Protriptyline: an effective agent in the treatment of the narcolepsy-cataplexy syndrome and hypersomnia

Vers un élargissement des indications des antidépresseurs

Les données neurochimiques directes ou indirectes obtenues dans différentes affections du système nerveux central (SNC) constituent la base rationnelle de I'utilisation des médicaments dans des indications précises. Les antidépresseurs (AD) tricycliques agissant sur les principales amines du SNC trouvent ainsi des applications thérapeutiques variées en dehors de la dépression. L'arrivée de nouveaux AD au mécanisme d'action, soit plus cibé (la sérotonine), soit différent (IMAO) pose de nouveau cette question des indications psychiatriques et neurologiques, qui ne peut être résolue que par des essais méthodologiquement irréprochables. Une telle approche évitera d'ignorer pendant des années des effets thérapeutiques incontestables d'une molécule ancienne, tel que ce fut le cas de la clomipramine dans les troubles obsessifs-compulsifs.

Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness

The transition from sleep to wake is marked by sleep inertia, a distinct state that is measurably different from wakefulness and manifests as performance impairments and sleepiness. Although the precise substrate of sleep inertia is unknown, electroencephalographic, evoked potential, and neuroimaging studies suggest the persistence of some features of sleep beyond the point of awakening. Forced desynchrony studies have demonstrated that sleep inertia impacts cognition differently than do homeostatic and circadian drives and that sleep inertia is most intense during awakenings from the biological night. Recovery sleep after sleep deprivation also amplifies sleep inertia, although the effects of deep sleep vary based on task and timing. In patients with hypersomnolence disorders, especially but not exclusively idiopathic hypersomnia, a more pronounced period of confusion and sleepiness upon awakening, known as "sleep drunkenness", is common and problematic. Optimal treatment of sleep drunkenness is unknown, although several medications have been used with benefit in small case series. Difficulty with awakening is also commonly endorsed by individuals with mood disorders, disproportionately to the general population. This may represent an important treatment target, but evidence-based treatment guidance is not yet available.

Pharmacotherapy options for cataplexy

INTRODUCTION

Narcolepsy with cataplexy is a rare disabling sleep disorder characterized by two major symptoms: excessive daytime sleepiness and cataplexy characterized by a sudden bilateral loss of voluntary muscular tone triggered by strong positive emotional factors. Pathophysiological studies have shown that the disease is caused by the early loss of hypothalamic hypocretin neurons.

AREAS COVERED

Following a literature search on PubMed using "narcolepsy," "cataplexy," "treatment," "medication," and "drug" as keywords, we critically analyzed and reviewed current evidence about optimal management of cataplexy in humans. The management of cataplexy has evolved over the past few years with the widespread use of antidepressants, especially those with adrenergic uptake inhibitor properties and gamma-hydroxybutyrate (sodium oxybate).

EXPERT OPINION

Based on class 1 evidence studies, first-line pharmacological treatment of cataplexy should be sodium oxybate. Second-line treatment should be antidepressants with norepinephrine/serotonine reuptake inhibitor venlafaxine based on its good benefit-risk ratio; however, this recommendation lacks class 1 evidence and is based on expert opinion only. Given the major developments in understanding the neurobiological basis of cataplexy, future therapeutic targets are clearly oriented toward immune-based therapies at early stages of the disease and hypocretin replacement therapy.

Obstructive sleep apnea syndrome: from phenotype to genetic basis

Obstructive sleep apnea syndrome (OSAS) is a complex chronic clinical syndrome, characterized by snoring, periodic apnea, hypoxemia during sleep, and daytime hypersomnolence. It affects 4-5% of the general population. Racial studies and chromosomal mapping, familial studies and twin studies have provided evidence for the possible link between the OSAS and genetic factors and also most of the risk factors involved in the pathogenesis of OSAS are largely genetically determined. A percentage of 35-40% of its variance can be attributed to genetic factors. It is likely that genetic factors associated with craniofacial structure, body fat distribution and neural control of the upper airway muscles interact to produce the OSAS phenotype. Although the role of specific genes that influence the development of OSAS has not yet been identified, current researches, especially in animal model, suggest that several genetic systems may be important. In this chapter, we will first define the OSAS phenotype, the pathogenesis and the risk factors involved in the OSAS that may be inherited, then, we will review the current progress in the genetics of OSAS and suggest a few future perspectives in the development of therapeutic agents for this complex disease entity.

