Induction of narcolepsy-like symptoms by orexin receptor antagonists in mice

Orexins/hypocretins are hypothalamic neuropeptides that promote and stabilize wakefulness by binding to the orexin receptor type-1 (OX1R) and type-2 (OX2R). Disruption of orexinergic signaling results in the sleep disorder narcolepsy in mice, rats, dogs, and humans. The orexin receptor antagonist suvorexant promotes sleep by blocking both OX1R and OX2R. Whereas suvorexant has been clinically approved for the treatment of insomnia because it is well tolerated in experimental animals as well as in human patients, a logical question remains as to why orexin receptor antagonists do not induce overt narcolepsy-like symptoms. Here we show that acute and chronic suvorexant promotes both rapid eye movement (REM) and non-REM (NREM) sleep without inducing cataplexy in mice. Interestingly, chronic suvorexant increases OX2R mRNA and decreases orexin mRNA and peptide levels, which remain low long after termination of suvorexant administration. When mice are chronically treated with suvorexant and then re-challenged with the antagonist after a 1-week washout, however, cataplexy and sleep-onset REM (SOREM) are observed, which are exacerbated by chocolate administration. Heterozygous orexin knockout mice, with lower brain orexin levels, show cataplexy and SOREM after acute suvorexant administration. Furthermore, we find that acute suvorexant can induce cataplexy and SOREM in wild-type mice when co-administered with chocolate under stress-free (temporally anesthetized) conditions. Taken together, these results suggest that suvorexant can inhibit orexin synthesis resulting in susceptibility to narcolepsy-like symptoms in mice under certain conditions.

γ-Hydroxybutyric Acid: Pharmacokinetics, Pharmacodynamics, and Toxicology

Gamma-hydroxybutyrate (GHB) is a short-chain fatty acid present endogenously in the brain and used therapeutically for the treatment of narcolepsy, as sodium oxybate, and for alcohol abuse/withdrawal. GHB is better known however as a drug of abuse and is commonly referred to as the "date-rape drug"; current use in popular culture includes recreational "chemsex," due to its properties of euphoria, loss of inhibition, amnesia, and drowsiness. Due to the steep concentration-effect curve for GHB, overdoses occur commonly and symptoms include sedation, respiratory depression, coma, and death. GHB binds to both GHB and GABAB receptors in the brain, with pharmacological/toxicological effects mainly due to GABAB agonist effects. The pharmacokinetics of GHB are complex and include nonlinear absorption, metabolism, tissue uptake, and renal elimination processes. GHB is a substrate for monocarboxylate transporters, including both sodium-dependent transporters (SMCT1, 2; SLC5A8; SLC5A12) and proton-dependent transporters (MCT1-4; SLC16A1, 7, 8, and 3), which represent significant determinants of absorption, renal reabsorption, and brain and tissue uptake. This review will provide current information of the pharmacology, therapeutic effects, and pharmacokinetics/pharmacodynamics of GHB, as well as therapeutic strategies for the treatment of overdoses. Graphical abstract.

A practical guide to the pharmacological and behavioral therapy of Narcolepsy

Narcolepsy is a rare, chronic, and disabling central nervous system hypersomnia; two forms can be recognized: narcolepsy type 1 (NT1) and narcolepsy type 2 (NT2). Its etiology is still largely unknown, but studies have reported a strong association between NT1 and HLA, as well as a pathogenic association with the deficiency of cerebrospinal hypocretin-1. Thus, the most reliable pathogenic hypothesis is an autoimmune process destroying hypothalamic hypocretin-producing cells. A definitive cure for narcolepsy is not available to date, and although the research in the field is highly promising, up to now, current treatments have aimed to reduce the symptoms by means of different pharmacological approaches. Moreover, overall narcolepsy symptoms management can also benefit from non-pharmacological approaches such as cognitive behavioral therapies (CBTs) and psychosocial interventions to improve the patients' quality of life in both adult and pediatric-affected individuals as well as the well-being of their families. In this review, we summarize the available therapeutic options for narcolepsy, including the pharmacological, behavioral, and psychosocial interventions.

