Narcolepsy. Signs, symptoms, differential diagnosis, and management

Therapeutic effects of Delta9-THC and modafinil in a marmoset Parkinson model

Current therapies for Parkinson's disease (PD) like l-dopa and dopamine (DA) agonists have declined efficacy after long term use. Therefore, research towards supplementary or alternative medication is needed. The implementation in PD can be expedited by application of compounds already used in the clinic. In this study the therapeutic effects of the psychoactive compounds Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and modafinil were tested in the 1-methyl-1,2,3,6-tetrahydropyridine (MPTP)-marmoset model for PD. The anti-parkinson effects of Delta(9)-THC (4 mg/kg) and modafinil (100 mg/kg) in parkinsonian marmosets were assessed with two behavioral rating scales covering parkinsonian symptoms and involuntary movements and two test systems assessing the locomotor activity and hand-eye coordination. Delta(9)-THC improved activity and hand-eye coordination, but induced compound-related side-effects. Modafinil improved activity and observed parkinsonian symptoms but not hand-eye coordination. It can be concluded that both compounds have therapeutic values and could supplement existing therapies for PD.

Comparative analysis of multiple sleep latency tests (MSLT) parameters and occurrence of dreaming in patients with daytime sleepiness of narcoleptic and non-narcoleptic origin

OBJECTIVE

To compare MSLT parameters in two groups of patients with daytime sleepiness, correlated to the occurrence and onset of dreams.

METHOD

Patients were submitted to the MSLT between January/1999 and June/2002. Sleep onset latency, REM sleep latency and total sleep time were determined. The occurrence of dreams was inquired following each MSLT series. Patients were classified as narcoleptic (N) or non-narcoleptic (NN).

RESULTS

Thirty patients were studied, 12 were classified as narcoleptics (N group; 40%), while the remaining 18 as non-narcoleptic (NN group; 60%). Thirty MSLT were performed, resulting in 146 series. Sleep was detected in 126 series (86%) and dreams in 56 series (44.44%). Mean sleep time in the N group was 16.0+/-6.3 min, while 10.5+/-7.5 min in the NN group (p<0.0001). Mean sleep latency was 2.0+/-2.2 min and 7.2+/-6.0 min in the N and NN group, respectively (p<0.001). Mean REM sleep latency in the N group was 3.2+/-3.1min and 6.9+/-3.7 min in the NN group (p=0.021). Dreams occurred in 56.9% of the N group series and 28.4% in that of the NN group (p=0.0009). Dream frequency was detected in 29.8% and 75% of the NREM series of the N and NN groups, respectively (p=0.0001).

CONCLUSION

Patients from the N group, compared to the NN group, slept longer and earlier, demonstrated a shorter REM sleep onset and greater dream frequency. NN patients had a greater dream frequency in NREM series. Thus, the occurrence of dreams during NREM in the MSLT may contribute to differentially diagnose narcolepsy and daytime sleepiness.

Sleep paralysis among Cambodian refugees: association with PTSD diagnosis and severity

Among Cambodian refugees attending a psychiatric clinic (n=100), 49% (49/100) had at least one episode of sleep paralysis (SP) in the previous 12 months. The annual and monthly SP prevalences were much higher in posttraumatic stress disorder (PTSD) than in non-PTSD patients. Among the PTSD patients, 65% (30/46) had monthly episodes of SP versus 14.85% (8/54) among non-PTSD patients (chi2[2, n=100]=26.78, P<.001). Moreover, patients with SP in the last month (n=30) versus those without SP had much higher PTSD severity scores. In the entire sample (n=100), the PTSD severity scores correlated significantly with the rate of SP in the last month. During SP, Cambodian refugees usually hallucinated an approaching figure (90%, 44/49). The rate of SP-associated and post-SP panic attacks was high, indicating the great distress caused by the phenomenon. SP seems to be a core aspect of the Cambodian refugee's response to trauma. When treating Cambodian refugees, and traumatized refugees in general, clinicians should assess for its presence.

