To Tranquilize

1. (transitive) To calm (a person or animal) or put them to sleep using a drug.
2. The escaped lion was finally tracked down, tranquilized, and safely returned to the zoo.

Synonym: sedate

3. (transitive, now literary) To make (something or someone) tranquil.

Synonyms: appease, calm, pacify

4. (intransitive, obsolete, rare) To become tranquil.

Synonyms: calm down, relax

madden