Sleep inducing drugs are substances that can be used to help people fall asleep or stay asleep. Codeine is a narcotic analgesic drug derived from the opium poppy plant and is commonly used as a cough suppressant. OPIATE is a term used to describe any drug derived from the opium poppy plant, including codeine. SEDATIVE is a type of drug that is used to reduce anxiety, induce sleep, or reduce pain. All three of these drugs are commonly used as sleep inducing drugs.