First uninterrupted sleep period in children and adolescents with nocturnal enuresis: Added value in diagnosis and follow-up during therapy.

BACKGROUND: The first uninterrupted sleep period (FUSP, time up to the first episode of enuresis/nocturia after falling asleep) is a frequently investigated parameter in adults with nocturia, as it correlates with quality of life. However, it has not been included in pediatric enuresis studies. AIM: Investigate FUSP, circadian renal water and sodium handling, as well as sleep quality before and after desmopressin therapy in enuresis. MATERIALS AND METHODS: We conducted a post hoc analysis of a prospective study in 30 treatment-naïve children with enuresis who underwent a video-polysomnography and a 24-h urine concentration profile before and after 6 months of desmopressin therapy. We analyzed FUSP, periodic limb movements in sleep (PLMS), and arousal indexes and their correlations with the urinary parameters. RESULTS: Sixteen children with a mean age of 10.9 ± 3.1 years had full registrations and were included in this subanalysis. After therapy, FUSP was significantly longer (p < 0.001), and the PLMS index was lower (p = 0.023). Significant differences in the circadian rhythm of diuresis (night/day diuresis, p = 0.041), nocturnal urinary osmolality (p = 0.009), and creatinine (p = 0.001) were found, demonstrating the increase of urinary concentration overnight by desmopressin, as well as a significant antidiuretic effect (diuresis [p = 0.013] and diuresis rate (p = 0.008). There was no correlation between the difference of FUSP, PLMS index, and urinary parameters. Nevertheless, despite this study being underpowered, there are indications of a correlation between nocturnal diuresis and diuresis rate. RESULTS: Our results support the need for further research regarding FUSP in children with enuresis, in accordance with nocturia studies in adults, as this parameter could be valuable in the follow-up and evaluation of therapeutic strategies for enuresis.

Claiming desmopressin therapeutic equivalence in children requires pediatric data: a population PKPD analysis.

PURPOSE: For a new formulation of a drug, only pharmacokinetic bioequivalence with the original formulation has to be demonstrated in healthy, young adults. However, "children are not small adults," and to guarantee a safe and effective treatment, age-adapted drug development is required. Desmopressin, a vasopressin analogue prescribed for nocturnal enuresis in children, was studied as an example formulation first developed in adults and then extrapolated to a pediatric indication. METHODS: Population pharmacokinetic and pharmacodynamic modeling was used to analyze previously published desmopressin data of 18 children suffering from nocturnal enuresis. The main objective was the comparison of the therapeutic equivalence of two desmopressin formulations: tablet and lyophilisate. The measurements for pharmacokinetics and pharmacodynamics were respectively plasma desmopressin concentration and urine osmolality and diuresis. RESULTS: The half maximal inhibitory concentration for inhibition of urine production was 0.7 pg/mL lower for the lyophilisate than for the tablet. The effect of formulation on the half maximal inhibitory concentration seems to suggest that the 120-µg lyophilisate has a more pronounced effect on the urine volume and osmolality than the 200-µg tablet, even when the same exposure is achieved. CONCLUSIONS: A new indirect response model for desmopressin was constructed and validated, using a previously built pharmacokinetic model and additional pharmacodynamic data. In order to draw solid conclusions regarding the efficacy and safety of desmopressin in children, pharmacokinetics and pharmacodynamics data should be analyzed together. This study adds proof to potential differences in pediatric and adult pharmacokinetic and pharmacodynamic properties of desmopressin and exemplifies the need for pediatric clinical trials, not only for every new drug but also for every new formulation.

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.

Incontinence and psychological problems in children: a common central nervous pathway?

