Doxepin

Doxepin is a psychotropic agent with antidepressant and anxiolytic properties. It is a tertiary amine that can be presented as (E) and (Z) stereoisomers with the (Z) stereoisomer corresponding to cidoxepin. Doxepin commonly produces a 5:1 (E):(Z) racemic mixture.

In a strict sense, doxepin is not a tricyclic antidepressant but it is commonly associated with the class since it shares a lot of properties with members of the drug family including amitriptyline, clomipramine, desipramine, imipramine, nortriptyline, protriptyline and trimipramine.

Doxepin was developed by Pfizer and FDA approved in 1969 as an antidepressant. However, in 2010 it was approved for the treatment of insomnia. The latter indication was presented by Pernix Therapeutics.

Oral doxepin is approved for the following indications:

Topical doxepin is also approved for short-term (up to 8 days) management of moderate pruritus in adult patients with atopic dermatitis, pruritus or lichen simplex chronicus.

Off-label, doxepin is used topically for the management of neuropathic pain.

Depression is a common medical illness that causes feelings of sadness and or loss of interest in prior enjoyable activities. This condition can lead to emotional and physical disturbances that can decrease the ability of a person to function in a regular environment.

Anxiety is a normal reaction of the body towards a normal danger. When the anxious state is exacerbated or appears on situations without danger, it is defined as an anxiety disorder. This disorders can appear in different forms such as phobias, panic, obsessive-compulsive disorder and post-traumatic stress disorder.

Insomnia is a sleep disorder that directly affects the quality of life of the individual. It is characterized by the complication either to fall asleep or to stay asleep. This condition can be occasional or chronic.

Pruritus is defined as an unpleasant skin reaction that provokes the urge to scratch. It can be localized or generalized and it can appear in an acute or chronic manner.

Neuropathic pain occurs due to the damage or dysfunction of the peripheral or central nervous system rather than stimulation of the pain receptors.