharmacotherapy prescribing trends. In the second cohort of only newly diagnosed cases, we analyzed the first prescribed age and initial choice of pharmacotherapy.

RESULTS

A total of 3494 children with NE were identified (mean age, 5.1 ± 3.6 years; male, 66.0%). An incremental increase in the proportion of children administered NE medications was observed. The proportion of children treated with desmopressin significantly increased, whereas the prescription of tricyclic antidepressants significantly decreased and that of anticholinergics did not significantly change. Among the newly diagnosed children, 1897 were treated with approximately 90% of the prescribed monotherapy. Sublingual desmopressin monotherapy accounts for more than half of the initial pharmacotherapy from 2016 onward. Regardless of the drug class, pharmacological therapy was commonly initiated at the age of 8.3 ± 2.1 years.

CONCLUSIONS

In Japan, the proportion of children treated with pharmacotherapy has been increasing. Furthermore, since the introduction of desmopressin sublingual formulations in 2012, a paradigm shift has occurred and this form of medication is now the most commonly prescribed, both from the annual perspective and as an initial choice among the newly diagnosed.

Pediatric Pharmacology of Desmopressin in Children with Enuresis: A Comprehensive Review

Desmopressin is a synthetic analogue of the natural antidiuretic hormone arginine vasopressin. Over the years, it has been clinically used to manage nocturnal polyuria in children with enuresis. Various pharmaceutical formulations of desmopressin have been commercialized for this indication-nasal spray, nasal drops, oral tablet and oral lyophilizate. Despite the fact that desmopressin is a frequently prescribed drug in children, its use and posology is based on limited pediatric data. This review provides an overview of the current pediatric pharmacological data related to the different desmopressin formulations, including their pharmacokinetics, pharmacodynamics and adverse events. Regarding the pharmacokinetics, a profound food effect on the oral bioavailability was demonstrated as well as different plasma concentration-time profiles (double absorption peak) of the desmopressin lyophilizate between adults and children. Literature about maturational differences in distribution, metabolism and excretion of desmopressin is rather limited. Regarding the pharmacodynamics, formulation/dose/food effect and predictors of response were evaluated. The lyophilizate is the preferred formulation, but the claimed bioequivalence in adults (200 µg tablet and 120 µg lyophilizate), could not be readily extrapolated to children. Prescribing the standard flat-dose regimen to the entire pediatric population might be insufficient to attain response to desmopressin treatment, whereby dosing schemes based on age and weight were proposed. Moreover, response to desmopressin is variable, whereby complete-, partial- and non-responders are reported. Different reasons were enumerated that might explain the difference in response rate to desmopressin observed: different pathophysiological mechanisms, bladder capacity and other predictive factors (i.e. breast feeding, familial history, compliance, sex, etc.). Also, the relapse rate of desmopressin treatment was high, rendering it necessary to use a pragmatic approach for the treatment of enuresis, whereby careful consideration of the position of desmopressin within this treatment is required. Regarding the safety of the different desmopressin formulations, the use of desmopressin was generally considered safe, but additional measures should be taken to prevent severe hyponatremia. To conclude the review, to date, major knowledge gaps in pediatric pharmacological aspects of the different desmopressin formulations still remain. Additional information should be collected about the clinical relevance of the double absorption peak, the food effect, the bioequivalence/therapeutic equivalence, the pediatric adapted dosing regimens, the study endpoints and the difference between performing studies at daytime or at nighttime. To fill in these gaps, additional well designed pharmacokinetic and pharmacodynamic studies in children should be performed.

Alarm therapy and desmopressin in the treatment of patients with nocturnal enuresis

PURPOSE

The purpose of this study was to compare the rates of success, relapse, and compliance to treatment in patients undergoing alarm therapy or receiving desmopressin for primary monosymptomatic nocturnal enuresis (PMNE).

MATERIALS AND METHODS

This retrospective study was performed by reviewing the medical files of patients undergoing alarm therapy (Group 1) or receiving desmopressin (Group 2) for PMNE, between January 2010 and July 2014. Patients undergoing treatment in the 3^rd and 6^th month as well as 1^st year follow-up data were analyzed. Two groups were compared with regard to treatment success, relapse rate, and compliance to treatment.

RESULTS

Group 1 included 64 and Group 2 included 70 children. Relapse rates at the 3^rd month, 6^th month, and 1^st year were 67.2%, 71.9%, and 17.0% for Group 1 and 74.3%, 80.0%, and 21.4% for Group 2, respectively. There was no statistically significant difference between relapse rates at any point of follow-up.

CONCLUSIONS

Alarm therapy and desmopressin have the same success rate and relapse rates for PMNE. Compliance with alarm therapy is higher and we recommend it as the first-line treatment. On the other hand, desmopressin has low side effects and can also be used.