Narcolepsy and psychosis; case report

Narcolepsy is an infrequent neurological disorder, included in the catalog of rare diseases. Despite the existenceof precise diagnostic criteria, this entity remains underdiagnosed. It is characterized by excessive daytime sleepiness associated with cataplexy; in some cases, hypnagogic or hypnopompic hallucinations, auditory hallucinations, and/or delusional ideation may appear. The occurrence of psychotic symptoms makes differential diagnosis extremely difficult (narcolepsy, schizophrenia, or both). Furthermore, therapeutic management may be complex, since the treatment of one of the disorders may worsen the other. Here we describe the case of a patient with this rare comorbidity, which illustrates the major difficulties associated to both differential diagnosis and therapeutic management once a definitive diagnosis has been reached.

Disease symptomatology and response to treatment in people with idiopathic hypersomnia: initial data from the Hypersomnia Foundation registry

OBJECTIVE/BACKGROUND

Knowledge of idiopathic hypersomnia symptomatology derives from clinical case series. Web-based registries provide complementary information by allowing larger sample sizes, with greater geographic and social diversity.

PATIENTS/METHODS

Data were obtained from the Hypersomnia Foundation's online registry. Common clinical features of idiopathic hypersomnia and other central disorders of hypersomnolence were queried, for the last thirty days and when symptoms were most severe. Symptoms were compared between idiopathic hypersomnia participants with and without long sleep durations and between participants with idiopathic hypersomnia and those with either form of narcolepsy. Frequency of medication use and residual symptoms on medication were evaluated.

RESULTS

Five-hundred sixty-three registry respondents were included, with idiopathic hypersomnia (n = 468), narcolepsy type 2 (n = 44), and narcolepsy type 1 (n = 51). "Brain fog," poor memory, and sleep drunkenness were all present in most idiopathic hypersomnia respondents, with brain fog and sleep drunkenness more commonly endorsed by those with long sleep durations. Eighty-two percent of participants with idiopathic hypersomnia were currently treated with medication, most commonly traditional psychostimulants such as amphetamine salts. Among treated patients, symptoms improved while on medication, but substantial residual hypersomnia symptoms remained. Participants with narcolepsy type 1 were more likely than those with idiopathic hypersomnia to endorse intentional and unintentional daytime naps and automatic behaviors.

CONCLUSIONS

Symptoms of idiopathic hypersomnia extend well beyond excessive daytime sleepiness, and these symptoms frequently persist despite treatment. These findings highlight the importance of online registries in identifying gaps in the use and effectiveness of current treatments.

Efficacy and safety of solriamfetol for excessive daytime sleepiness in narcolepsy and obstructive sleep apnea: a systematic review and meta-analysis of clinical trials

INTRODUCTION

Excessive daytime sleepiness (EDS) is the inability to maintain wakefulness and alertness during the major waking episodes of the day, with sleep occurring unintentionally or at inappropriate times. Solriamfetol is a selective norepinephrine-dopamine reuptake inhibitor approved for EDS. This review was done to assess the efficacy and safety of solriamfetol in patients with EDS in narcolepsy or OSA.

METHODS

A systematic search of the electronic database was conducted for relevant studies. Any randomized controlled trial with outcome measures on the efficacy or safety of solriamfetol in EDS were eligible for inclusion. The primary outcomes were mean difference in the maintenance of wakefulness test (MWT), Epworth sleepiness scale (ESS) score, and risk ratio of adverse events. The random-effects model was used to calculate pooled effect estimates.

RESULTS

We identified 336 records from the database search. We analyzed eight articles reported from six clinical trials. We pooled outcome measures from five trials. The overall mean difference for MWT was 9.93 min (95% CI: 8.25-11.61), and the mean difference of ESS score was -4.44 (95% CI: -5.50 to -3.38), both in favor of solriamfetol over placebo. The overall risk ratio of adverse events with solriamfetol was 1.47 (95% CI: 1.28-1.69). The most common adverse events reported were headache, nausea, decreased appetite, anxiety, nasopharyngitis, and insomnia.

CONCLUSIONS

Solriamfetol is efficacious and has a favorable safety profile in the treatment of EDS in patients with narcolepsy and OSA. Solriamfetol is well tolerated and may be recommended for the treatment of EDS in these patients.

