Anesthetics have side effects on the body because they are drugs that target the nervous system and may also remain in the brain cells for a longer period of time after they have had an anesthetic or sleep effect. Side effects of anesthetics include drowsiness, confusion, mood swings, and abnormal thinking, and may cause allergic reactions and other side effects. All medications have side effects, but the side effects of qualifying medications usually go away relatively quickly, and because of the metabolic cycle of the medication, they do not have a lifelong effect on the patient after application. Most anesthesia drugs only affect the body for a short period of time. After the half-life of the drug, the effects are eliminated and the patient can live a normal life. Unless a serious anesthetic accident occurs, the patient’s life may be in danger.