Desmopressin-Induced Severe Hyponatremia with Central Pontine Myelinolysis: A Case Report

Desmopressin, a synthetic vasopressin analog, is used to treat central diabetes insipidus, hemostatic disorders such as von Willebrand’s disease, and nocturnal enuresis. We present the case of a 69-year-old man who developed severe hyponatremia during treatment with intranasal desmopressin at 10 µg twice daily for chronic polyuria and nocturia thought to be due to central diabetes insipidus. After 5 months of therapy, the patient noticed progressive fatigue, anorexia, dizziness, weakness, light-headedness, decreased concentration, and new-onset falls. At 6 months of therapy, the patient was brought to the emergency department for altered mental status and was found to be severely hyponatremic with a serum sodium level of 96 mmol/L, down from a value of 134 mmol/L at the initiation of therapy. The intranasal desmopressin was discontinued and the patient was admitted to the intensive care unit where the hyponatremia was slowly corrected over the next week to 132 mmol/L, never increasing by more than 8 mmol/L a day, with careful fluid management. This included infusion of over 11 L of 5% dextrose to account for a high urine output, which peaked at 7.4 L in 1 day. However, while the recommended rate for sodium correction was followed, the patient’s magnetic resonance imaging of the brain obtained after discharge displayed evidence of central pontine myelinolysis. Despite this finding, the patient eventually returned to his baseline mental status with no permanent neurologic deficits.

Oral Desmopressin Lyophilisate Formulation (MELT): Efficacy and Safety in Children and Adults

Nocturnal enuresis (NE) is a common disorder in childhood and desmopressin is one of the most widely and well-tolerated medications for NE. The recent oral lyophilisate formulation of desmopressin (MELT) is effective in the treatment of NE in children and nocturia in adults. A MEDLINE literature search MEDLINE (2000-July 2017) was performed using the search terms MELT enuresis, MELT desmopressin, sublingual desmopressin, lyophilisate desmopressin. Twenty articles were analyzed with a number of patients of 3448. In 12 articles were reported 1275 pediatric patients (<18 years old), and in 8 articles 2213 adult patients. In pediatric population the indication was enuresis in 1269 patients and central diabetes insipidus in 6 patients. In adult population the indication was nocturia in 1941 patients, renal colic in 259 patients, healthy volunteers 13 patients. In 17 studies desmopressin was administered alone while in 3 studies in association respectively with Tolterodina, Ketorolac and Tamsulosin. In 7 studies were reported side effects in only 81 patients, 60 in pediatric population and 21 in adult population. The reported side effects in pediatric population were nausea, lethargy, lower limb weakness, headache, diarrhea, viral gastroenteritis. The reported side effects in adult population were asymptomatic hyponatriemia, nausea, diarrhea, dizziness, symptomatic hyponatriemia. Our review confirm that the MELT formulation of desmopressin guarantee the same response of other formulations with a lower doses and a lowest number of side effects. We believe according with the literature that this formulation is actually the first line and safety treatment for nocturnal enuresis and nocturia.

Determination of the renal concentration capacity following intravenous administration of dDAVP in healthy humans

The synthetic AVP analogue 1-desamino-8-d-arginine-vasopressin (dDAVP) is used for treatment of polyuric disorders. Lack of commercially available assays limits the usefulness of dDAVP as a diagnostic tool in the assessment of renal concentrating capacity. We aimed to develop a specific radioimmunoassay (RIA) for determination of plasma dDAVP (pdDAVP) in order to investigate the relationship between pdDAVP levels and urine osmolality (Uosm). Further, we aimed to determine the onset, duration, and maximum concentrating capacity following intravenous (i.v.) bolus dDAVP injection. The dDAVP assay was based on a well-established RIA for measurements of AVP. Fourteen healthy subjects (aged 15-18 years) participated. Blood and urine samples were collected prior to and after i.v. bolus of 0.03 µg/kg dDAVP. Diuresis and Uosm was measured for nine hours following dDAVP administration. PdDAVP and Uosm were analyzed.We established a specific RIA for the measurement of pdDAVP. All subjects reached maximal pdDAVP concentration (C_max) 30 minutes following infusion, and a rise in Uosm after 60 minutes. Maximal Uosm varied between subjects, with no direct correlation to the achieved pdDAVP levels. We found no significant intra-individual variation between two dDAVP infusions and the effect was reproducible in terms of C_max and maximal Uosm. We characterized the relationship between pdDAVP and Uosm after dDAVP bolus injection in healthy adolescents using our dDAVP assay. Maximal Uosm achieved correlated with the baseline Uosm levels and seemed unrelated to achieved pdDAVP levels. The urine concentrating response was maintained at least eight hours.

Nocturnal Enuresis in India: Are We Diagnosing and Managing Correctly?