[Advances in treatment of narcolepsy]

Narcolepsy is the most common cause of excessive daytime sleepiness (EDS) following obstructive sleep apnea. Its treatment aims to reduce EDS and cataplexy, improve nighttime sleep disturbance, sleep paralysis and sleep-related hallucinations. Pitolisant (a histamine H3 receptor antagonist) and solriamfetol (a norepinephrine reuptake inhibitor) have recently been approved effective for narcolepsy in the United States and the European Union. Pitolisant has proved to be effective for both EDS and cataplexy. Besides being effective on EDS, solriamfetol seems to have advantages in abuse potential and withdrawal syndrome. As potential treatments for EDS and cataplexy associated with narcolepsy, several new drugs are being developed and tested. These new drugs include new hydroxybutyrate preparations (controlled release sodium hydroxybutyrate FT218, low sodium hydroxybutyrate JZP-258), selective norepinephrine reuptake inhibitor (AXS-12), and modafinil combined with astroglial junction protein inhibitor (THN102). This paper reviews the recently approved drugs and potential treatments for narcolepsy.

GHB concentration in a related post-mortem case

Gamma-hydroxybutyrate (GHB) is a central nervous system depressant, primarily used as a recreational drug of abuse and as a therapeutic substance both in U.S.A. and Europe for the treatment of narcolepsy with cataplexy in adult patients and as adjuvant in the control of alcohol withdrawal syndrome. Several cases of GHB related deaths have been reported in the literature and GHB was found alone or in association to other drugs of abuse. However, only few biological matrices are often analyzed, therefore data on GHB distribution are lacking. Here we report a case involving a 45-year-old man, who was found dead in his bedroom.

Solriamfetol for Excessive Sleepiness in Narcolepsy and Obstructive Sleep Apnea

OBJECTIVE

The purpose of this article is to review the available clinical trial data that led to the Food and Drug Administration (FDA) approval of solriamfetol as well as its role in clinical practice.

DATA SOURCES

A MEDLINE/PubMed search was conducted (January 2000 to February 2020) using the keyword solriamfetol to discover appropriate clinical trials.

STUDY SELECTION AND DATA EXTRACTION

Articles were included that were published in the English language and related to the FDA approval of solriamfetol or provided novel information regarding this drug entity.

DATA SYNTHESIS

The findings of the review show that solriamfetol may be a safe and effective option for the treatment of excessive sleepiness (ES) related to narcolepsy and obstructive sleep apnea (OSA).

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Solriamfetol is distinguished from other stimulants in that it has lower binding affinity to dopamine and norepinephrine transporters and does not have the monoamine-releasing effects of amphetamines at usual therapeutic doses. Because of solriamfetol's unique mechanism of action, there may be a reduction in abuse potential compared with the other currently FDA-approved options.

CONCLUSIONS

In clinical trials, solriamfetol has shown dose-dependent improvement in wakefulness over placebo and adds another option for clinicians when treating ES in narcolepsy and OSA.

Somnolence Preceded the Development of a Subthalamic Lesion in Neuromyelitis Optica Spectrum Disorder

A 67-year-old woman with neuromyelitis optica spectrum disorder (NMOSD) developed severe somnolence. Ten days after admission, fluid-attenuated inversion-recovery magnetic resonance imaging (MRI) revealed hyperintense areas around the bilateral hypothalamus, which were not present on MRI at admission. The orexin level, which is decreased in idiopathic narcolepsy, was slightly decreased in her cerebrospinal fluid. Immunosuppressive treatment and methylphenidate markedly improved her somnolence. This case shows that NMOSD in the acute phase can cause somnolence in a patient without apparent lesions in the hypothalamus.