Nocturnal enuresis is caused by a mismatch between the nocturnal bladder capacity and the nocturnal diuresis rate, in the presence of a deficient arousability in the majority of patients, according to the pediatric and urologic literature. Psychiatric and psychologic literature are still concentrating on the potential role of psychological factors and central nervous mechanisms in the pathogenesis, as is reflected in the DMS-5 criteria. However, research has clearly shown several important comorbidities between neuropsychological dysfunctions and nocturnal enuresis. Due to the increased comorbidity of (neuro)psychological problems, sleep problems, circadian rhythms, and enuresis, the question arises as to whether there is a possible common central pathway in the pathogenesis. It is likely that the coexistence of these problems can be attributed to a common central nervous system involvement. The specific role of the central nervous system remains unclear, but several pathways are possible. The high comorbidity between enuresis, sleep, and (neuro)psychological functioning is probably attributable to a common pathogenetic pathway, emphasizing the importance of a multidisciplinary focus in screening and treatment in children with nocturnal enuresis.

Desmopressin (melt) therapy in children with monosymptomatic nocturnal enuresis and nocturnal polyuria results in improved neuropsychological functioning and sleep.

BACKGROUND: There is a high comorbidity between nocturnal enuresis, sleep disorders and psychological problems. The aim of this study was to investigate whether a decrease in nocturnal diuresis volume not only improves enuresis but also ameliorates disrupted sleep and (neuro)psychological dysfunction, the major comorbidities of this disorder. METHODS: In this open-label, prospective phase IV study, 30 children with monosymptomatic nocturnal enuresis (MNE) underwent standardized video-polysomnographic testing and multi-informant (neuro)psychological testing at baseline and 6 months after the start of desmopressin treatment in the University Hospital Ghent, Belgium. Primary endpoints were the effect on sleep and (neuro)psychological functioning. The secondary endpoint was the change in the first undisturbed sleep period or the time to the first void. RESULTS: Thirty children aged between 6 and 16 (mean 10.43, standard deviation 3.08) years completed the study. The results demonstrated a significant decrease in periodic limb movements during sleep (PLMS) and a prolonged first undisturbed sleep period. Additionally, (neuro)psychological functioning was improved on several domains. CONCLUSIONS: The study demonstrates that the degree of comorbidity symptoms is at least aggravated by enuresis (and/or high nocturnal diuresis rate) since sleep and (neuro)psychological functioning were significantly ameliorated by treatment of enuresis. These results indicate that enuresis is not such a benign condition as has previously been assumed.

Sleep fragmentation and periodic limb movements in children with monosymptomatic nocturnal enuresis and polyuria.

BACKGROUND: Children with nocturnal enuresis (NE) have been found to have sleep fragmentation and a high incidence of periodic limb movements in sleep (PLMS). This study explored the association of monosymptomatic NE and polyuria in relation to fluid intake, bladder volume, number of wet nights, and number of nights with polyuria to the frequency of PLMS and cortical arousals during sleep. MATERIALS AND METHODS: Thirty children with monosymptomatic NE and polyuria were enrolled in the study. Enuretic parameters were determined by diaries, forced drinking, uroflow, and ultrasound examination. All subjects participated in one polysomnographic study. The number of cortical arousals and PLMS were compared with those recorded in a former pilot study which included only children with refractory NE. RESULTS: Of the 30 children who participated in the study, the mean age was 10.43 ± 3.08 (range 6-16) years, and 23 were boys. The PLMS index was positively associated with the arousal index and the awakening index (p < 0.001). No significant association between the sleep and the enuretic parameters was found. Children with refractory NE showed a significantly higher PLMS index (p < 0.001). CONCLUSIONS: We found that PLMS and cortical arousals in sleep were increased in children with monosymptomatic NE and polyuria, without a significant association with the enuretic parameters. These observations suggest the presence of a comorbid mechanism driven by a common, independent pacemaker. We hypothesize the autonomic system, its sympathetic branch, and the dopaminergic system as candidates for this pacemaker.

Periodic limb movements during sleep are associated with a lower quality of life in children with monosymptomatic nocturnal enuresis.