Nocturnal enuresis is a common problem affecting school-aged children worldwide. Although it has significant impact on child's psychology, it is always under-recognized in India and considered as a condition which will outgrow with advancing age. Nocturnal enuresis classified as primary or secondary and monosymptomatic or nonmonosymptomatic. Factors that cause enuresis include genetic factors, bladder dysfunction, psychological factors, and inappropriate antidiuretic hormone secretion, leading to nocturnal polyuria. Diagnosis consists of detailed medical history, clinical examination, frequency-volume charts, and appropriate investigations. The frequency-volume chart or voiding diary helps in establishing diagnosis and tailoring therapy. The first step in treating nocturnal enuresis is to counsel the parents and the affected child about the condition and reassure them that it can be cured. One of the effective strategies to manage enuresis is alarm therapy, but currently, it is not easily available in India. Desmopressin has been used in the treatment of nocturnal enuresis for close to 50 years. It provides an effective and safe option for the management of nocturnal enuresis. This review covers the diagnosis and management of nocturnal enuresis and introduces the concept of “bedwetting clinics” in India, which should help clinicians in the thorough investigation of bedwetting cases.

Orally Absorbed Cyclic Peptides

Peptides and proteins are not orally bioavailable in mammals, although a few peptides are intestinally absorbed in small amounts. Polypeptides are generally too large and polar to passively diffuse through lipid membranes, while most known active transport mechanisms facilitate cell uptake of only very small peptides. Systematic evaluations of peptides with molecular weights above 500 Da are needed to identify parameters that influence oral bioavailability. Here we describe 125 cyclic peptides containing four to thirty-seven amino acids that are orally absorbed by mammals. Cyclization minimizes degradation in the gut, blood, and tissues by removing cleavable N- and C-termini and by shielding components from metabolic enzymes. Cyclization also folds peptides into bioactive conformations that determine exposure of polar atoms to solvation by water and lipids and therefore can influence oral bioavailability. Key chemical properties thought to influence oral absorption and bioavailability are analyzed, including molecular weight, octanol-water partitioning, hydrogen bond donors/acceptors, rotatable bonds, and polar surface area. The cyclic peptides violated to different degrees all of the limits traditionally considered to be important for oral bioavailability of drug-like small molecules, although fewer hydrogen bond donors and reduced flexibility generally favored oral absorption.

Oral administration of diluted nasal desmopressin in managing neonatal central diabetes insipidus

BACKGROUND

Neonatal central diabetes insipidus (NCDI) remains a therapeutic challenge, as extremely low doses of enteral desmopressin cannot be titrated with current preparations. The aim of this study was to describe the use of orally administered dilute desmopressin in NCDI.

METHODS

Nasal desmopressin (100 μg/mL) was diluted in 0.9% saline to 10 μg/mL. Infants were treated with 1-5 μg and doses were titrated to a twice-daily regimen. The feed volume was 150 mL/kg/day and titrated according to weight gain.

RESULTS

Five infants aged 6-105 days were included. Stabilizing treatment doses ranged from 2 to 5 μg twice daily in neonates, and 12 μg twice daily in the older infant who was diagnosed at 105 days.

CONCLUSIONS

Dilution of nasal desmopressin with saline facilitates safe administration and dose titration in NCDI. We recommend considering this therapeutic approach to NCDI, particularly in small infants or where alternative treatment regimens have been unsuccessful.

Optimizing response to desmopressin in patients with monosymptomatic nocturnal enuresis

Most patients with monosymptomatic nocturnal enuresis can be effectively treated with an enuresis alarm or antidiuretic therapy (desmopressin), depending on the pathophysiology of the condition in the individual patient. Desmopressin is first-line therapy for enuresis caused by nocturnal polyuria, an excessive urine output during the night. However, in a recent study, around one-third of patients thought to be resistant to desmopressin were subsequently treated effectively with desmopressin monotherapy in a specialist centre. The aim of this article is to review best practice in selecting patients for desmopressin treatment, as well as outline eight recommendations for maximizing the chances of treatment success in patients receiving desmopressin. The roles of formulation, dose, timing of administration, food and fluid intake, inter-individual variation in response, body weight, adherence, withdrawal strategies and combination therapies are discussed in light of the most recent research on desmopressin and enuresis. Possible reasons for suboptimal treatment response are explored and strategies to improve outcomes in patients for whom desmopressin is an appropriate therapy are presented. Through optimization of the treatment plan in primary and specialist care centres, the hope is that fewer patients with this distressing and often embarrassing condition will experience unnecessary delays in receiving appropriate care and achieving improvements.