Pitolisant: A Review in Narcolepsy with or without Cataplexy

Pitolisant (Wakix^®), an orally available, first-in-class antagonist/inverse agonist of the histamine 3 receptor, is approved in the EU (as of March 2016) for the treatment of narcolepsy with or without cataplexy in adults and in the USA (as of August 2019) for the treatment of excessive daytime sleepiness (EDS) in adults with narcolepsy. Pitolisant was demonstrated to have minimal risk of abuse in preclinical and clinical studies, and is the only anti-narcoleptic drug not scheduled as a controlled substance in the USA. The totality of evidence from pivotal and supportive phase III trials suggests that pitolisant administered at up to the recommended maximum dose of 36 mg once daily reduces EDS and cataplexy in adults with narcolepsy relative to placebo. Noninferiority of pitolisant to modafinil in the management of EDS was not demonstrated. Pitolisant was generally well tolerated in clinical trials. Consistent with its mechanism of action, the most common treatment-emergent adverse events included headache, insomnia and anxiety. With minimal abuse potential and offering the convenience of oral, once-daily administration, pitolisant extends the range of approved treatment options available to adult patients with narcolepsy with or without cataplexy.

Recently Approved and Upcoming Treatments for Narcolepsy

Narcolepsy is a chronic, disabling neurologic disorder characterised by excessive daytime sleepiness (EDS) and, in up to 60% of patients, cataplexy. Treatments for narcolepsy are aimed at improving wakefulness (e.g. modafinil, armodafinil, stimulants), reducing cataplexy attacks (e.g. sodium oxybate, venlafaxine), and treating the symptoms of disturbed nocturnal sleep, sleep paralysis and sleep-related hallucinations (e.g. sodium oxybate). In general, medications that increase the release, or inhibit the reuptake, of norepinephrine or dopamine have wake-promoting effects and are useful in managing EDS, whereas medications that inhibit serotonin or norepinephrine reuptake have anticataplectic effects. Modulation of γ-aminobutyric acid B (GABAB) receptors or histamine H3 receptors (H3Rs) has effects on both EDS and cataplexy. Pitolisant, an H3R antagonist, and solriamfetol, a dopamine and norepinephrine reuptake inhibitor, are the most recently approved treatments for EDS associated with narcolepsy in the European Union (pitolisant) and the USA (pitolisant and solriamfetol). Several new agents are being developed and tested as potential treatments for EDS and cataplexy associated with narcolepsy; these agents include novel oxybate formulations (once-nightly [FT218]; low sodium [JZP-258]), a selective norepinephrine reuptake inhibitor (AXS-12), and a product combining modafinil and an astroglial connexin inhibitor (THN102). This review summarises the mechanisms of action, pharmacokinetics, efficacy, and safety/tolerability of recently approved and emerging treatments for narcolepsy.

Effects of Pharmacotherapy Treatment on Patient-Reported Outcomes in a Narcolepsy and Idiopathic Hypersomnia Cohort

STUDY OBJECTIVE

We aimed to evaluate the association between patient-reported outcomes (PROs) and treatment regimen/standardized dose (STD), a measure of drug burden, in patients with narcolepsy type 1 (NT1)/type 2 (NT2) and idiopathic hypersomnia (IH).

METHODS

Patients age 18 years or older with NT1/NT2 and IH with baseline and ≥ 6-month follow-up during 2008-2010 were included. Changes in PROs (Epworth Sleepiness Scale [ESS], Fatigue Severity Scale [FSS], Patient Health Questionnaire 9 [PHQ-9], total sleep time [TST]) by diagnosis, treatment regimen (monotherapy versus polytherapy, sodium oxybate [SO] use), and STD were assessed by t tests and univariable/multivariable linear regressions, adjusting for patient characteristics.

RESULTS

A total of 92 patients (26 [28.3%] NT1, 27 [29.3%] NT2, 39 [42.4%] IH) were included (age 43.8 ± 14.8 years; 66 [71.7%] female). Baseline PROs suggested excessive daytime sleepiness (ESS 14.2 ± 5.2 [74% patients > 10]), significant fatigue (FSS 47.5 ± 12.9), and mild depression (PHQ-9 9.0 [4.0, 14.0] [49.4% ≥ 10]). At follow-up, ESS and PHQ-9 improved significantly overall and within diagnostic, monotherapy/polytherapy, and SO use groups (all P < .01). FSS improved significantly overall (P = .016), but improvements were not significant for IH, monotherapy, polytherapy, and non-SO using groups. In multivariable models, PRO changes were not significantly different between groups, but baseline STD was associated with worsening PHQ-9 across PHQ-9 change models, and ESS worsened with increasing STD at follow-up (P = .056).