UNLABELLED: The study investigates whether cortical arousals and periodic limb movements during sleep are related to daytime psychological functioning in children with monosymptomatic nocturnal enuresis with associated nocturnal polyuria. Psychological functioning is evaluated on five domains: attention deficit hyperactivity disorder-inattentive problems, quality of life, internalizing problems, externalizing problems, and executive functioning. This multi-informant (parents, teachers, and children) and multi-method study included overnight video-polysomnography, questionnaires, and neuropsychological testing. Thirty children (7 girls) 6 to 16 years (mean 10.43 years, SD 3.08) were selected in a tertiary enuresis center. A high index of periodic limb movements during sleep was associated with a lower quality of life, according to the child. No significant correlations were found with attention deficit hyperactivity disorder-inattentive problems, internalizing problems, externalizing problems, and executive functioning. CONCLUSION: This study clarifies the relationship between sleep parameters and psychological functioning of the children with monosymptomatic nocturnal enuresis and associated nocturnal polyuria according to the child, the parents, and the teachers. Periodic limb movements during sleep are associated with a lower quality of life of the child.

Pharmacokinetics of desmopressin administered as tablet and oral lyophilisate formulation in children with monosymptomatic nocturnal enuresis.

Desmopressin 120 µg oral lyophilisate and 200 µg tablet are considered bioequivalent, based on extrapolation of studies in a limited number of adults and on one dose-finding study of desmopressin oral lyophilisate in children. However, no comparative pharmacokinetic study in children was executed confirming this statement. No data are available on the influence of food intake on the bioavailability of desmopressin tablet in a pediatric setting, although studies in adults have documented that food intake results in a significantly lower desmopressin plasma concentration. In this study, we analyzed plasma concentrations of desmopressin oral lyophilisate and tablet with concomitant food intake. Twenty-three children with monosymptomatic nocturnal enuresis (mean age, 12.7 years) were recruited. Two tests were performed on two separate days in identical conditions with a standardized food and fluid intake. Desmopressin was administered as desmopressin tablet or desmopressin oral lyophilisate immediately after a meal. Desmopressin plasma concentration was measured at 1 h, 2 h, and 6 h postdosing. No significant difference in plasma concentration of 120 µg desmopressin oral lyophilisate and 200 µg tablet was demonstrated, even with concomitant food intake. A significant difference in variability was found, identifying a smaller variance for desmopressin oral lyophilisate plasma concentrations at all time points. This study demonstrates comparable plasma levels for desmopressin oral lyophilisate, despite the lower dose. The dosage for desmopressin oral lyophilisate is more predictable due to the significantly smaller variance. Therefore, desmopressin oral lyophilisate seems more suitable, especially in the younger age group for which time interval between dinner and drug administration is limited.

Desmopressin melt improves response and compliance compared with tablet in treatment of primary monosymptomatic nocturnal enuresis.

UNLABELLED: Primary nocturnal enuresis is a prevalent childhood condition that can persist into adulthood. Desmopressin is an antidiuretic available as orally disintegrating lyophilisate (melt) or solid tablet. Recent findings suggesting different food interactions and clinical characteristics, including compliance, between desmopressin melt and tablet motivated a post hoc analysis of a previously reported randomised, crossover study. The efficacy of desmopressin melt compared with tablet was evaluated using the International Children's Continence Society (ICCS) responder definitions. Compliance was further analysed using detailed criteria, and the association between efficacy and compliance was examined. In total, 221 patients aged 5-15 years, already receiving desmopressin tablets were randomised to the treatment sequence melt (120/240 µg)/tablet (0.2/0.4 mg) or tablet/melt in two consecutive 3-week periods. The probability of being a responder (partial or full) during either period was significantly more likely with desmopressin melt compared with tablet (odds ratio, 2.0; confidence intervals, 1.07-3.73; p = 0.03). There was no period effect on compliance in the tablet/melt sequence and no difference in the number of completely compliant patients in each formulation group; however, more patients were >75 % compliant in period 1 compared with period 2 in the melt/tablet sequence. Increased compliance was associated with greater reductions in the number of wet nights for both formulations. CONCLUSIONS: Desmopressin melt, compared with tablet, improves the probability of being a responder. Switching from tablet to melt formulation increased patient compliance. Increased compliance was associated with increased efficacy. Switching to desmopressin melt may benefit patients with suboptimal responses to desmopressin tablet.

