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.
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.
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.
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.
*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.