CONCLUSIONS

Significant improvements in sleep-related PROs were seen with pharmacotherapy use, regardless of diagnosis or treatment type, highlighting the importance of individualized prescribing decisions for this population.

Pregnancy and Contraception Experiences in Women With Narcolepsy: A Narcolepsy Network Survey

STUDY OBJECTIVES

To explore knowledge and experiences of women with narcolepsy on pregnancy and contraception issues and their relationships with narcolepsy pharmacotherapy.

METHODS

An 18-item survey was administered through the Narcolepsy Network website for 8 weeks during the fall of 2012. The survey ascertained demographic information; prescription narcolepsy medication use and discontinuation during pregnancy; physician counseling regarding pregnancy, contraception, and medication usage; and pregnancy history and outcomes. Frequencies of responses were analyzed and compared between pharmacotherapy groups.

RESULTS

Surveys from 182 women (age 41.5 ± 15.2 years) with narcolepsy were analyzed. Most of the respondents (78.7%) who reported a history of pregnancy did not use pharmacotherapy during pregnancy. Most of them discontinued narcolepsy pharmacotherapy during pregnancy because of their own fear of harming the fetus (82.9%), and 58.5% noted advice of discontinuation from their narcolepsy physician as a factor in their decision. As an alternative to pharmacotherapy, 72.1% of women extended their sleep time, 32.6% discontinued working, and 27.9% discontinued driving. Similar pregnancy and fetal outcomes were reported between women using monotherapy, polytherapy, or no therapy during pregnancy, but some outcomes were worse than national averages. In general, women with narcolepsy were dissatisfied with the amount and type of counseling that they received regarding pregnancy and contraception.

CONCLUSIONS

Improved health education counseling and symptom management options are needed for women with narcolepsy to improve pregnancy management and outcomes in this population.

Decreased body mass index during treatment with sodium oxybate in narcolepsy type 1

Narcolepsy type 1 is characterised by an increase in body weight after disease onset, frequently leading to obesity. It was suggested that this weight gain may be counteracted by treatment with sodium oxybate. We here provide longitudinal body mass index data of patients with narcolepsy type 1 after starting treatment with sodium oxybate, compared with patients in whom treatment with modafinil was initiated. Eighty-one individuals with narcolepsy type 1 fulfilled the entry criteria for this retrospective study: 59 had newly started treatment with sodium oxybate and 22 had newly started modafinil. Gender-specific differences between both treatment groups were compared using Student's t tests and mixed effect modeling. Patients using sodium oxybate lost weight, with a mean body mass index decrease of 2.56 kg/m2 between the first and last measurement (women; p = .001) and 0.84 kg/m2 (men; p = .006). Patients using modafinil, however, gained weight, with a mean body mass index increase of 0.57 kg/m2 (women; p = .033) and 0.67 kg/m2 (men; p = .122). Medication (p = .006) and baseline body mass index (p = .032) were predictors for body mass index decrease. In conclusion, treatment with sodium oxybate is associated with a body mass index reduction in narcolepsy type 1, whereas modafinil treatment is not. This effect is most pronounced in those who already have a higher baseline body mass index.

[Development of a Therapeutic Drug for Narcolepsy]

Narcolepsy-cataplexy is a debilitating disorder characterized by excessive daytime sleepiness and cataplexy, a bilateral loss of muscle tone triggered by positive emotions. The disease is caused by the loss of orexin-producing neurons in the hypothalamus. Currently, only symptom-oriented therapies are available for narcolepsy. We have recently discovered a potent, non-peptide orexin type-2 receptor (OX2R) agonist, YNT-185. We show that peripheral administration of YNT-185 significantly ameliorated the narcolepsy symptoms in a mouse model for narcolepsy. No desensitization was observed after repeated administration of YNT-185 with respect to the suppression of cataplexy-like episodes. These results provide a proof -of-concept for mechanistic therapy for narcolepsy-cataplexy using OX2R agonists. Additionally, YNT-185 promoted wakefulness in wild-type mice, suggesting that orexin receptor agonists may be useful for the treatment of excessive daytime sleepiness due to other conditions, such as sleepiness accompanying depression and sleepiness due to side effects of medicines or jet lag/shift work.