Behavioral effects of modafinil in marmoset monkeys

RATIONALE

Modafinil is increasingly used in sleep disturbances in general and in neurodegenerative diseases and is recently being used in healthy people for attention control. However, the application of modafinil is possibly not only restricted to alertness enhancing effects. More insight in this compound may lead to new applications. Not all behavioral aspects have been studied sufficiently; therefore, more detailed investigations on modafinil's positive and aversive behavioral effects are addressed in this paper.

OBJECTIVES

Determination of effects of modafinil in marmoset monkeys with observational methods and with behavioral tests measuring locomotor activity, hand-eye coordination, response to a threat situation and startle response.

MATERIALS AND METHODS

Two hours after oral administration of modafinil in doses of 50, 100, 150, and 225 mg/kg, animals were observed and tested in the behavioral test systems.

RESULTS

Locomotor activity was increased after 100 mg/kg modafinil in the Bungalow test and after 100, 150, and 225 mg/kg, as found in the movement parameters of the human threat test. Moreover, modafinil showed anxiolytic-like effects in the human threat test. No other side effects were observed, nor were the hand-eye coordination and startle response affected.

CONCLUSIONS

Besides psychostimulation, modafinil has no aversive effects in the doses used in the domains measured. The potential anxiolytic-like effects of modafinil may create new possibilities for the therapeutic use of modafinil.

Postoperative outcome of patients with narcolepsy. A retrospective analysis

STUDY OBJECTIVE

To determine the postoperative outcome of narcolepsy patients, a population that may be at increased risk of perioperative complications, including postoperative hypersomnia, prolonged emergence after general anesthesia, and apnea.

DESIGN

Retrospective chart review.

SETTING

Academic medical center.

MEASUREMENTS

The perioperative outcome of pharmacologically treated narcolepsy patients, diagnosed at the Mayo Clinic sleep laboratory between January 1, 1965, and December 31, 2001, was studied. A total of 37 narcolepsy patients was identified. Charts were reviewed for the following perioperative (intraoperative time plus recovery room time) events: time for extubation, duration of stay in the Postanesthesia Care Unit (PACU), and duration of stay in the hospital. Furthermore, any of the following complications were noted: electrocardiographic (ECG) changes, postoperative nausea and vomiting, hypotension, subjective reports of pain, decreasing oxygen saturation (SpO(2)) levels, respiratory complications, postoperative fever, agitation in the PACU, and hypersomnolence in PACU. In addition, patient hospital stay and major morbidity and mortality during hospital stay were recorded.

MAIN RESULTS

Ten patients pharmacologically treated for their narcolepsy symptoms that underwent 27 noncardiac surgical procedures under general anesthesia. We found no evidence that the pharmacologically treated narcolepsy patients were at any increased risk for perioperative complications. Furthermore, their time for endotracheal extubation, length of stay in the PACU and hospital did not differ from nonnarcolepsy patients.

CONCLUSION

Pharmacological therapy for narcolepsy should be continued during the perioperative period. In addition, treated narcolepsy patients are at no increased risk for postoperative complications.

Determination of modafinil in plasma and urine by reversed phase high-performance liquid-chromatography

Modafinil (Provigil) is a new wake-promoting drug that is being used for the management of excessive sleepiness in patients with narcolepsy. It has pharmacological properties similar to that of amphetamine, but without some of the side effects associated with amphetamine-like stimulants. Since modafinil has the potential to be abused, accurate drug-screening methods are needed for its analysis. In this study, we developed a high-performance liquid-chromatographic procedure (HPLC) for the quantitative analysis of modafinil in plasma and urine. (Phenylthio)acetic acid was used as an internal standard for the analysis of both plasma and urine. Modafinil was extracted from urine and plasma with ethyl acetate and ethyl acetate-acetic acid (100:1, v/v), respectively, and analyzed on a C18 reverse phase column with methanol-water-acetic acid (500:500:1, v/v) as the mobile phase. Recoveries from urine and plasma were 80.0 and 98.9%, respectively and the limit of quantitation was 0.1 microg/mL at 233 nm. Forty-eight 2-h post-dose urine samples from sham controls and from individuals taking 200 or 400 mg of modafinil were analyzed without knowledge of drug administration. All 16-placebo urine samples and all 32 2-h post-dose urine samples were correctly classified. The analytical procedure is accurate and reproducible and can be used for therapeutic drug monitoring, pharmacokinetic studies, and drug abuse screening.

