A Study to Evaluate the Effect of the Potent Cytochrome P-450 3A4 (CYP3A4) Inhibitor Itraconazole on the Pharmacokinetics (PK) of TAK-954 in Healthy Adult Participants

The drug being tested in this study is called TAK-954. TAK-954 is being tested in healthy participants in order to evaluate the effect of the potent CYP3A4 inhibitor itraconazole on the single-dose PK of TAK-954.

The study will enroll approximately 10 participants. Participants will receive the following treatment sequences:

• TAK-954 0.2 mg; Itraconazole 200 mg + TAK-954 0.2 mg

Participants will be given an intravenous infusion of TAK-954 on Day 1 of First Intervention Period (6 days) followed by minimum 7-day washout period, after which participants will be given Itraconazole capsule on Days 1 to 8 along with TAK-945 infusion on Day 4 of Second Intervention Period (9 days).

This single center trial will be conducted in the United States. The overall duration to participate in this study is 7 to 8 weeks. Participants will visit the clinic on Day -1 and remained confined until Day 6 (First Intervention Period) and Day 9 (Second Intervention Period). Participants will return for a Follow-up Visit 10 to 14 days after last dose of study drug (approximately up to Day 34).

Inclusion criteria

• Is a man or woman (with no child bearing potential) aged 18 to 55 years, inclusive, at the Screening Visit.
• Has a body mass index (BMI) from greater than or equal to (>=) 18 and less than or equal to (<=) 30 kilogram per square meter (kg/m^2) and has a body weight greater than (>) 50 kilogram (kg) at the Screening Visit.
• Is a nonsmoker who has not used tobacco- or nicotine-containing products (example, nicotine patch) for at least 6 months before administration of the initial dose of trial drug/invasive procedure.

Exclusion criteria

• Has a positive alcohol or drug screen.
• Had major surgery, donated or lost 1 unit of blood (approximately 500 milliliter (mL)) within 8 weeks of the first dose of study drug.
• Has a history of alcohol consumption exceeding 2 standard drinks per day on average (1 glass is approximately equivalent to: beer [354 mL/12 ounces], wine [118 mL/4 ounces], or distilled spirits [29.5 mL/1 ounce] per day).
• Consumes excessive amounts, defined as greater than 6 servings (1 serving is approximately equivalent to 120 mg of caffeine) of coffee, tea, cola, energy drinks, or other caffeinated beverages per day.
• Has a substance abuse disorder.