Antidepressant drugs for narcolepsy

BACKGROUND

Narcolepsy is a disorder of the central nervous system, the main symptoms of which are excessive daytime sleepiness (EDS) and cataplexy (an abrupt and reversible decrease in or loss of muscle tone, affecting the limbs or trunk or both, elicited by emotional stimuli). Narcolepsy has an adverse impact on people's quality of life. Together with stimulant drugs (used to control EDS), antidepressants are usually recommended to counteract cataplexy. In addition, some antidepressants are also reported to improve EDS.

OBJECTIVES

To evaluate the effects of antidepressant drugs on EDS, cataplexy, quality of life, and their side effects in people with narcolepsy.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2007), MEDLINE (1966 to 2007), EMBASE (1980 to 2007), PsycINFO (1872 to 2007), and CINAHL (1981 to 2007). Bibliographies of identified articles were reviewed to find additional references. Unpublished randomised trials were searched for by consulting governmental and non-governmental clinical trial registers, disease-specific websites, investigators and experts in the field, pharmaceutical companies/manufacturers.

SELECTION CRITERIA

Parallel or cross-over randomised or quasi-randomised controlled trials testing the treatment of narcolepsy with any type of antidepressant drug versus no treatment, placebo, or another antidepressant drug.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

Three cross-over and two parallel trials were included with a total of 246 participants. The methodological quality of all studies was unclear. As the trials tested different comparisons, or had a different design or dealt with different outcome measures, meta-analysis was not performed. In one cross-over trial (10 participants) femoxetine had no significant effect in eliminating or reducing EDS but significantly reduced cataplexy. Mild and transient side effects were reported in the femoxetine treatment period by two participants. In a second cross-over trial (56 participants) viloxazine significantly reduced EDS and cataplexy. In a third cross-over trial the authors inappropriately treated the trial design as a parallel study and no conclusions can be reached in favour of either drug. Two more trials with parallel design tested ritanserin versus placebo without finding differences of effectiveness in reducing EDS or cataplexy.

AUTHORS' CONCLUSIONS

There was no good quality evidence that antidepressants are effective for narcolepsy or improve quality of life. Despite the clinical consensus recommending antidepressants for cataplexy there is scarce evidence that antidepressants have a positive effect on this symptom. There is a clear need for well-designed randomised controlled trials to assess the effect of antidepressants on narcolepsy.

Clinical and neurobiological aspects of narcolepsy

Narcolepsy is characterized by excessive daytime sleepiness (EDS), cataplexy and/or other dissociated manifestations of rapid eye movement (REM) sleep (hypnagogic hallucinations and sleep paralysis). Narcolepsy is currently treated with amphetamine-like central nervous system (CNS) stimulants (for EDS) and antidepressants (for cataplexy). Some other classes of compounds such as modafinil (a non-amphetamine wake-promoting compound for EDS) and gamma-hydroxybutyrate (GHB, a short-acting sedative for EDS/fragmented nighttime sleep and cataplexy) given at night are also employed. The major pathophysiology of human narcolepsy has been recently elucidated based on the discovery of narcolepsy genes in animals. Using forward (i.e., positional cloning in canine narcolepsy) and reverse (i.e., mouse gene knockout) genetics, the genes involved in the pathogenesis of narcolepsy (hypocretin/orexin ligand and its receptor) in animals have been identified. Hypocretins/orexins are novel hypothalamic neuropeptides also involved in various hypothalamic functions such as energy homeostasis and neuroendocrine functions. Mutations in hypocretin-related genes are rare in humans, but hypocretin-ligand deficiency is found in many narcolepsy-cataplexy cases. In this review, the clinical, pathophysiological and pharmacological aspects of narcolepsy are discussed.

