A hypno-sedative was a class of drugs and treatments, a type of anesthesia used by Federation science in the 23rd century.
History and specifics[]
A hypno-sedative was administered to lightly sedate a patient so that they were more susceptible to hypnosis.
In 2274, Doctor Christine Chapel considered the possibility that the Imperator of Zeta-Atez Dykranus was being given hypno-sedatives that compelled him to take frequent naps. Leonard McCoy agreed that the symptoms fit. Both were unaware that he hid the true cause of his symptoms, genetic bicephaly. (TOS comic: "Heads of State")