Brand: Compound 347, Ethrane, Forane, Sojourn, Suprane, Terrell, Ultane, Ultane Amerinet, Ultane Novation
Generic: Anesthetic, General (Inhalation Route, Parenteral Route, Rectal Route)
Compound 347, Ethrane, Forane, Sojourn, Suprane, Terrell, Ultane, Ultane Amerinet, Ultane Novation.
General anesthetics (GAs) are the drugs which produce reversible loss of all sensation and consciousness. These agents fall into two types:
(A) Inhalational Anesthetics:
- Nitrous oxide (N2O)
- Ether (Diethyl ether)
- Thiopentone Sodium
- Methohexitone Sodium
- Benzodiazepines (BZDs)
General anesthesia is a reversible, drug-induced state of unresponsiveness to outside stimuli, characterized by non-awareness, analgesia and relaxation of striated muscle. The cardinal features of general anesthesia are given below for better understanding:
- Loss of all sensation, especially pain
- Sleep (unconsciousness) and amnesia
- Immobility and muscle relaxation
- Abolition of somatic and autonomic reflexes.
No single anesthetic drugs can fulfill the criteria mentioned above. Therefore, in modern practice of balanced anesthesia, these modalities are achieved by using combination of inhaled and intravenous drugs, each drug for a specific purpose. A common procedure involves the use of combination of drugs that would be:
- Thiopentone: to produce unconsciousness rapidly (with an intravenous induction agent)
- Nitrous oxide and halothane: to maintain unconsciousness and to produce analgesia (with one or more inhalational agent)
- Tubocurarine: to produce muscle paralysis (with a neuromuscular blocking drugs)
Here, most commonly used general anesthetics are described:
Nitrous oxide (N2O)
It is a general anesthetic agent of low potency. It is non-explosive, non-flammable, slightly sweetish odor gas. It produces light anesthesia without depressing the respiratory centers.
It is a highly potent inhalational anesthetic agent. Surgical anesthesia is produced within 2-5 minutes. Further, it is considered as the best agent for pediatric patient and for patients with bronchial asthma.
Onset of action is very rapid (within 20-30 seconds) due to rapid transfer across blood-brain-barrier; therefore, anesthesia is induced rapidly and pleasantly. This drug is used for induction of anesthesia prior to administration of inhalational and other anesthetics.
Currently, propofol has superseded thiopentone as an intravenous anesthetic, both for induction as well as maintenance. It is an oily liquid employed as 1% emulsion. Unconsciousness after propofol injection occurs in 15-45 seconds and lasts for 5-10 minutes. Intermittent injection or continuous infusion of propofol is frequently used for total intravenous anesthesia when supplemented by fentanyl.
This drug is a highly potent opioid analgesic. It can produce marked analgesia. This medicine is usually used in balanced anesthesia and conscious sedation.
This drug causes loss of consciousness within second. It has no analgesic effect. Rapid recovery occurs following an induction dose (within 3 minutes). Less cardiorespiratory depression has been observed (advantage over other intravenous anesthetic agents).
This unique anesthetic is pharmacologically related to the hallucinogen phencyclidine. It induces a so called “dissociative anesthesia” characterized by profound analgesia, immobility, and amnesia with light sleep.