EFNS guidelines on management of narcolepsy

Management of narcolepsy with or without cataplexy relies on several classes of drugs, namely stimulants for excessive daytime sleepiness and irresistible episodes of sleep, antidepressants for cataplexy and hypnosedative drugs for disturbed nocturnal sleep. In addition, behavioral measures can be of notable value. Guidelines on the management of narcolepsy have already been published. However contemporary guidelines are necessary given the growing use of modafinil to treat excessive daytime sleepiness in Europe within the last 5-10 years, and the decreasing need for amphetamines and amphetamine-like stimulants; the extensive use of new antidepressants in the treatment of cataplexy, apart from consistent randomized placebo-controlled clinical trials; and the present re-emergence of gamma-hydroxybutyrate under the name sodium oxybate, as a treatment of all major symptoms of narcolepsy. A task force composed of the leading specialists of narcolepsy in Europe has been appointed. This task force conducted an extensive review of pharmacological and behavioral trials available in the literature. All trials were analyzed according to their class evidence. Recommendations concerning the treatment of each single symptom of narcolepsy as well as general recommendations were made. Modafinil is the first-line pharmacological treatment of excessive daytime sleepiness and irresistible episodes of sleep in association with behavioral measures. However, based on several large randomized controlled trials showing the activity of sodium oxybate, not only on cataplexy but also on excessive daytime sleepiness and irresistible episodes of sleep, there is a growing practice in the USA to use it for the later indications. Given the availability of modafinil and methylphenidate, and the forseen registration of sodium oxybate for narcolepsy (including excessive daytime sleepiness, cataplexy, disturbed nocturnal sleep) in Europe, the place of other compounds will become fairly limited. Since its recent registration cataplexy sodium oxybate has now become the first-line treatment of cataplexy. Second-line treatments are antidepressants, either tricyclics or newer antidepressants, the later being increasingly used these past years despite few or no randomized placebo-controlled clinical trials. As for disturbed nocturnal sleep the best option is still hypnotics until sodium oxybate is registered for narcolepsy. The treatments used for narcolepsy, either pharmacological or behavioral, are diverse. However the quality of the published clinical evidences supporting them varies widely and studies comparing the efficacy of different substances are lacking. Several treatments are used on an empirical basis, specially antidepressants for cataplexy, due to the fact that these medications are already used widely in depressed patients, leaving little motivation from the manufacturers to investigate efficacy in relatively rare indications. Others, in particular the more recently developed substances, such as modafinil or sodium oxybate, are evaluated in large randomized placebo-controlled trials. Our objective was to reinforce the use of those drugs evaluated in randomized placebo-controlled trials and to reach a consensus, as much as possible, on the use of other available medications.

Molecular genetics and treatment of narcolepsy

Narcolepsy is a neurological disorder characterized by excessive daytime sleepiness and cataplexy. The hypocretin/orexin deficiency is likely to be the key to its pathophysiology in most of cases although the cause of human narcolepsy remains elusive. Acting on a specific genetic background, an autoimmune process targeting hypocretin neurons in response to yet unknown environmental factors is the most probable hypothesis in most cases of human narcolepsy with cataplexy. Although narcolepsy presents one of the tightest associations with a specific human leukocyte antigen (HLA) (DQB1*0602), there is strong evidence that non-HLA genes also confer susceptibility. In addition to a point mutation in the prepro-hypocretin gene discovered in an atypical case, a few polymorphisms in monoaminergic and immune-related genes have been reported associated with narcolepsy. The treatment of narcolepsy has evolved significantly over the last few years. Available treatments include stimulants for hypersomnia with the quite recent widespread use of modafinil, antidepressants for cataplexy, and gamma-hydroxybutyrate for both symptoms. Recent pilot open trials with intravenous immunoglobulins appear an effective treatment of cataplexy if applied at early stages of narcolepsy. Finally, the discovery of hypocretin deficiency might open up new treatment perspectives.

Antidepressant drugs for narcolepsy

BACKGROUND

Narcolepsy is a disorder of the central nervous system, the main symptoms of which are excessive daytime sleepiness (EDS) and cataplexy (an abrupt and reversible decrease in or loss of muscle tone, affecting the limbs and/or trunk, elicited by emotional stimuli). Narcolepsy has an adverse impact on people's quality of life. Together with stimulant drugs (used to control EDS), antidepressants are usually recommended to counteract cataplexy. In addition, some antidepressants are also reported to improve EDS.

OBJECTIVES

To evaluate the effects of antidepressant drugs on EDS, cataplexy, quality of life, and their side effects in people with narcolepsy.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to 2003), EMBASE (1980 to 2003), PsycINFO (1872 to 2003), and CINAHL (1981 to 2003). Bibliographies of identified articles were reviewed to find additional references. Unpublished randomised trials were searched for by consulting governmental and non-governmental clinical trial registers, disease-specific websites, investigators and experts in the field, pharmaceutical companies/manufacturers.

