General anaesthesia drug infusion. Anaesthesiologist administering propofol for the induction of general anaesthesia. General anaesthesia is where a patient is rendered unconscious to allow major surgery to be performed. A variety of drugs and anaesthetic agents are used. Propofol is a hypnotic drug that induces unconsciousness. It is injected intravenously and commonly used with a painkilling drug (analgesic) such as fentanyl (see image C029/9025).