A Study to Investigate the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of TAK-954 in Healthy Adult Participants

A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single Ascending Dose, 3-Period, Incomplete Block Design Study to Investigate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of TAK-954 in Healthy Adult Participants

The purpose of this study is to evaluate the safety, tolerability, and PK of single ascending intravenous doses of TAK-954.

The drug being tested in this study is called TAK-954. This study will assess the safety, tolerability, PK and PD of single ascending TAK-954 higher intravenous doses than those previously studied.

The study will enroll approximately 6 participants. Participants will be randomly assigned (By chance, like flipping a coin) to one of the three treatment sequences-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need).

In each treatment sequence, each participant will receive 2 doses of active drug out of 3 dose levels (TAK-954 0.5 mg, TAK-954 1 mg, or TAK-954 2 mg) and 1 dose of Placebo. Dose escalation will be based on the available safety/tolerability data from the previous period.

This single center trial will be conducted in the United States. The overall time to participate in this study is approximately 73 days. Participants will make a final visit on Day 16 after receiving their last dose of study drug for a follow-up assessment.

Inclusion Criteria:

1. Body mass index (BMI) greater than or equal to (>=) 18 and less than or equal to (<=) 32 kilogram per square meter (kg/m^2), weighing >=50 kilogram (kg) at screening.
2. Medically healthy with no clinically significant medical history, physical examination, laboratory profiles, vital signs, orthostatic vital signs, or ECGs, as deemed by the Investigator or designee.
3. Continuous non-smoker who has not used nicotine-containing products for at least 3 months prior to the first dose and throughout the study, based on participant self-reporting.

Exclusion Criteria:

1. History or presence of alcoholism or drug abuse within the past 2 years prior to the first dosing.
2. Has infrequent bowel movements (less than approximately once per day) within 30 days prior to first dosing.
3. Recent history of abnormal bowel movements, such as diarrhea, loose stools, or constipation, within 2 weeks of first dosing.