An antidepressant, in the most common usage, is a medication taken to alleviate clinical depression or dysthymia ('milder' depression). Several groups of drugs are particularly associated with the term, notably MAOIs and tricyclics (whose serendipitous discovery and psychiatric use dates from the 1950s) as well as SSRIs and more recent variations developed by pharmaceutical companies. These medications are now amongst the most commonly prescribed by psychiatrists and general practitioners, and their effectiveness and adverse effects are the subject of many studies and competing claims. A number of other antidepressant drugs, notably St John's Wort, are also widely studied and used.

Antidepressants are generally, if not in pharmacology, considered separately from stimulants. They are usually taken as a course over several weeks, months or years, and have a delayed onset of therapeutic action. Drugs used for an immediate euphoric effect only are not generally considered antidepressants. Despite the name, antidepressants are often used in the treatment of other conditions, including anxiety disorders, bipolar disorder, eating disorders and chronic pain. Some have also become known as lifestyle drugs, sometimes referred to as "mood brighteners". Conversely other medications not known as antidepressants, including antipsychotics in low doses and benzodiazepines are also widely used to manage depression. In fact the antidepressant term is sometimes applied to any therapy (e.g. psychotherapy, electro-convulsive therapy, acupuncture) or process (e.g. sleep disruption, increased light levels, regular exercise) found to improve clinically depressed mood. It is also the case that placebos tend to have a significant antidepressant effect, so that establishing a drug as an antidepressant in a clinical trial involves demonstrating a significant additional effect.

Elavil is a tricyclic antidepressant drug. It is a white, odorless, crystalline compound which is freely soluble in water and usually dispensed in tablet form.

Elavil is approved for the treatment of endogenous depression and involutional melancholia (depression of late life, which is no longer seen as a disease in its own right), and reactive depression and for depression secondary to alcoholism and schizophrenia. Adult typical dosages are 75 to 200 mg daily, with half this initially for elderly or adolescents. It may also be used to treat nocturnal enuresis (bed wetting). Children between the ages of 7 to 10 years having a dose of 10 to 20 mg, older children 25 to 50 mg at night. It should be gradually withdrawn at the end of the course, which overall should be of no more than 3 months.[3]

Prozac or Fluoxetine hydrochloride is an antidepressant drug used medically in the treatment of depression, body dysmorphic disorder, obsessive-compulsive disorder, bulimia nervosa, premenstrual dysphoric disorder, hypochondriasis and panic disorder. Fluoxetine was derived from an antihistamine found to inhibit reuptake of the neurotransmitter serotonin.

Approved
Fluoxetine hydrochloride is approved in the United States to treat depression, obsessive-compulsive disorder, bulimia nervosa, premenstrual dysphoric disorder and panic disorder. In the United Kingdom, it is approved to treat depression with or without anxiety, bulimia nervosa, and obsessive-compulsive disorder.