Drugs Used in Narcolepsy and Other Hypersomnias

Narcolepsy and idiopathic hypersomnia cannot be cured; all available treatments are symptomatic. It is of paramount importance for patients, and their relatives, to be informed about the consequences of these chronic diseases and to become ready to accept the consequences of the diagnosis before starting any treatment. This facilitates the implementation of behavioral modifications and the proper use of medication to decrease the disease burden. A supportive social environment (eg, family members, friends, employer, colleagues, and patient support groups) is instrumental. Current treatment options are discussed with a focus on pharmacologic treatment, including future directions.

Case report: narcolepsy type 1 in an adolescent with HIV infection-coincidence or potential trigger?

RATIONALE

Despite the acknowledged importance of environmental risk factors in the etiology of narcolepsy, there is little research on this topic. HIV as a trigger for narcolepsy has not been systematically investigated.

PATIENT CONCERNS

We describe a case of narcolepsy type 1 (NT1) in an adolescent with HIV infection presenting with increased daytime sleepiness and excessive weight gain.

DIAGNOSES

NT1 was diagnosed according to the criteria of the third edition of the International Classification of Sleep Disorders (ICSD-3).

INTERVENTIONS

Pharmacological treatment with methylphenidate.

OUTCOMES

Four months after initiation of methylphenidate therapy the increased daytime sleepiness improved and excessive weight gain stopped.

LESSONS

Diagnosis of NT1 can be challenging at disease onset and is often delayed, especially in the pediatric population, because symptoms usually evolve gradually. The case presented here raises the possibility that the HIV infection may play a role in the pathogenesis of NT1 serving as trigger for autoimmune-mediated destruction of hypocretin-secreting neurons.

The Comorbidity of Focal Epilepsy and Narcolepsy Type 1 - Two Case Reports

The aim of this study is to remind the possibility of co-occurrence of epilepsy and narcolepsy. In the first case report, narcolepsy type 1 was diagnosed in 29-year-old female. After one year of the treatment with modafinil a new episodes of automatic behavior appeared. Patient was reevaluated and the diagnosis of focal epilepsy with partial complex seizures was established. Patient was treated with modafinil and lamotrigine and became seizure-free. In the second case report a 21-year-old female was referred with a typical history of narcolepsy type 1, but also with atypical episodes of gazing and automatic behavior with amnesia for these episodes. Narcolepsy type 1 and focal epilepsy was diagnosed. Some clinical symptoms of narcolepsy (cataplexy, automatic behavior, episodes of sleep attacks) need to be carefully analyzed by EEG and video-EEG not to overlook the epilepsy.

Impact of acute administration of sodium oxybate on heart rate variability in children with type 1 narcolepsy

BACKGROUND

Currently, cardiovascular measurements in children affected with type 1 narcolepsy (NT1) have never been investigated, and neither have their modulation by the administration of sodium oxybate (SO).

METHODS

Twelve drug-naïve NT1 children (four males, eight females) with a mean age of 11 ± 3.16 years underwent a nocturnal polysomnography, at baseline and during the first night of SO administration. Data were contrasted with those recorded in 23 age-matched healthy controls. Heart rate variability (HRV) analysis was performed by analyzing the electrocardiogram signal for automatic detection of R waves with a computer program calculating a series of standard time-domain measures and obtaining spectral parameters, by means of a Fast-Fourier Transform.

RESULTS

In sleep stages N2 and N3, NT1 children showed increased power in the low-frequency (LF) and very-LF (VLF) ranges, when compared to controls. In addition, HRV (as measured by time domain parameters) during all sleep stages tended to be slightly higher in patients when compared to controls. Treatment with SO did not change significantly any parameter, but an overall trend to mildly decreased HRV that reached a significant value only during R sleep.

CONCLUSIONS

HRV during all sleep stages tended to be slightly higher in young patients when compared to controls, confirming the presence of a slight sympathovagal system imbalance even in NT1 children. SO tends to decrease these values especially during REM sleep and in that regard, further studies supporting these preliminary findings and considering the long-term effects of SO on heart rate parameters are warranted.