Current concepts in the etiology, diagnosis and treatment of narcolepsy

Background and purpose: Narcolepsy is the most common neurologic cause of excessive daytime sleepiness. Rapid eye movement (REM) sleep phenomena such as cataplexy, sleep paralysis and hypnagogic hallucinations can also occur. Cataplexy, a sudden bilateral loss of muscle tone usually brought on by emotional reactions such as excitement, is essentially unique to narcolepsy. Narcolepsy, which has a prevalence of 0.02-0.05% in the US, has a profound influence on the quality of life and safety of affected individuals.Patients and methods: The most characteristic and striking physiological abnormality observed in narcolepsy is the sleep-onset REM, or the occurrence of REM sleep at, or within 20 min of, the onset of sleep. The diagnosis is established by nocturnal polysomnography, and the Multiple Sleep Latency Test (MSLT).Results: Familial cases of narcolepsy have been reported, with the risk to first-degree relatives estimated at 1-2%; however, most cases are sporadic and the syndrome is generally believed to involve environmental factors acting on a specific genetic background. The observation of an HLA association in narcolepsy suggests that autoimmunity may play a role in the disorder. However, extensive studies have failed to find convincing evidence of an autoimmune process. Patients with narcolepsy have recently been shown to be deficient in hypocretin, also called orexin, in the cerebrospinal fluid and have a reduction in hypocretin cells in the lateral hypothalamus. This suggests that hypocretins could potentially provide a novel therapeutic approach to the treatment of narcolepsy.Conclusions: Although non-pharmacologic measures can be helpful in treating narcolepsy, most patients require pharmacotherapy that includes psychostimulants or modafinil. Cataplexy is controlled by tricyclic antidepressants or selective serotonin reuptake inhibitors.

Long-term efficacy and safety of modafinil (PROVIGIL((R))) for the treatment of excessive daytime sleepiness associated with narcolepsy

Objectives: To assess the long-term efficacy and safety of modafinil in patients with excessive daytime sleepiness (EDS) associated with narcolepsy.Background: Modafinil has been shown to be effective and well tolerated for treating EDS associated with narcolepsy in two large-scale, well-controlled, 9-week clinical trials.Methods: Four hundred and seventy eight adult patients with a diagnosis of narcolepsy who had completed one of two 9-week, double-blind, placebo-controlled, multicenter, clinical trials of modafinil were enrolled in two 40-week, open-label, extension studies. A flexible-dose regimen (i.e. 200, 300, or 400 mg daily) was followed in one study. In the second study, patients received 200 mg/day for 1 week, followed by 400 mg/day for 1 week. Investigators then prescribed either 200- or 400-mg doses for the duration of the study. Efficacy was evaluated using Clinical Global Impression of Change (CGI-C) scores, the Epworth Sleepiness Scale (ESS), and the 36-item Medical Outcomes Study health survey (SF-36). Adverse events were recorded. Data from the two studies were combined.Results: The majority of patients ( approximately 75%) received 400 mg of modafinil daily. Disease severity improved in >80% of patients throughout the 40-week study. At weeks 2, 8, 24, and 40, disease severity was 'much improved' or 'very much improved' in 49, 58, 59, and 58% of patients, respectively. The mean (+/-SEM) ESS score improved significantly from 16.5+/-0.2 at open-label baseline to 12.4+/-0.2 at week 2 and remained at that level through week 40 (P<0.001). Quality of life scores at weeks 4, 8, 24, and 40 were significantly improved versus open-label baseline scores for six of the eight SF-36 domains (P<0.001). The most common treatment-related adverse events were headache (13%), nervousness (8%), and nausea (5%). Most adverse events were mild to moderate in nature. A total of 341 patients (71%) completed the studies. Forty-three patients (9.0%) discontinued treatment because of adverse events.Conclusions: Modafinil is effective for the long-term treatment of EDS associated with narcolepsy and significantly improves perceptions of general health. Modafinil is well tolerated, with no evidence of tolerance developing during 40 weeks of treatment.