SELECTION CRITERIA

Parallel or cross-over randomised or quasi-randomised controlled trials testing the treatment of narcolepsy with any type of antidepressant drug versus no treatment, placebo, or another antidepressant drug.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials for inclusion and extracted data. Outcomes were: (a) elimination of EDS; (b) mean reduction of EDS; (c) elimination of cataplexy; (d) 50% or greater reduction in cataplexy frequency; (e) mean reduction of cataplexy; (f) mean improvement in quality of life; (g) adverse events; (h) withdrawal from treatment.

MAIN RESULTS

Two cross-over trials were included. The methodological quality of both studies was unclear and so the influence of common biases was impossible to define. As the trials tested two different comparisons (one femoxetine versus placebo, the other fluvoxamine versus clomipramine) meta-analysis was not performed. In the first trial (10 participants) femoxetine had no significant effect in eliminating or reducing EDS; a significant reduction of cataplexy was in favour of femoxetine. Mild and transient side effects were reported in the femoxetine treatment period by two participants. In the second trial the authors inappropriately treated the trial design as a parallel study and no conclusions can be reached in favour of either drug.

AUTHORS' CONCLUSIONS

There was no good quality evidence that antidepressants are effective for narcolepsy or improve quality of life. Despite the clinical consensus recommending antidepressants for cataplexy there is scarce evidence that antidepressants have a positive effect on this symptom. There is a clear need for well-designed randomised controlled trials to assess the effect of antidepressants on narcolepsy.

Pharmacotherapy for cataplexy

A variety of medications representing several major drug classes improve cataplexy in patients with narcolepsy. These include aminergic reuptake inhibitors such as venlafaxine and clomipramine as well as sodium oxybate. This review is intended to familiarize readers with the safety and efficacy of these medications, thus enabling clinicians to optimize their management of cataplexy.

Narcolepsy in the older adult: epidemiology, diagnosis and management

Narcolepsy is a disorder of impaired expression of wakefulness and rapid-eye-movement (REM) sleep. This manifests as excessive daytime sleepiness and expression of individual physiological correlates of REM sleep that include cataplexy and sleep paralysis (REM sleep atonia intruding into wakefulness), impaired maintenance of REM sleep atonia (e.g. REM sleep behaviour disorder [RBD]), and dream imagery intruding into wakefulness (e.g. hypnagogic and hypnopompic hallucinations). Excessive sleepiness typically begins in the second or third decade followed by expression of auxiliary symptoms. Only cataplexy exhibits a high specificity for diagnosis of narcolepsy. While the natural history is poorly defined, narcolepsy appears to be lifelong but not progressive. Mild disease severity, misdiagnoses or long delays in cataplexy expression often cause long intervals between symptom onset, presentation and diagnosis. Only 15-30% of narcoleptic individuals are ever diagnosed or treated, and nearly half first present for diagnosis after the age of 40 years. Attention to periodic leg movements (PLM), sleep apnoea and RBD is particularly important in the management of the older narcoleptic patient, in whom these conditions are more likely to occur. Diagnosis requires nocturnal polysomnography (NPSG) followed by multiple sleep latency testing (MSLT). The NPSG of a narcoleptic patient may be totally normal, or demonstrate the patient has a short nocturnal REM sleep latency, exhibits unexplained arousals or PLM. The MSLT diagnostic criteria for narcolepsy include short sleep latencies (<8 minutes) and at least two naps with sleep-onset REM sleep. Treatment includes counselling as to the chronic nature of narcolepsy, the potential for developing further symptoms reflective of REM sleep dyscontrol, and the hazards associated with driving and operating machinery. Elderly narcoleptic patients, despite age-related decrements in sleep quality, are generally less sleepy and less likely to evidence REM sleep dyscontrol. Nonpharmacological management also includes maintenance of a strict wake-sleep schedule, good sleep hygiene, the benefits of afternoon naps and a programme of regular exercise. Thereafter, treatment is highly individualised, depending on the severity of daytime sleepiness, cataplexy and sleep disruption. Wake-promoting agents include the traditional psychostimulants. More recently, treatment with the 'activating' antidepressants and the novel wake-promoting agent modafinil has been advocated. Cataplexy is especially responsive to antidepressants which enhance synaptic levels of noradrenaline (norepinephrine) and/or serotonin. Obstructive sleep apnoea and PLMs are more common in narcolepsy and should be suspected when previously well controlled older narcolepsy patients exhibit a worsening of symptoms. The discovery that narcolepsy/cataplexy results from the absence of neuroexcitatory properties of the hypothalamic hypocretin-peptidergic system will significantly advance understanding and treatment of the symptom complex in the future.