A Case of Narcolepsy Type 2 and Postural Tachycardia Syndrome Secondary to Lesions of the Thalamus and Amygdala

ABSTRACT

Although there are reports of narcolepsy type 1 caused by lesions of the central nervous system, there are far fewer reports of narcolepsy type 2 (NT2) caused by discrete brain lesions. We report a case of a patient in whom NT2 was diagnosed after a viral illness, and inflammatory lesions in the right thalamus and amygdala were found. In addition, symptoms of autonomic impairment developed and postural tachycardia syndrome was subsequently diagnosed in this patient. To our knowledge this is the first reported case of NT2 resulting from central nervous system lesions in these discrete locations, as well as the first reported case of postural tachycardia syndrome associated with narcolepsy.

Effectiveness and side-effect profile of stimulant therapy as monotherapy and in combination in the central hypersomnias in clinical practice

Effectiveness and side-effect profile data on pharmacotherapy for daytime sleepiness in central hypersomnias are based largely upon randomized controlled trials. Evidence regarding the use of combination therapy is scant. The aim of this study was to examine the effectiveness and occurrence of drug-related side effects of these drugs in routine clinical practice. Adult patients diagnosed with a central hypersomnia during a 54-month period at a tertiary sleep disorders centre were identified retrospectively. Side effects were recorded at every follow-up visit. A total of 126 patients, with 3275 patient-months of drug exposure, were categorized into narcolepsy type 1 (n = 70), narcolepsy type 2 (n = 47) and idiopathic hypersomnia (n = 9). Modafinil was the most common drug used as a first-line treatment (93%) and in combination therapy (70%). Thirty-nine per cent of the patients demonstrated a complete, 25% partial and 36% a poor response to treatment. Combination treatment improved daytime sleepiness in 55% of the patients with residual symptoms despite monotherapy. Sixty per cent of patients reported side effects, and 30% reported treatment-limiting side effects. Drugs had similar side-effect incidence (P = 0.363) and their side-effect profile met those reported in the literature. Twenty-seven per cent of the patients received combination treatment and had fewer side effects compared to monotherapy (29.4% versus 60%, respectively, P = 0.001). Monotherapy appears to achieve satisfactory symptom control in most patients with central hypersomnia, but significant side effects are common. Combination therapy appears to be a useful and safe option in patients with refractory symptoms.

Narcolepsy-cataplexy and psychosis: a case study

AIMS

To report a challenging patient a girl who developed narcolepsyy with cataplexy (NT1) and a psychosis during adolescence. To discuss diagnostic and therapeutic challenges of the comorbid cases.

CASE REPORT

A 14-year-old girl was referred to Sleep and Epilepsy Unit for excessive daytime sleepiness, impaired nocturnal sleep, binge eating and weight gain, over the last year. After being diagnosed with a NT1 the patient was treated with modafinil and sodium oxybate. She was hospitalized for psychotic symptoms after starting NT1 treatment. Withdrawal of the narcolepsy treatment and initiation of haloperidol 1 mg/day (the only antipsychotic treatment she could tolerate) improved the delusions, hallucinations and dysphoria but worsened the narcolepsy symptoms. Polysomnography showed fragmented nocturnal sleep and five sleep REM onset periods in MSLT. Positive HLA-QB1*06:02 and undetectable level of hypocretine in the cerebrospinal fluid were found. MRI and CT-scan were normal. Diagnostic Interview for Genetic Studies Adapted for Narcolepsy (DIGSAN) questionnaire confirmed that patient presented a dual diagnostic NT1 and psychotic symptoms. The last sleep follow-up while on psychopharmacological treatment, showed an increased sleep efficiency index. She currently has severe somnolence, obesity, and partial cataplectic attacks along with normal mood, academic failure and social isolation.

CONCLUSION

The coexistence of narcolepsy with psychoses is a rare clinical entity, more frequent in adolescents than in adults. The comorbidity of the two illnesses worsens clinical and therapeutic prognosis and also suggests interesting pathophysiological hypotheses.