MSI_000057450

Doxepin hydrochloride is a dibenzoxepin-derivative tricyclic antidepressant (TCA). TCAs are structurally similar to phenothiazines. They contain a tricyclic ring system with an alkyl amine substituent on the central ring. In non-depressed individuals, doxepin does not affect mood or arousal, but may cause sedation. In depressed individuals, doxepin exerts a positive effect on mood. TCAs are potent inhibitors of serotonin and norepinephrine reuptake. Tertiary amine TCAs, such as doxepin and amitriptyline, are more potent inhibitors of serotonin reuptake than secondary amine TCAs, such as nortriptyline and desipramine. TCAs also down-regulate cerebral cortical β-adrenergic receptors and sensitize post-synaptic serotonergic receptors with chronic use. The antidepressant effects of TCAs are thought to be due to an overall increase in serotonergic neurotransmission. TCAs also block histamine H₁ receptors, α₁-adrenergic receptors and muscarinic receptors, which accounts for their sedative, hypotensive and anticholinergic effects (e.g. blurred vision, dry mouth, constipation, urinary retention), respectively. Doxepin has less sedative and anticholinergic effects than amitriptyline. See toxicity section below for a complete listing of side effects. Doxepin may be used to treat depression and insomnia. Unlabeled indications include chronic and neuropathic pain, and anxiety. Doxepin may also be used as a second line agent to treat idiopathic urticaria. D - Dermatologicals > D04 - Antipruritics, incl. antihistamines, anesthetics, etc. > D04A - Antipruritics, incl. antihistamines, anesthetics, etc. N - Nervous system > N06 - Psychoanaleptics > N06A - Antidepressants > N06AA - Non-selective monoamine reuptake inhibitors D002491 - Central Nervous System Agents > D002492 - Central Nervous System Depressants > D006993 - Hypnotics and Sedatives C78272 - Agent Affecting Nervous System > C265 - Antidepressant Agent > C94727 - Tricyclic Antidepressant D002491 - Central Nervous System Agents > D011619 - Psychotropic Drugs > D000928 - Antidepressive Agents D018377 - Neurotransmitter Agents > D018494 - Histamine Agents > D006633 - Histamine Antagonists EAWAG_UCHEM_ID 3676; CONFIDENCE standard compound CONFIDENCE standard compound; EAWAG_UCHEM_ID 3676