Anesthetic drugs are unique in that they are seldom used outside of the operating room setting. For induction of general anesthesia, the intravenous agent propofol is commonly used. It is shorter acting and associated with less nausea and vomiting compared with the many other choices. The general anesthetic state is maintained with a mixture of gases and intravenous agents. The trade names of the gases are forane, suprane and sevoflurane. They are administered from machines called vaporizers. Other classes of drugs are also used. Narcotics are given as an adjuvant to the inhaled gases. The common ones used include morphine, dilaudid, fentanyl and sufentanyl. To facilitate the placement of the breathing tube after anesthetic induction, a muscle relaxant is given. There are many brand names and common ones used include succinylcholine, rocuronium and vecuronium. The use of succinylcholine can result in muscle pains postoperatively (myalgias).