Desmopressin oral lyophilisate in young children: new insights in pharmacokinetics and pharmacodynamics.

OBJECTIVE: To study the pharmacokinetic (PK)/pharmacodynamic (PD) characteristics of desmopressin (dDAVP) oral lyophilisate in children below the age of 8 years with special emphasis on age-related and size-related differences in bioavailability. DESIGN: Open label, non-randomised, interventional PK and PD trial. SETTING: Single-centre study. PATIENTS: Children (age: 6 months to 8 years) with nocturnal polyuria, including both children with uropathy or nephropathy (glomerular filtration rate >60 mL/min/1.73 m²) and children (age: 5-8 years) with severe monosymptomatic nocturnal enuresis, who were unresponsive to treatment with 400 µg of the dDAVP tablet for at least 1 month. INTERVENTIONS: After a water load, dDAVP was administered sublingually as a single dose of oral lyophilisate. Subsequently, blood and urine samples were collected until 7 hours post-administration. MAIN OUTCOME MEASURES: Non-compartmental analysis of PK parameters was performed based on dDAVP concentrations in both plasma and urine. To evaluate the effect of dDAVP lyophilisate (PD parameters), the urinary concentration capacity (urine osmolality (mOsm/kg)) and antidiuretic effect (diuresis rate (mL/kg/h)) were calculated. RESULTS: The PK data support the need for size-dependent dosing in children. Body weight was shown to be a significant covariate for apparent clearance (CL/F) and apparent volume of distribution (Vd/F). A double absorption peak of dDAVP lyophilisate in the first 2 hours post-administration was demonstrated. CONCLUSIONS: For the first time, a double absorption profile of dDAVP lyophilisate was found in children, questioning extrapolation of bioequivalence from adults towards children. Moreover, the need for size-adapted dosing regimens of dDAVP lyophilisate in young children is indicated. TRIAL REGISTRATION NUMBER: NTC02584231.

An Integrated Paediatric Population PK/PD Analysis of dDAVP: How do PK Differences Translate to Clinical Outcomes?

INTRODUCTION: The bioequivalence of two formulations of desmopressin (dDAVP), a vasopressin analogue prescribed for nocturnal enuresis treatment in children, has been previously confirmed in adults but not in children. In this study, we aimed to study the pharmacokinetics (PK) and pharmacodynamics (PD) of these two formulations, in both fasted and fed children, including patients younger than 6 years of age. METHODS: Previously published data from one PK study and one PK/PD study in children aged between 6 and 16 years were combined with a new PK/PD study in children aged between 6 months and 8 years, and analysed using population PK/PD modelling. Simulations were performed to further explore the relative bioavailability of both formulations and evaluate current dosing strategies. RESULTS: The complex absorption behaviour of the lyophilizate was modelled using a double input, linked to a one-compartmental model with linear elimination and an indirect response model linking dDAVP concentration to produced urine volume and osmolality. The final model described the observed data well and elucidated the complexity of bioequivalence and therapeutic equivalence of the two formulations. Simulations showed that current dosing regimens using a fixed dose of lyophilizate 120 µg is not adequate for children, assuming children to be in the fed state when taking dDAVP. A new age- and weight-based dosing regimen was suggested and was shown to lead to improved, better tailored effects. CONCLUSIONS: Bioequivalence and therapeutic equivalence data of two formulations of the same drug in adults cannot be readily extrapolated to children. This study shows the importance of well-designed paediatric clinical trials and how they can be analysed using mixed-effects modelling to make clinically relevant inferences. A follow-up clinical trial testing the proposed dDAVP dosing regimen should be performed. CLINICAL TRIAL REGISTRATION: This trial has been registered at www.clinicaltrials.gov (identifier NCT02584231; EudraCT 2014-005200-13).

Abnormal sleep architecture and refractory nocturnal enuresis.

