This study will be conducted to evaluate the effect of lemborexant 10 milligrams (mg) (at steady state) on the pharmacokinetics (PK) of a single-dose combined oral contraceptive, Loestrin 1.5/30 (containing 0.030 mg of ethinyl estradiol and 1.5 mg of norethindrone), and to evaluate the effect of fluconazole 200 mg (at steady state) and a single dose of famotidine 40 mg (an H2 blocker) on the PK of a single oral dose of lemborexant 10 mg.

Inclusion Criteria:

Inclusion Criteria for All Participants (Part 1 - Oral Contraceptive; Part 2 - Famotidine; Part 3 - Fluconazole)

Participants who meet all of the following inclusion criteria will be eligible for participation in the study:

• Body mass index >18 and ≤32 kilograms per meters squared at Screening
• Are willing and able to comply with all aspects of the protocol
• Provide written informed consent

Additional Inclusion Criteria for Part 1 - Oral Contraceptive

• Healthy female participants, ages 18 to 44 years old (inclusive) at Screening
• Must not be taking any form of hormonal contraceptives, including hormonal intra-uterine device, for at least 8 weeks prior to dosing

Additional Inclusion Criteria (Part 2 - Famotidine; Part 3 - Fluconazole)

-Healthy male or female, age ≥18 years and ≤55 years old at the time of informed consent

Exclusion Criteria:

• Known contraindication to Loestrin (only for Part 1), to Famotidine (only for Part 2), or to Fluconazole (only for Part 3)
• Females who are breastfeeding or pregnant at Screening or Baseline.
• Females of childbearing potential. NOTE: All females will be considered to be of childbearing potential unless they are postmenopausal (amenorrheic for at least 12 consecutive months, in the appropriate age group, and without other known or suspected cause) or have been sterilized surgically (i.e., bilateral tubal ligation, total hysterectomy, or bilateral oophorectomy, all with surgery at least 1 month before dosing).
• Clinically significant illness that requires medical treatment within 8 weeks or a clinically significant infection that requires medical treatment within 4 weeks of dosing
• Presence of significant illness that requires treatment or may influence the study assessments (e.g. psychiatric disorders, disorders of the gastrointestinal tract, liver, kidney, respiratory system, endocrine system, hematological system, neurological system, cardiovascular system, or a congenital abnormality)
• Any history of abdominal surgery that may affect PK profiles of lemborexant (eg, hepatectomy, nephrectomy, digestive organ resection) at Screening
• Any other clinically abnormal symptom or organ impairment found by medical history, physical examinations, vital signs, electrocardiogram (ECG) finding, or laboratory test results that requires medical treatment at Screening or Baseline
• A prolonged QT/corrected QT (QTc) interval (QTc >450 milliseconds) demonstrated on ECG at Screening or Baseline
• Persistent systolic blood pressure (BP) >160 millimeters of mercury (mmHg) or diastolic BP >100 mmHg at Screening or Baseline (based on BP measured on at least 3 occasions over 2 weeks)
• Persistent heart rate (HR) of <50 beats per minute (beats/min) or >90 beats/min at Screening or Baseline (based on HR measured on at least 3 occasions over 2 weeks)
• Known history of clinically significant drug allergy at Screening or Baseline
• Known history of food allergies or presently experiencing significant seasonal or perennial allergy at Screening or Baseline
• Known to be human immunodeficiency virus positive
• Active viral hepatitis (B or C) as demonstrated by positive serology at Screening
• History of drug or alcohol dependency or abuse within the 2 years before Screening
• Participants who smoke or have used tobacco or nicotine-containing products within 4 weeks before dosing
• Any suicidal ideation with intent with or without a plan at Screening or within 6 months of Screening (ie, for Part 1 answering "Yes" to questions 4 or 5 on the Suicidal Ideation section of the Columbia-Suicide Severity Rating Scale) or any suicidal behavior in the past 10 years.
• Currently enrolled in another clinical trial or used any investigational drug or device within 30 days (or 5 half-lives, whichever is longer) preceding informed consent
• Engagement in strenuous exercise within 2 weeks before check-in (e.g., marathon runners, weight lifters)
• Intake of caffeinated beverages or caffeinated food within 72 hours before dosing and during the course of the study
• Intake of food supplements (including herbal preparations), foods, or beverages that may affect cytochrome P4503A4 enzyme (e.g., alcohol, grapefruit, grapefruit juice, grapefruit-containing beverages, apple or orange juice, vegetables from the mustard green family [e.g., kale, broccoli, watercress, collard greens, kohlrabi, Brussels sprouts, mustard], and charbroiled meats) within 1 week before dosing
• Intake of herbal preparations containing St. John's Wort within 4 weeks before dosing
• Intake of prescription or over-the-counter medications within 14 days (or 5 half-lives, whichever is longer) before dosing unless the Principal Investigator and medical monitor consider that they do not compromise participant safety or study assessments
• A positive urine drug test, a positive breathalyzer alcohol test, or, if appropriate, a positive serum pregnancy test