A Study to Investigate the Drug-drug Interactions Between ACT-541468 and Ethanol in Healthy Subjects

Inclusion Criteria: * Signed informed consent prior to any study-mandated procedure. * Healthy male and female subjects aged between 18 and 45 years (inclusive) at screening. * Women of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test on Day 1 pre-dose of each treatment period. They must consistently and correctly use a reliable method of contraception, be sexually inactive, or have a vasectomized partner. * Women of non-childbearing potential (i.e., postmenopausal). * Body mass index of 18.0 to 32.0 kg/m2 (inclusive) at screening. * Healthy on the basis of medical history, physical examination, cardiovascular assessments and serology and laboratory tests. * Previous experience with alcohol consumption and, therefore, familiar with the effects of alcohol. Exclusion Criteria: * Pregnant or lactating women. * Any circumstances or conditions, which, in the opinion of the investigator, may affect full participation in the study or compliance with the protocol. * Excessive caffeine consumption, defined as ≥ 800 mg per day at screening. * Nicotine intake within 3 months prior to screening and inability to refrain from nicotine intake from screening until End-of-Study (EOS). * Previous treatment with any prescribed medications (including vaccines) or over-the-counter (OTC) medications (including herbal medicines such as St John's Wort, homeopathic preparations, vitamins, and minerals) within 2 weeks prior to first study treatment administration. * History or clinical evidence of alcoholism or drug abuse. * History of regular alcohol consumption within 6 months of the study defined as an average weekly intake of more than 21 units or an average daily intake of more than 3 units (males), or defined as an average weekly intake of more than 14 units or an average daily intake of more than 2 units (females). * Individuals of Asian descent or other individuals reporting ethanol intolerance. * Modified Swiss Narcolepsy Scale total score \< 0 at screening or history of narcolepsy or cataplexy.