Nortriptyline is a second-generation tricyclic antidepressant (TCA). It is used in the treatment of major depression and childhood nocturnal enuresis. In addition, it is sometimes used for chronic illnesses such as chronic fatigue syndrome, chronic pain and migraine, and labile affect in some neurological conditions. Nortriptyline is metabolized in the liver by the hepatic enzyme CYP2D6. Nortriptyline is an active metabolite of amitriptyline that is demethylated in the liver. Blood levels of nortriptyline should be obtained during long term treatment to avoid toxicity and optimize response. Nortriptyline should not be used in the acute recovery phase after myocardial infarction. As for all tricyclic antidepressants, concurrent use, or failure to allow a two-week gap with monoamine oxidase inhibitors may precipitate hyperpyretic crisis caused by serotonin syndrome or severe convulsions.