Clinical aspects and pathophysiology of narcolepsy

Narcolepsy is a chronic debilitating sleep disorder first described in the late 19th century. It is characterized by two major symptoms, excessive daytime sleepiness and cataplexy, and two so-called auxiliary symptoms, hypnagogic hallucinations and sleep paralysis. The final diagnosis relies on polysomnography showing the presence of sleep onset rapid eye movement periods (SOREMPs) during the multiple sleep latency test. The presence of HLA DQA1*0102-DQB1*0602 is supportive of the diagnosis. The pathophysiology of the disorder is still unknown but an imbalance between monoamines and acetylcholine is generally accepted. Recent findings in narcoleptic dogs, a natural model of narcolepsy, and in knockout mice revealed that a mutation of type 2 hypocretin receptor plays a major role in the etiology of narcolepsy. Up to now, no mutation has been found in humans except a case of early onset and atypical narcolepsy. However, a marked reduction of hypocretin type 1 has been found in the cerebrospinal fluid (CSF) of a majority of patients and a global loss of hypocretins was noted in post-mortem brain tissue of narcoleptic subjects. Conversely, no hypocretin neuron degeneration has been observed in the genetic form of narcolepsy in dogs but no trace of hypocretin was seen in the brain or the CSF in cases of sporadic canine narcolepsy. This suggests that different hypocretinergic mechanisms are involved in sporadic and genetic forms of canine narcolepsy. Treatment has not evolved significantly over the last few years. However, new drugs, such as hypocretin agonists, are currently being developed.

SIGNIFICANCE

After the discovery of the type 2 hypocretin receptor mutation in canine narcolepsy and the finding of a CSF hypocretin-1 deficiency in human narcolepsy, the major stream of research has involved the hypocretinergic system. However, other lines of research deserve to be pursued simultaneously, in view of comprehensive advancements in the understanding of narcolepsy.

Treatment options for sleep apnoea

Sleep apnoea (SA) is a common sleep disorder affecting 4 to 25% of the adult population. The most common form, obstructive SA, is characterised by recurrent upper airway obstruction during sleep associated with sleep disruption and hypoxaemia. There is increasing evidence that SA leads to impaired vigilance, quality of life, driving accidents and probably represents a vascular disease risk factor. Currently, the most effective treatments are aimed at increasing upper airway space by either air pressure [(continuous positive airway pressure (CPAP)], upper airway surgery or oral appliances. CPAP is the main treatment modality for moderate to severe SA but noncompliance approaches 50% in clinic populations. A number of pharmacological agents have been used in SA but at this stage, none are indicated in moderate to severe SA.

Narcolepsy: genetic predisposition and neuropharmacological mechanisms. REVIEW ARTICLE

Narcolepsy is a disabling sleep disorder characterized by excessive daytime somnolence (EDS), cataplexy and REM sleep-related abnormalities. It is a frequently-occurring but under-diagnosed condition that affects 0.02 to 0.18% of the general population in various countries. Although most cases occur sporadically, familial clustering may be observed; the risk of a first-degree relative of a narcoleptic developing narcolepsy is 10-40 times higher than in the general population. The disorder is tightly associated with the specific human leukocyte antigen (HLA) allele, DQB1*0602 [most often in combination with HLA-DR2 (DRB1*15)]. Genetic transmission is, however, likely to be polygenic in most cases, and genetic factors other than HLA-DQ are also likely to be implicated. In addition, environmental factors are involved in disease predisposition; most monozygotic twins pairs reported in the literature are discordant for narcolepsy. Narcolepsy was reported to exist in canines in the early 1970s. Both sporadic and familial cases are also observed in this animal species. A highly-penetrant single autosomal recessive gene, canarc-1, is involved in the transmission of narcolepsy in Doberman pinschers and Labrador retrievers. Positional cloning of this gene is in progress, and a human homologue of this gene, or a gene with a functional relationship to canarc-1, might be involved in some human cases. Human narcolepsy is currently treated with central nervous system (CNS) stimulants for EDS and antidepressants for cataplexy and abnormal REM sleep. These treatments are purely symptomatic and induce numerous side effects. These compounds disturb nocturnal sleep in many patients, and tolerance may develop as a result of continuous treatment. The canine model is an invaluable resource for studying the pharmacological and physiological control of EDS and cataplexy. Experiments using canine narcolepsy have demonstrated that increased cholinergic and decreased monoaminergic transmission are likely to be at the basis of the pathophysiology of the disorder. Pharmacological studies have shown that blockade of norepinephrine uptake mediates the anticataplectic effect of currently prescribed antidepressants, while blockade of dopamine uptake and/or stimulation of dopamine release mediates the awake-promoting effect of CNS stimulants. Studies in canine narcolepsy also suggest that mechanisms and brain sites for triggering cataplexy are not identical to those regulating REM sleep. It may thus be possible to develop new pharmacological compounds that specifically target abnormal symptoms in narcolepsy, but do not disturb physiological sleep/wake cycles. (See also postscript remarks).

