After intravenous anesthesia, patients typically fall asleep in 30 seconds to 1 minute. The speed at which the patient falls asleep depends on the type of general anesthetic and the speed at which the anesthetic solution is pushed in. The most commonly used general anesthetic drug is propofol, which is pushed in for 30 seconds to 1 minute after the patient falls asleep. Another commonly used intravenous anesthetic drug is etomidate, which is comparable to propofol in speed. If other drugs are given, such as slow-acting imipramine and sodium gamma-hydroxybutyrate, the patient does not fall asleep as quickly. If a combination of multiple anesthetic drugs is present, the onset of action may be even faster.