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Description

Doxepin is a dibenzoxepin tricyclic antidepressant marketed worldwide. It is a white crystalline solid readily soluble in water, lower alcohols and chloroform. The mechanism of action of doxepin is not definitely known. It is not a central nervous system stimulant nor a monoamine oxidase inhibitor. The current hypothesis is that the clinical effects are due, at least in part, to influences on the adrenergic activity at the synapses so that deactivation of norepinephrine by reuptake into the nerve terminals is prevented. Antidepressants may increase risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (18–24 years of age) with major depressive disorder and other psychiatric disorders. Drowsiness is the most commonly noticed side effect. This tends to disappear as therapy is continued. Other infrequently reported CNS side effects are confusion, disorientation, hallucinations, numbness, paresthesias, ataxia, extrapyramidal symptoms, seizures, tardive dyskinesia, and tremor. : Cardiovascular effects including hypotension, hypertension, and tachycardia have been reported occasionally. Skin rash, edema, photosensitization, and pruritus have occasionally occurred. Eosinophilia has been reported in a few patients. There have been occasional reports of bone marrow depression manifesting as agranulocytosis, leukopenia, thrombocytopenia, and purpura. Doxepin is used to treat depression, anxiety disorders, itchiness, trouble sleeping, and as a second-line treatment of chronic idiopathic urticaria (hives). Its oral formulations are FDA-approved for the treatment of depression, anxiety, and insomnia and its topical formulations are FDA-approved the short-term management (up to 8 days) of atopic dermatitis and lichen simplex chronicus. Whereas in Australia and the UK, the only licensed indication(s) is/are in the treatment of major depression and pruritus in eczema, respectively.

CNS Activity

Originator

Approval Year

Targets

Primary TargetPharmacologyConditionPotency

Conditions

ConditionModalityTargetsHighest PhaseProduct
Primary
SINEQUAN
Primary
SINEQUAN
Primary
ZONALON

PubMed

Patents

Sample Use Guides

In Vivo Use Guide
For Mild Anxiety: Initial dose: 25 mg per day in 1 to 3 divided doses. Maintenance dose: 25 to 50 mg per day in 1 to 3 divided doses. For Moderate Anxiety: Initial dose: 75 mg per day in 1 to 3 divided doses. Maintenance dose: 75 to 150 mg per day in 1 to 3 divided doses. For Severe Anxiety: Initial dose: 150 mg per day in 1 to 3 divided doses. Maintenance dose: 150 to 300 mg per day in 1 to 3 divided doses. The maximum single dose should not exceed 150 mg. For treatment moderate pruritus A thin film of Doxepin should be applied four times each day with at least a 3 to 4 hour interval between applications. There are no data to establish the safety and effectiveness of Doxepin when used for greater than 8 days. Chronic use beyond eight days may result in higher systemic levels and should be avoided.
Route of Administration: Other
In Vitro Use Guide
Doxepin effects were studied on rat vas deferens responses to noradrenaline. Tissues were prepared in Krebs-Henseleit solution. In normal Krebs-Henseleit solution doxepin behaved as competitive antagonists.
Substance Class Mixture
Record UNII
5ASJ6HUZ7D
Record Status Validated (UNII)
Record Version
All of the following components must be present:
Definition References
(3)