Original ArticlesModafinil Reduces Parasympathetic Activity but Does Not Influence Autonomic Reactivity to Orthostatic Load in Narcolepsy Type 1Bušek, Petr MD, PhD*†; Bušková, Jitka MD, PhD‡§; Miletínová, Eva MD, MSc‡; Mladá, Karolína Mgr‡; Nevšímalová, Soňa DSc*†; Šonka, Karel DSc*†Author Information *Department of Neurology, Center of Clinical Neuroscience, First Faculty of Medicine, Charles University in Prague; †General University Hospital in Prague; ‡National Institute of Mental Health, Klecany; and §Third Faculty of Medicine, Charles University in Prague, Czech Republic. Address correspondence and reprint requests to Jitka Bušková, MD, PhD, National Institute of Mental Health, Klecany, 250 67, Czech Republic; E-mail: firstname.lastname@example.org Conflicts of Interest and Source of Funding: This study was supported by the project number LO1611 with financial support from the MEYS under the NPU I program, by PROGRES Q35 and by the Czech Science Foundation, grant number 16-07879S. The authors have no conflicts of interest to declare. Clinical Neuropharmacology: 7/8 2018 - Volume 41 - Issue 4 - p 111-115 doi: 10.1097/WNF.0000000000000287 Buy Metrics Abstract Introduction Modafinil may affect autonomic functions in healthy subjects. The aim of the study was to assess the long-term modafinil administration influence on the cardiac autonomic reactivity to orthostatic load in patients with narcolepsy type 1. Methods In 15 patients (4 male; 11 female; median age, 47 years; range, 18–70 years) with narcolepsy type 1 treated with modafinil in daily dose of 100 to 300 mg, the short-term spectral analysis of heart rate variability (HRV) in supine-standing-supine test was performed before and after 72 hours of modafinil discontinuation. Results The sympathovagal reactivity to orthostatic load was not modified by modafinil treatment; nevertheless, the parasympathetic activity expressed by length of R-R interval and high-frequency component of HRV is reduced in supine position in patients taking modafinil. Conclusions We conclude that long-term use of modafinil does not influence the cardiac autonomic reactivity to orthostatic load expressed by the HRV changes in supine-standing-supine test in narcolepsy type 1 patients, but the parasympathetic cardiac activity may be reduced in quiet supine position in patients with narcolepsy taking modafinil. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.