Oral delivery of macromolecular drugs: Where we are after almost 100years of attempts

Since the first attempt to administer insulin orally in humans more than 90years ago, the oral delivery of macromolecular drugs (>1000g/mol) has been rather disappointing. Although several clinical pilot studies have demonstrated that the oral absorption of macromolecules is possible, the bioavailability remains generally low and variable. This article reviews the formulations and biopharmaceutical aspects of orally administered biomacromolecules on the market and in clinical development for local and systemic delivery. The most successful approaches for systemic delivery often involve a combination of enteric coating, protease inhibitors and permeation enhancers in relatively high amounts. However, some of these excipients have induced local or systemic adverse reactions in preclinical and clinical studies, and long-term studies are often missing. Therefore, strategies aimed at increasing the oral absorption of macromolecular drugs should carefully take into account the benefit-risk ratio. In the absence of specific uptake pathways, small and potent peptides that are resistant to degradation and that present a large therapeutic window certainly represent the best candidates for systemic absorption. While we acknowledge the need for systemically delivering biomacromolecules, it is our opinion that the oral delivery to local gastrointestinal targets is currently more promising because of their accessibility and the lacking requirement for intestinal permeability enhancement.

Primary Nocturnal Enuresis: A Review

Context

Nocturnal enuresis or bedwetting is the most common type of urinary incontinence in children. It has significant psychological effects on both the child and the family. Enuresis nocturna is defined as the inability to hold urine during the night in children who have completed toilet training. It is termed as being “primary” if no continence has ever been achieved or “secondary if it follows at least 6 months of dry nights. The aim of this review was to assemble the pathophysiological background and general information about nocturnal enuresis.

Evidence Acquisition

This review was performed by evaluating the literature on nocturnal enuresis published between 1970 and 2015, available via PubMed and using the keywords “nocturnal enuresis,” “incontinence,” “pediatric,” “review,” and “treatment.”

Results

Children with nocturnal enuresis produce urine at higher rates during the night, and may have lower bladder capacities. Some children with nocturnal enuresis may also have daytime urgency, frequency, and urinary incontinence. Treatment includes aggressive treatment of accompanying constipation or urinary tract infections, behavioral changes, and medical therapy. Alarm therapy remains the first-line treatment modality for primary nocturnal enuresis. High rates of patient compliance and relapse mean that alternative treatments remain on the agenda.

Conclusions

Nocturnal enuresis is a common problem that has multifaceted effects on both the child and the family. Due to multiple etiologic factors, nocturnal enuresis is still not clearly defined.

Advances in the management of primary monosymptomatic nocturnal enuresis in children

Intermittent incontinence of urine in a sleeping child who has previously been dry for less than 6 months without any other lower urinary tract symptoms is considered to be primary monosymptomatic nocturnal enuresis (PMNE). Although, most children outgrow PMNE with age, the psychological impact on the child warrants parental education and patient motivation and treatment. Motivational therapy, alarm therapy and drug therapy are the mainstay of treatment. Motivational and alarm therapy have better success rates than drug therapy alone. Desmopressin is the commonly used first-line drug and is best for short-term relief. Other drugs such as anti-cholinergics, imipramine and sertraline are used in resistant cases. This review focuses on the assessment and treatment of PMNE.

Quality of life in the patients with central diabetes insipidus assessed by Nagasaki Diabetes Insipidus Questionnaire

Central diabetes insipidus (CDI) is characterized by polyuria and polydipsia due to a deficiency of vasopressin. Currently, the treatment goal for CDI is improvement of quality of life (QOL) by desmopressin (DDAVP) without developing hyponatremia. However, there is no reliable measure for QOL in CDI patients. We evaluate our original questionnaire for QOL, consisting of 12 questions focusing on polyuria, polydipsia, and DDAVP treatment, in CDI patients who underwent a switch from nasal spray to oral disintegrating tablets of DDAVP. Twenty-five CDI patients under nasal DDAVP treatment, six with newly developed CDI, and 18 healthy individuals without known polyuric/polydipsic disorders as control subjects were enrolled. QOL scores were determined by our questionnaire at the enrollment and 3 months after the start of oral DDAVP treatment and were examined by the Wilcoxon signed-rank test. Eleven questions detected improvement in QOL. The sum of the QOL scores of the eleven questions increased from 29.2 ± 5.6 under nasal to 36.8 ± 4.5 under oral DDAVP (p < 0.001). There were no clinically relevant changes in serum levels of Na. After eliminating two questions about DDAVP treatment, the sum of QOL scores was 15.3 ± 6.5 in untreated CDI patients, 24.4 ± 5.2 in those with nasal treatment, 28.9 ± 4.9 in those with oral DDAVP, and 29.5 ± 3.6 in healthy controls. The difference among groups was significant (p < 0.05 in Steel-Dwass test) except between patients treated with oral DDAVP and healthy controls. Our questionnaire can be used to accurately assess QOL in CDI patients.

Desmopressin in adult urological disease: clinical evidences

Desmopressin is a synthetic analogue of arginine vasopressin, commercially available since 1974. Desmopressin is proven effective for the treatment primary nocturnal enuresis and polyuria. It has been considered by several investigators for the treatment of nocturia with positive results and is now an established treatment for this indication. In this review, we assessed the available clinical data on desmopressin in adult urological disease.

