Sedative and Hypnotics...
It's a substance that induces sedation by reducing irritability or excitement.
Doses of sedatives such as benzodiazepines when used as a hypnotic to induce sleep tend to be higher than those used to relieve anxiety whereas only low doses are needed to provide calming sedative effects.

Sedatives can be abused to produce an overly-calming effect. At high doses or when they are abused, many of these drugs can cause unconsciousness and even death.

Pentobarbitone... a short-acting barbiturate that was first synthesized in 1928. available as both a free acid and a sodium salt, the former of which is only slightly soluble in water and ethanol.

Glutethimide.. a hypnotic sedative that was introduced in 1954 as a safe alternative to barbiturates to treat insomnia. Before long, however, it had become clear that glutethimide was just as likely to cause addiction and caused similarly severe withdrawal symptoms. Doriden is the brand-name version of the drug; both the generic and brand-name forms are rarely prescribed today.

In long term use rebound effects, which resembled those seen in withdrawal, have anecdotally been described in patients, who were still taking a stable dose of the drug. The symptoms included delirium, hallucinosis, convulsions and fever.

Methaqualone... a sedative-hypnotic drug that is similar in effect to barbiturates, a general central nervous system depressant. was first synthesized in India in 1951 by Indra Kis Kacker and Syed Hussain Zaheer.

effect.. can include euphoria, drowsiness, reduced heart rate, reduced respiration, increased s*xual arousal (aphrodisia), and paresthesias (numbness of the fingers and toes). Larger doses can bring about respiratory depression, slurred speech, headache, and photophobia (a symptom of excessive sensitivity to light).

popular as a recreational drug..