PURPOSE: The relation between sleep and nocturnal enuresis has been an area of discussion for many years. Children with enuresis are generally believed to have sleep that is too deep with decreased arousability. We investigated sleep characteristics in children with refractory nocturnal enuresis. MATERIALS AND METHODS: Nine girls and 20 boys between 5 and 19 years old (mean +/- SD age 12.1 +/- 2.7) diagnosed with desmopressin dependent (14) and/or resistant (15) nocturnal enuresis and nocturnal polyuria underwent a standardized investigation protocol, including 1 night of polysomnography. Two age groups of 4 boys and 2 girls 5 to 9 years old, and 16 boys and 7 girls 10 to 19 years old were compared to previously defined controls, including 5 boys and 2 girls 5 to 9 years old and 7 boys and 2 girls 10 to 19 years old. Five to 9 and 10 to 19-year-old controls had a mean of 4.2 +/- 1.5 and 3.3 +/- 0.6 periodic limb movements per hour of sleep, respectively. The total number of arousal-awakenings during sleep was 21.6 +/- 8.1 at ages 5 to 9 years and 21.7 +/- 12.8 at ages 10 to 19. RESULTS: All except 1 patient had greater than 5 periodic limb movements per sleep hour. The younger and older age groups had a mean of 18.6 +/- 5.7 and 18 +/- 7.8 periodic limb movements per sleep hour, respectively. Total arousal-awakenings were also increased at 86.7 +/- 58.1 and 73.8 +/- 34.8, respectively. Statistical differences were calculated with the Mann-Whitney U test in controls vs the study population for periodic limb movements and in the 2 age groups for arousal-awakening (p = 0.003 and <0.001, respectively). CONCLUSIONS: Preliminary data indicate a high incidence of periodic limb movements in sleep at night in children with refractory nocturnal enuresis and increased cortical arousability, leading to awakening.

Poor compliance with primary nocturnal enuresis therapy may contribute to insufficient desmopressin response.

PURPOSE: Studies of desmopressin in children with primary nocturnal enuresis show a greater than 90% decrease in wet nights in 20% to 30%, a 50% to less than 90% decrease in 20% to 40% and less than a 50% decrease in up to 60%. Insufficient response to desmopressin is attributable to various factors, including differences in the primary nocturnal enuresis definition, underlying bladder dysfunction and/or desmopressin pharmacokinetic characteristics. However, little attention has been given to poor compliance with therapy as a possible explanatory factor. For a drug with an effect duration limited to the night after administration a high degree of compliance is essential to ensure consistent therapeutic effects. MATERIALS AND METHODS: This was a substudy of an international investigation of treatment for 6 months or less with desmopressin tablets in children with primary nocturnal enuresis. Medication was dispensed at each visit as required and collected at each subsequent visit. Compliance was determined by pill counts by study staff. RESULTS: Compliance data were available on 723 patients. Of the patients 81% to 91% ingested all medication as instructed during the initial run-in phases. However, this decreased to 77% and 71% during the first and second 3-month treatment periods, respectively. CONCLUSIONS: Patient motivation and compliance are generally stronger in clinical trials than in clinical practice. However, this study shows that some patients were poorly compliant with medication even at study initiation and only 71% were fully compliant with long-term treatment. Decreased compliance was associated with a lower response rate. Patients should be encouraged to comply fully with treatment to achieve an optimal outcome.

Recent advances in managing and understanding enuresis.

Enuresis, particularly in children during sleep, can be a debilitating condition, affecting the quality of life of the child and his or her family. The pathophysiology of nocturnal enuresis, though not clear, revolves around the inter-related mechanisms of overactive bladder, excessive nocturnal urine production, and sleep fragmentation. The first mechanism is more related to isolated nocturnal voiding, whereas the latter two are more related to nocturnal enuresis, in which circadian variations in arginine vasopressin hormone play a key role. A successful treatment would depend upon appropriately addressing the key factors precipitating nocturnal enuresis, necessitating an accurate diagnosis. Thus, advancements in diagnostic tools and treatment options play a key role in achieving overall success. This review summarizes recent advances in understanding the pathophysiology of nocturnal enuresis, diagnostic tools, and treatment options which can be explored in the future.