Pharmacological aspects of human and canine narcolepsy

Narcolepsy-cataplexy is a disabling neurological disorder that affects 1/2000 individuals. The main clinical features of narcolepsy, excessive daytime sleepiness and symptoms of abnormal REM sleep (cataplexy, sleep paralysis, hypnagogic hallucinations) are currently treated using amphetamine-like compounds or modafinil and antidepressants. Pharmacological research in the area is facilitated greatly by the existence of a canine model of the disorder. The mode of action of these compounds involves presynaptic activation of adrenergic transmission for the anticataplectic effects of antidepressant compounds and presynaptic activation of dopaminergic transmission for the EEG arousal effects of amphetamine-like stimulants. The mode of action of modafmil is still uncertain, and other neurochemical systems may offer interesting avenues for therapeutic development. Pharmacological and physiological studies using the canine model have identified primary neurochemical and neuroanatomical systems that underlie the expression of abnormal REM sleep and excessive sleepiness in narcolepsy. These involve mostly the pontine and basal forebrain cholinergic, the pontine adrenergic and the mesolimbic and mesocortical dopaminergic systems. These studies confirm a continuing need for basic research in both human and canine narcolepsy, and new treatments that act directly at the level of the primary defect in narcolepsy might be forthcoming.

Treatment of narcolepsy-cataplexy syndrome with the new selective and reversible MAO-A inhibitor brofaromine-a pilot study

Eighteen narcoleptic patients were treated in a single-blind study with brofaromine, a new selective and reversible MAO-A-inhibitor. After a drug-free period of seven days, brofaromine was administered for two weeks. Patients were treated with 75 mg brofaromine for the first week and with 150 mg brofaromine for the second week of the study. After an adaptation night nocturnal sleep EEGs were recorded under placebo before brofaromine was given, one week later under 75 mg, and another week later under 150 mg brofaromine. Excessive daytime sleepiness (EDS) was evaluated under placebo at the beginning of the study, under 75 mg at the end of the first week, and under 150 mg brofaromine at the end of the second week by means of the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT). The number of cataplexies was protocolled by the patients. Compared to placebo the administration of 150 mg brofaromine led to a significant increase of sleep latency in the MLST as well as in the MWT. REM sleep was significantly suppressed in the nocturnal sleep EEG, in the MSLT and in the MWT. The number of cataplexies protocolled by the patient was significantly decreased under 150 mg of brofaromine compared to placebo. Improvement of vigilance and cataplexy occurred in dose-dependent manner. No serious side effects were observed. The results of the present single-blind study indicate that brofaromine seems to be a well-tolerated and effective drug for the treatment of excessive daytime sleepiness and cataplexy in narcoleptic patients.

Protriptyline as an alternative stimulant medication in patients with brain injury: a series of case reports

The results of a series of eight individual case reports in which protriptyline, an activating tricyclic antidepressant, was used as a 'stimulant' medication are presented. For some patients with head injury, traditional stimulants, such as methylphenidate, or dopaminergic stimulants, such as levodopa-carbidopa, amantadine, or bromocriptine, may be partially or totally ineffective or not tolerated. Protriptyline can be a very effective alternative and, for some patients, may be the most effective stimulant tried. In low to moderate doses, protriptyline should be considered for trials as an activating/stimulant medication in patients with head injury.