Management of nocturia: the role of antidiuretic pharmacotherapy

Strategies to manage nocturia include lifestyle modifications and treatment with alpha-blockers, antimuscarinic therapies, and antidiuretics. The concept of achieving success should not be limited to reduction of nighttime voids; it should ideally include proof of improvement of conditions generally associated with nocturia, such as falls, quality of life, and overall health. Few studies have looked specifically at parameters other than nocturnal voids, such as sleep latency, first undisturbed sleep period (FUSP), and total sleep time, including their clinical relevance to patient well-being. Lifestyle modifications, such as voiding before bedtime, limiting caffeine and alcohol, and adjusting medication timing, may be initially effective in mild cases of nocturia. Statistically significant reductions in voiding have been reported with antimuscarinic agents and alpha-blockers as initial therapy, but these reductions generally are not clinically relevant. The antidiuretic therapy desmopressin acetate, a selective vasopressin receptor 2 agonist, is effective in adults with nocturia associated with nocturnal polyuria; however, hyponatremia can occur. The newest formulation-desmopressin orally disintegrating sublingual tablet (ODST)--has greater bioavailability; thus, lower doses can be used, potentially reducing hyponatremia risk. A phase 3 study demonstrated statistically significant reductions in nocturnal voids for desmopressin ODST 50 and 100 µg versus placebo (-1.18 and -1.43 vs. -0.86; P = 0.02 and P < 0.0001, respectively) in patients with nocturia. Treatment was well-tolerated, and low-dose desmopressin ODST was associated with statistically significant increases in duration of FUSP. Development of a validated composite endpoint may help clinicians identify and compare strategies for treating nocturia.

Safety profile of desmopressin tablet for enuresis in a prospective study

INTRODUCTION

This pre-specified sub-study of the desmopressin response in primary nocturnal enuresis study (DRIP study) evaluates the safety profile of the oral desmopressin tablet in children with primary nocturnal enuresis. Endpoints are adverse events and change in body mass index.

METHODS

The DRIP study was an open-label, intention-to-treat, phase IV, multi-national study. Overall, 936 patients were screened and 744 children aged 5-15 years with previously untreated primary nocturnal enuresis were eligible to receive the study medication desmopressin once daily as an oral tablet formulation. At each visit, adverse events were questioned and observed signs or symptoms were recorded.

RESULTS

Overall, 222 (30%) patients experienced 404 treatment-emergent adverse events. The proportion of patients experiencing treatment-emergent adverse events was similar regardless of patient gender or age. Most treatment-emergent adverse events were experienced in three system organ classes: gastrointestinal disorders; infections and infestations; and respiratory, thoracic and mediastinal disorders and were considered unrelated to the study drug. There was a slight increase in body mass index from screening levels during the study, however, clinically not significant.

CONCLUSION

Desmopressin tablet treatment is well tolerated in children with primary nocturnal enuresis, regardless of patient gender or age.

FUNDING

The desmopressin response in primary nocturnal enuresis study (DRIP- study) was funded by Ferring.

Desmopressin orally disintegrating tablet in Japanese patients with central diabetes insipidus: a retrospective study of switching from intranasal desmopressin

Central diabetes insipidus (CDI) is a rare disease characterized by polyuria and polydipsia. Patients with CDI have been successfully treated with desmopressin administered either by intranasal instillation or oral tablets. Recently, a desmopressin orally disintegrating tablet (ODT) was approved as the first oral desmopressin tablet for CDI treatment in Japan. We conducted a retrospective single-center study of 15 Japanese CDI patients treated with desmopressin ODT therapy, which aimed to evaluate the efficacy and safety of switching to desmopressin ODT and to analyze the clinical factors that affect the desmopressin ODT dose in Japanese patients. The daily mean dose of desmopressin ODT was 104 ± 46.30 μg and the mean ratio of oral to nasal desmopressin dose was 17.0 ± 7.6, both of which are considerably smaller than those of previous dose-titration study. Moreover, the nasal spray group needed significantly smaller ratios of nasal to oral desmopressin than the nasal drop group (11.7 ± 6.5 vs 21.0 ± 5.5, p = 0.02). The ratio of oral to nasal desmopressin dose had a significant inverse correlation with the required nasal desmopressin dose. Multiple regression analysis demonstrated the ratios of nasal to oral desmopressin dose depended on intranasal formulations. In conclusion, desmopressin ODT was safe and effective in the treatment of Japanese adult CDI patients. When switching to ODT, we should care about the possibility that patients require smaller ODT doses than what was initially expected based on previously published data and also nasal formulations in terms of their differences of expected switching ratio.

Efficacy of an enuresis alarm, desmopressin, and combination therapy in the treatment of saudi children with primary monosymptomatic nocturnal enuresis

Purpose

We evaluated and compared the effectiveness of an enuresis alarm, desmopressin medication, and their combination in the treatment of Saudi children with primary monosymptomatic nocturnal enuresis (PMNE).

