Effect of Selective Serotonin Reuptake Inhibitors (SSRIs) and an Opioid on Ventilation

Inclusion Criteria

• Subject signs an Institutional Review Board (IRB) approved written informed consent and privacy language as per national regulations (e.g., Health Insurance Portability and Accountability Act authorization) before any study related procedures are performed.
• Subject is a healthy, non-smoking man or woman, 18 to 50 years of age, inclusive, who has a body mass index of 18.5 to 33.0 kg/m2, inclusive, at Screening.
• Subject has normal medical history findings, clinical laboratory results, vital sign measurements, pulse oximetry, 12-lead ECG results, and physical examination findings at screening or, if abnormal, the abnormality is not considered clinically significant (as determined and documented by the investigator or designee).
• Subject must have a negative test result for alcohol and drugs of abuse at screening and check-in days.
• Subject must test negative for severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) by a rapid antigen test at check-in for all study periods. If a subject's test comes back as invalid, the test can be repeated.
• Female subjects must be of non-childbearing potential (confirmed with follicle-stimulating hormone levels > 40 milli-international unit [mIU]/mL) or, if they are of childbearing potential, they must: 1) have been strictly abstinent for 1 month before check-in (Day -1) and agree to remain strictly abstinent for the duration of the study and for at least 1month after the last application of study drug; OR 2) be practicing 2 highly effective methods of birth control (as determined by the investigator or designee; one of the methods must be a barrier technique) from at least 1 month before check-in (Day -1) until at least 1 month after the end of the study.
• Male subjects must agree to practice 2 highly effective methods of birth control (as determined by the investigator or designee) from at least 1 month before check-in (Day -1) until at least 1 month after the last dose of study drug.
• Subject is highly likely (as determined by the investigator) to comply with the protocol defined procedures and to complete the study.

Exclusion Criteria

• Subject has used any prescription or nonprescription drugs (including aspirin or NSAIDs and excluding oral contraceptives and acetaminophen) within 14 days or 5 half-lives (whichever is longer) or complementary and alternative medicines within 28 days before the first dose of study drug. This includes prescription or nonprescription ophthalmic drugs.
• Subject is currently participating in another clinical study of an investigational drug or has been treated with any investigational drug within 30 days or 5 half-lives (whichever is longer) of the compound.
• Subject has used nicotine-containing products (e.g., cigarettes, cigars, chewing tobacco, snuff, electronic cigarettes) within 6 weeks of Screening. Subjects must refrain from using these throughout the study.
• Subject has consumed alcohol, xanthine containing products (e.g., tea, coffee, cola), caffeine, grapefruit, or grapefruit juice within 24 h of check-in. Subjects must refrain from ingesting these throughout the study.
• Subject has a history or evidence of a clinically significant disorder, condition, or disease (e.g., cancer, human immunodeficiency virus [HIV], hepatic or renal impairment) that, in the opinion of the investigator would pose a risk to subject safety or interfere with the study evaluation, procedures, or completion. This includes subjects with any underlying medical conditions that put subjects at increased risk of severe illness from coronavirus disease 2019 (COVID-19) based on the Centers for Disease Control and Prevention (CDC) guidelines.
• Subject has any signs or symptoms at screening or check-in of any study periods that are consistent with COVID-19. Per current CDC recommendations this includes subjects with the symptoms cough or shortness of breath or difficulty breathing, or at least two of the following symptoms: f