Response of obstructive sleep apnea to fluoxetine and protriptyline

Protripyline is the pharmacologic agent most commonly used to treat obstructive sleep apnea (OSA); however, its anticholinergic side effects make it intolerable to many patients. Because serotonin may be a central respiratory stimulant and because the serotonin-uptake inhibitor, fluoxetine, is usually well tolerated, we wanted to try fluoxetine in the treatment of OSA. Therefore, we compared the effect of fluoxetine to that of protriptyline in 12 patients with OSA. Both drugs significantly decreased the proportion of REM sleep time and decreased the number of apneas or hypopneas in NREM sleep. The response to fluoxetine was equivalent to that of protriptyline; however, for the group as a whole, there was no significant improvement in the number of arterial oxygen desaturation events, the level of arterial oxygen desaturation, or the number of arousals with either agent. Although there was wide variability in the response to each medication, six of the 12 patients had good responses, including improvement in oxygenation, to either fluoxetine or protriptyline. Three patients could not complete the trial of protriptyline. We conclude that fluoxetine is beneficial to some, but not all, patients with OSA. Fluoxetine was better tolerated than protriptyline.

Neurochemical perspectives of the narcoleptic syndrome

Narcolepsy has been defined as a disorder of excessive sleep often associated with cataplexy, sleep paralysis and hypnagogic hallucinations. Although the pathophysiology of the narcoleptic syndrome is not well understood, derangement in the functions of CNS catecholamines and serotonin (5-HT) have been implicated. In the present paper we summarize evidence to suggest a role for the endogenous opioids in the regulation of normal sleep and in the pathophysiology of the narcoleptic syndrome.

Medical therapy of obstructive sleep apnea

Guidelines for the medical therapy of obstructive sleep apnea are difficult to define precisely. While some elegant investigations have been completed, most study populations have been small. Also, the long-term effects of most forms of therapy are not known. Some patients will respond to a given form of therapy or combination of therapies while others will not. In most instances the responders cannot be recognized prior to the institution of therapy and a cycle of trial and error ensues. One of the best nonsurgical approaches appears to be weight loss, albeit unsuccessful in most cases. Almost all experts would agree, however, that in nonemergent situations weight loss should be strongly suggested. Nasal CPAP appears to be the single most promising device. Protriptyline may have a role, although in our opinion its true efficacy remains to be determined. Oxygen will probably serve more an adjunctive role in therapy, and medroxyprogesterone appears to be beneficial only in the treatment of the obesity-hypoventilation syndrome. A reasonable approach to the medical treatment of the obstructive sleep apnea patient should include, first, by history, physical examination, and appropriate laboratory testing, elimination of anatomically correctable, pharmacologic, or endocrinologic causes of OSA. If apnea length, degree of desaturation, cardiac arrhythmias, or levels of hypersomnolence are so severe as to be potentially life threatening, immediate tracheostomy is suggested. In specialized centers, nasal CPAP would be used. In less severely affected patients, medical management, as discussed above, should begin. We believe that in view of the lack of controlled trials demonstrating which form of therapy is best, the clinician must recommend therapy on the basis of local clinical experience and patient acceptance. Of fundamental importance is the need for serial reevaluation so that the impact of therapeutic failure can be minimized.

Antidepressants: a clinical update for medical practitioners

Knowledge of the pharmacologic actions of antidepressants enables the physician to develop an appropriate rationale for the use of these medications in the medical setting. The appropriate choice of drug and adequate dose, duration, maintenance, termination, therapy, and alternatives should be considered.

Sleep apnea

Sleep apnea is characterized by recurrent upper airway obstruction, resulting in periodic apneic episodes that are associated with oxygen desaturation and frequent awakenings. This leads to daytime somnolence and, possibly, pulmonary hypertension and cor pulmonale. Tracheostomy has been the standard treatment for severe sleep apnea with life-threatening complications. Several recent studies have reported benefits of protriptyline in obstructive sleep apnea. The drug does not completely resolve the apnea, but does improve nocturnal oxygenation and reduce daytime hypersomnolence. Protriptyline should be considered an alternative to tracheostomy in patients with benign or moderately severe obstructive sleep apnea.