Materials and Methods

A total of 136 children with PMNE were randomly assigned to receive an enuresis alarm alone (EA group, n=45), desmopressin alone (D group, n=46), or a combination of both (EA/D group, n=45). Patients were followed weekly during treatment and for 12 weeks after treatment withdrawal.

Results

During treatment, wetting frequencies were significantly reduced in all groups and remained significantly lower than pretreatment values until the end of follow-up. In the D and EA/D groups, an immediate reduction in wetting frequencies was observed, whereas a longer time was required to reach a significant reduction in the EA group. The full and partial response rates were 13.3% and 37.8% in the EA group, 26.1% and 43.5% in the D group, and 40.0% and 33.3% in the EA/D group. A significant difference was observed only between the EA and EA/D groups (p=0.025). Relapse rates were higher in the D group (66.6%) than in the EA (16.6%) and EA/D (33.3%) groups. A significant difference was observed between the D and EA groups only (p=0.019).

Conclusions

Desmopressin, an enuresis alarm, and combined therapy are effective in the treatment of Saudi children with PMNE. Desmopressin produced an immediate effect but relapses were common. The enuresis alarm provided gradual effects that persisted posttreatment. The combined therapy was superior to the alarm in achieving an immediate response; however, its effect was not better than that of the alarm long term.

Nocturnal enuresis

Nocturnal enuresis (NE) is increasingly seen as part of a heterogeneous phenomenon that at times will include daytime lower urinary tract symptoms such as urgency, frequency and wetting - with reduced bladder storage, usually due to an overactive bladder. In turn, these may be associated with constipation and/or faecal soiling. This paper discusses these considerations in the management of NE.

[Primary monosymptomatic enuresis: diagnostics and therapy]

Nocturnal enuresis is one of the most common problems in childhood. In this article a standardized terminology for basic diagnostics additionally to extended diagnostics will be presented. Depending on the findings a specialized therapy can be performed. Besides drug therapy with antidiuretic hormone (ADH) sleep arousal devices can be used and the combination of both approaches also shows excellent results. At the end of therapy a protracted withdrawal shows better results than abrupt cessation.

The impact of federal warnings on publically funded desmopressin utilization among children in Ontario

OBJECTIVE

To determine whether safety warnings issued by health regulatory agencies regarding desmopressin treatment influenced treatment rates among children.

PATIENT POPULATION AND METHODS

We conducted a time-series analysis using health administrative data from Ontario, Canada, between January 1, 2003 and March 31, 2010. We examined desmopressin prescribing rates among children (<13 years) and investigated the impact of a United States Food and Drug Administration warning (December 2007) and a subsequent Health Canada warning (July 2008) on these rates. A secondary analysis stratified rates according to route of administration.

RESULTS

On average, quarterly desmopressin treatment rates were 29.8% lower following the two warnings (4.7 per 1000 population) compared with the period prior to warnings being issued (6.7 per 1000 population). Structural break analyses identified a significant decrease in overall desmopressin prescribing rates in Q3 2008, with the 95% confidence interval (CI) spanning both safety warnings (Q4 2007 to Q1 2009). A secondary analysis of prescribing rates for oral formulations found consistent results (structural break Q4 2008, 95% CI Q2 2007 to Q2 2009). The average quarterly prescribing rate of intranasal formulations declined by 73.1% following the warnings compared with the period preceding the warnings.

CONCLUSION

Safety warnings issued by regulatory agencies dramatically influenced desmopressin use among Ontario's children.

A retrospective observational study of enuresis, daytime voiding symptoms, and response to medical therapy in children with attention deficit hyperactivity disorder and autism spectrum disorder

INTRODUCTION

Children with attention deficit hyperactivity disorder (ADHD) show an increased prevalence of enuresis and other daytime voiding symptoms (DVS). There is also some evidence toward an increased prevalence of enuresis among children with autism spectrum disorder (ASD), but with no data available with respect to DVS or response to medical treatment. The aim of this study was to assess enuresis and DVS, along with treatment outcomes, in children with ASD, to aid urological management.

METHODS

A retrospective observational study on the incidence of enuresis and other DVS in 671 children with/without ADHD/ASD was performed. Symptomatic improvement ≥50% was required to be considered positive. Complete resolution of symptoms for 3 months after cessation of treatment was considered cure.

RESULTS

Symptomatic improvement with desmopressin or anticholinergic treatment was seen in 76% of patients without ADHD/ASD, 85% of patients with ADHD, and 100% of patients with ASD. Cure was seen in 61% of patients without ADHD/ASD, 48% of patients with ADHD, and 50% patients with ASD. Mean time to cure was 9 months in those without ADHD/ASD (N = 319), 10 months in those with ADHD (N = 62), and 8 months in those with ASD (N = 10) (P = 0.69).

