Sleeping gas

Sleeping gas is a fictional oneirogenic gas described in books and films. In these works of fiction, sleeping gas induces a deep delta sleep. Most of the time, it is used by a character to incapacitate another character or characters. In some cases, science fiction or fantasy films depict the use of large quantities of sleeping gas to put large numbers of people to sleep.

Sleeping gases, as opposed to laughing gases, are inhalational general anaesthetics that put the patient, or victim, into a state where they are not conscious of what is happening around them. Incapacitating agent is a related general term for “knockout gasses” or “KO gases” that ideally render a person unable to harm themselves or others, regardless of consciousness.

Most real world sleeping gases have undesirable side effects, or are effective at doses that approach toxicity.

Examples of modern volatile anaesthetics that may be considered sleeping gases are halothane vapour (Fluothane), methyl propyl ether (Neothyl), methoxyflurane (Penthrane), and the undisclosed fentanyl derivative delivery system used by the KGB in the Moscow theater hostage crisis.

Possible side effects might not prevent use of sleeping gas by criminals willing to murder, or carefully control the dose on a single already sleepy individual. There are urban legends of thieves spraying sleeping gases on campers, or in train compartments in some parts of Europe. Alarms are sold to detect and alert to such attacks, so a potential risk is believed by some people.

Fictional use of sleeping gas often involves stealth, as does criminal use of sleeping pills and poisons. The volatile anaesthetics noted above have odors. Odorless gas, eg. methane (CH₄), carbon dioxide (CO₂) and carbon monoxide (CO), is a serious public health concern because people/animals may not be alerted to escape. Suffocation is a concern even for non-toxic gases. To prevent in-home death, many countries require gaslines to have odorants added to the gas.