Protriptyline in obstructive sleep apnea: a double-blind trial

We evaluated protriptyline, a nonsedating tricyclic antidepressant, as a treatment for obstructive sleep apnea in a double-blind crossover study of five men. After two weeks of treatment, with no change in body weight, daytime somnolence was markedly reduced and nocturnal oxygenation was improved, although apnea duration and frequency were not significantly decreased. Rapid-eye-movement (REM) stage time as a fraction of the total sleep time was reduced during treatment from 0.231 +/- 0.031 to 0.107 +/- 0.013 (mean +/- S.E.M.) (P less than 0.05). REM apnea time as a fraction of total sleep time was reduced from 0.145 +/- 0.022 to 0.054 +/- 0.006 (P less than 0.05). REM reduction during treatment with protriptyline can account for decreased REM apnea time. Similar decreases in REM stage time and REM apnea duration and similar improvement in oxygenation continued after six months of treatment. In addition, body weight, apnea, and arousal frequency were decreased at this time. Although the obstructive sleep apnea was not resolved, it was reduced. Protriptyline can be effective in patients with sleep apnea when the disorder is not life-threatening.

Protriptyline in the treatment of sleep apnoea

Nine patients with obstructive sleep apnoea were treated with 5 to 20 mg of protriptyline each night for two to 18 months. In four patients, there was dramatic, sustained improvement in symptoms and measured sleep quality and apnoea frequency and duration. There was no improvement in two patients and three developed intolerable side-effects preventing adequate treatment. Apnoea frequency was the only apparent predictor of responsiveness. Those with fewer than 30 episodes of apnoea per hour consistently improved. Only two of four patients with more than 60 episodes per hour improved. These results provide additional evidence that a carefully monitored trial of protriptyline may benefit selected patients with mild to moderate obstructive sleep apnoea.

The treatment of narcolepsy and cataplexy

Narcolepsy may affect as many as 250,000 Americans. It involves a neurologic defect in the regulation of sleep and wakefulness. The chief symptoms are sleepiness, inappropriate sleep episodes, and cataplexy. Narcoleptic patients also frequently complain of hypnagogic hallucinations, sleep paralysis, and automatic behavior, as well as disturbed nocturnal sleep. Narcolepsy usually develops in adolescence and is a life-long illness. Satisfactory treatment is not available at the present time. The current treatments of choice include general measures (such as patient and family counseling and frequent napping) and drug treatments, including methylphenidate for sleepiness and sleep episodes and imipramine for cataplexy. Medication dosages mut be adjusted for individual patients. Pharmacists have a special responsibility to monitor narcoleptic patients by becoming familiar with the disease and its symptoms and by encouraging patients to follow their drug regimens and to take drug holidays under the supervision of the physician when the drug dose becomes excessive.

An etiology of narcolepsy-cataplexy and a proposed cataplexy neuromechanism

Narcolepsy-cataplexy is an idiopathic sleep disorder that reflects a complex neuropathology. Surveys and physiological investigations indicate that genetic and stress factors are involved in its onset and that stress is associated with symptomatic fluctuations and exacerbations of its clinical course. This paper summarizes the literature regarding the evolution, characteristics and treatment of the disorder. A comprehensive etiology is advanced, integrating neurophysiological and psychological factors specific to narcolepsy-cataplexy with recent advances in blood pressure regulation. Moreover, a testable neuromechanism of cataplexy is proposed, based on longitudinal effects of chronic drowsiness, the strong hypnogenic effect obtained by carotid sinus stimulation, an experimental animal model of narcolepsy-cataplexy, the adaptive characteristics of baroreceptors and, finally, the interconnections between CNS sleep and blood pressure regulators of the brain stem. Through better understanding of the causes and mechanisms of narcolepsy-cataplexy, more effective treatments and preventive measures can be developed, high risk populations identified, and, perhaps, a cure found. Suggestions for future physiological and epidemiological research are made.

Fluvoxamine and clomipramine in the treatment of cataplexy

Fluvoxamine 25-200 mg daily and clomipramine 25-200 mg daily were given for separate three week periods to 18 subjects with narcolepsy and cataplexy. Both drugs improved cataplexy but not narcolepsy. Fluvoxamine was less active than clomipramine, but both drugs abolished cataplexy in individual subjects. Gastrointestinal side effects prevented treatment with fluvoxamine in five subjects. All patients completed the clomipramine phase of the trial, but two men complained of delayed ejaculation. Fluvoxamine is a more potent inhibitor of 5-hydroxytryptamine (5-HT) reuptake in some systems, but not in others. It is therefore uncertain whether the greater anticataplectic effect of clomipramine is due to a greater inhibition of 5-HT reuptake or to other mechanisms.