Challenging factors for enuresis treatment: Psychological problems and non-adherence.

The evidence for organic pathogenetic factors in enuresis and the discovery of effective therapies targeting the bladder and/or nocturnal diuresis have overwhelmed every potential role of psychological factors in pathogenesis and treatment. However, psychopathology is still important in enuresis because according to the document of the International Children's Continence Society (ICCS) 20-30% of the children with enuresis have at least one psychological/psychiatric disorder at rates two times higher than non-wetting children. The most common comorbid disorder with enuresis is attention deficit hyperactivity disorder. The aim of this review is to translate the existing evidence on the importance of a psychological screening into daily clinical practice of the medical practitioner. The use of the minimal psychological screening tool should be considered mandatory in each primary setting. If psychological problems are indicated, referral of the patient to a multidisciplinary setting should be considered, not only to allow psychological assessment to screen for a possible psychopathology, but also since therapy resistance might be expected. This review concentrates on two items from psychopathology/psychotherapy that might predict insufficient treatment response: the psychological comorbidities as described according to the DSM-5 criteria and the underestimated importance of therapy adherence. Adherence is a cornerstone of effective therapy in enuresis. It is a problem involving the doctor, the patient, and the parents. Increasing adherence takes effort and is time-consuming. But it is worthwhile knowing that several studies have demonstrated that high adherence is associated with high therapy success of enuresis. Eventually, this is the ultimate goal of treatment.

Predictive parameters of response to desmopressin in primary nocturnal enuresis.

INTRODUCTION/BACKGROUND: Many recent treatment guidelines have advocated the importance of a full noninvasive medical evaluation. To individualize treatment, special emphasis must be put on recording of the maximum voided volume (MVV) and nocturnal diuresis in a diary or frequency/volume chart. OBJECTIVE: The aim of this study was to identify any possible predictive factors to desmopressin response. STUDY DESIGN: This study is a re-analysis of a prospective, open-label, multinational, phase-IV study evaluating ≤6 months of treatment with desmopressin tablets for children with primary nocturnal enuresis. The children were enrolled between April 2002 and December 2004 from 86 centers in four countries: UK, Canada, Germany and France. A total of 936 children were screened; 744 children aged 5-15 years participated in the study. Of these, 471 children completed the study with 6 months follow-up and recording in a frequency/volume chart. All children experienced six or more wet nights during the 14-day screening period. Exclusion criteria were: organic pathology, treatment for enuresis within the past year, previous treatment for enuresis for >4 weeks, diurnal symptoms, renal or central diabetes insipidus and the use of systemic antibiotics or other drugs known to affect desmopressin activity. The predictive value of number of wet nights a week, fluid intake, daytime voiding frequency and diuresis was investigated by performing a multinomial logistic regression. RESULTS: Of the demographic variables, age was the only significant predictor for response to desmopressin. Controlling for age, the significant predictive variables were: number of wet nights a week, average voided volume daytime, maximum voided volume daytime, total daytime diuresis, nocturnal diuresis (see Figure), maximum voided volume 24 h and total 24 h diuresis. More than 80% of the children had no nocturnal polyuria and a low maximum voided volume. DISCUSSION: Performing a secondary analysis is a limitation because the original study was not designed for that. A new prospective study is ethically hardly defendable for children if data are available from previous literature [1]; therefore, a re-analysis was the appropriate choice. The study confirms the predictive value of age, number of wet nights a week and nocturnal diuresis [1,2]. CONCLUSIONS: The study demonstrates that desmopressin response rates are higher in children with greater age, limited number of wet nights a week and nocturnal polyuria. Only a minority of a primary nocturnal enuresis population, based on history alone, had nocturnal polyuria. The majority had a low maximum voided volume. The results clearly stress the importance of a frequency/volume chart for individualizing therapy to the characteristics, thereby resulting in elevated success rates. Registration number of clinical trial: Clinical Trials.gov NCT00245479.

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.

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.