CONCLUSION

Despite the small sample size of patients with ASD, our data show a favorable trend toward efficacy of desmopressin and anticholinergic therapy in these children with enuresis and DVS.

Desmopressin treatment regimens in monosymptomatic and nonmonosymptomatic enuresis: A review from a clinical perspective

OBJECTIVE

To evaluate outcomes of desmopressin treatment in monosymptomatic enuresis (ME) and nonmonosymptomatic enuresis (NME).

MATERIALS AND METHODS

PubMed was searched for all studies investigating enuresis, up to July 2009, in which desmopressin was administered alone or combined with other treatments. Each study was graded according to its respective level of evidence.

RESULTS

Altogether, 99 studies enrolling 7422 patients were identified as fulfilling the inclusion criteria. In 76 studies, desmopressin was administered as monotherapy; in 29 it was combined with other treatments such as antimuscarinics and enuresis alarm.

CONCLUSION

Studies incorporating a minor invasive versus a non-invasive diagnostic approach seem to achieve superior long-term success rates. Primary efficacy outcomes following desmopressin treatment are more favourable in ME than NME. Desmopressin administered with adjunct measures achieves superior outcomes compared to monotherapy, especially in NME. Compared to sudden withdrawal, the structured withdrawal programs show better long-term success and lower relapse rates. So far, no superiority has been shown for either time- or dose-dependent structured withdrawal programs. Most studies incorporated only small case series; only 25 studies with level of evidence 1 or 2 have been conducted. The broad range of mono- and adjunct treatments were evaluated according to the evidence based criteria recommended by the European Association of Urology.

Did the removal of the indication of nocturnal enuresis for intranasal desmopressin change prescribing practice?

PURPOSE

The indication for the treatment of primary nocturnal enuresis was removed from all intranasal preparations of desmopressin in May 2007. Objective of this study was to examine whether and how fast this regulatory decision changed prescribing in affected children.

METHODS

We analyzed claims data of the Gmünder ErsatzKasse (GEK) over the years 2004-2008. All children and adolescents aged 0-18 years who received at least one out-patient diagnosis of urinary incontinence in the corresponding years were included. Our outcome of interest was the proportion of oral desmopressin and its change over time.

RESULTS

A total of 6308 to 7207 children with a mean age of about 8 years were included annually (62-63% were male) and 14 746 packages of desmopressin were analysed (49.9% intranasal; 50.1% oral; 0.01% parenteral preparations). The proportion of patients using desmopressin decreased slightly from 13.9% in 2004 to 12.6% in 2008 ( p for trend = 0.0131). Between January 2004 (39.1%) and December 2006 (41.3%), the proportion of oral forms was nearly constant and doubled after that within a few months to about 80%.

CONCLUSIONS

Immediately after the removal of the indication for intranasal desmopressin, an increased prescribing of tablet forms in affected children was found in Germany.

Is there still a role for desmopressin in children with primary monosymptomatic nocturnal enuresis?: a focus on safety issues

It has recently became apparent that severe primary monosymptomatic nocturnal enuresis (MNE) has a worse prognosis than generally believed, and may have major consequences on the well-being of the child, thus making treatment mandatory. Desmopressin is one of the most widely prescribed medications for MNE, and in this current opinion article we discuss the safety of desmopressin in children with this condition. Following a US FDA request in December 2007 that the prescribing information for desmopressin nasal spray be updated, desmopressin spray is no longer indicated for the treatment of MNE or for use in patients at risk for hyponatraemia. Multiple reports of hyponatraemia in patients with nocturia (mainly the elderly) led to an increased awareness of the risks associated with desmopressin. While the pathogenesis of hyponatraemia in those over 65 years of age relates more to changing renal water and solute handling, we believe that in the young, overdosing and insufficient fluid restriction are usually the major causes. Hyponatraemia is most frequently reported when desmopressin is administered by nasal spray compared with the tablet formulation. This may simply reflect the fact that for more than 10 years the spray was the only available mode of administration in many countries. However, it may also reflect the higher biodisponibility and/or intraindividual variability of pharmacokinetics of the spray compared with the tablet. There are few serious adverse events reported for the melt formulation (oral lyophilisate), but as it has only recently become available on the market, it would be premature to conclude that it has a better safety profile. We believe that desmopressin in all formulations has a good safety profile in children with MNE, provided that treatment is properly prescribed and monitored; improving the training of doctors and patients in the dose-response kinetics of the drug, teaching appropriate restriction of fluid intake and by encouraging the use of desmopressin within a narrow dose range (10-20 microg spray, 120-240 microg melt and 200-400 microg tablet) when used in primary-care settings. Titrating higher doses in therapy-resistant patients should probably be carried out in a specialized enuresis centre, and only after documenting adequate morning urinary diluting capacity. In summary, the risk of hyponatraemia is exacerbated by misuse of the drug rather than an inherent danger associated with the drug, which in our opinion should be addressed with better education rather than withdrawal of a medication that has the potential to benefit children with nocturnal enuresis.

Desmopressin for the treatment of primary nocturnal enuresis

Primary nocturnal enuresis (PNE) affects a large proportion of children aged 5 years and over, and can persist into adolescence if left untreated. To patients and families, the condition is extremely distressing and embarrassing, as well as inconvenient owing to the increased washing of bedclothes required, and the difficulties surrounding socializing, such as planning sleepovers or holidays. PNE is caused by a mismatch between the capacity of the bladder to store urine and the volume of urine produced at night, which is frequently excessive in children with PNE. Excessive urine production at night can be caused by an impairment of the circadian rhythm of antidiuretic hormone secretion. Treatment for PNE is primarily by means of behavioral conditioning or pharmacological therapy. Desmopressin is a synthetic analogue of naturally occurring antidiuretic hormone, and is the only pharmacological therapy with a Grade A, level 1 recommendation from the International Consultation on Incontinence as a first-line treatment for PNE. Desmopressin is a well-established and generally well-tolerated treatment for nocturnal enuresis. The only potentially serious adverse effect of desmopressin is hyponatremia, which is rare and has predominantly been observed with the intranasal form of the drug – this formulation has now been withdrawn for the PNE indication in most countries. This review will explore the pharmacology, clinical efficacy and tolerability of desmopressin and its oral formulations in PNE, including the tablet and the more recent oral lyophilisate.

Diagnosis and management of nocturnal enuresis

PURPOSE OF REVIEW

To highlight recent advances in enuresis research.

RECENT FINDINGS

Many discoveries have distanced us from the time when bedwetting was considered a psychiatric disorder. Instead, it is now agreed that nocturnal polyuria, detrusor overactivity, and high arousal thresholds are, in various combinations, central to enuresis pathogenesis. All three mechanisms have been further elucidated during the last year. It has been found that solute diuresis, and not just free-water diuresis due to vasopressin deficiency, may be causative. Sonographical bladder wall measurements have been shown to have prognostic value in detrusor-dependent enuresis, and fascinating proof for the interplay between the bladder and the sleeping brain has been put forward. And, ironically, sleep research has caused psychiatry to make a slight comeback, as studies have indicated that enuretic children may suffer from cognitive problems due to suboptimal sleep. Less has been achieved regarding treatment, but some evidence has finally supported the experience that anticholinergics may be effective in therapy-resistant enuresis.

SUMMARY

During the last years, increased insight has been gained into the multifaceted pathogenesis of enuresis, but there is still an irritating lack of proven effective therapies.

Evidence of partial anti-enuretic response related to poor pharmacodynamic effects of desmopressin nasal spray

PURPOSE

Desmopressin is an evidence-based medicine level I, category A therapy for monosymptomatic nocturnal enuresis. However, in up to 40% of patients only partial desmopressin response is obtained. While the poor pharmacokinetic characteristics of the different available formulations may have a role in apparent therapy resistance, there are limited data available to support this theory. We sought to identify pharmacodynamic factors involved in partial desmopressin response or desmopressin resistance in children with monosymptomatic nocturnal enuresis, with special emphasis on concentrating performance, and time to reach and duration of maximal urine concentration.

MATERIALS AND METHODS

We evaluated 64 children with monosymptomatic nocturnal enuresis and proved nocturnal polyuria lacking full response to desmopressin treatment. The study involved 2 separate home based test days (A and B), each consisting of 9 timed urine collections starting in the evening 1 hour before desmopressin administration and continuing for 16 hours following desmopressin administration. Test A was done during fluid restriction, and test B was done during an oral fluid load.

RESULTS

Under fluid restriction 16 patients failed to achieve urine concentration greater than 850 mOsmol/l at the midnight collection following desmopressin administration. After an oral fluid load given at the start of the test the majority of patients failed to reach maximal concentration of urine as voided during hydropenia, and 45 patients failed to regain appropriate dilution of urine even when an oral water load of 15 ml/kg (urine osmolality less than 750 mOsmol/l) was given in the morning at the end of the test. This finding is suggestive of a prolonged duration of action of the drug.

CONCLUSIONS

Pharmacodynamic tests reveal a suboptimal effect of desmopressin on urine concentration in a significant percentage of patients, which worsens when fluid is not restricted before desmopressin administration. Also the time to reach maximal antidiuretic effect and the duration of pharmacodynamic action show a wide range, requiring individualization of mode and time of administration. Our data demonstrate that a simple pharmacodynamic test as described may give important information on time of dosing, duration of action and influence of oral fluid intake, allowing individualization of therapy. Data also reveal that desmopressin should be administered at least 1 hour before bedtime, and that in case of therapy resistance a longer interval, up to 2 hours, might further reduce diuresis rate in the early night. Because of the documented prolonged action of desmopressin in some patients, increasing the dose without performing pharmacodynamic testing is no longer acceptable.