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 H<sub>1</sub> receptors, α<sub>1</sub>-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.
Alti-doxepin - Cap 10mg
Humans and other mammals
Doxepin is used for the treatment of depression and/or anxiety. It can also be used for chronic urticaria and in the management of pain.
Doxepin, a tricyclic antidepressant of the dibenzoxepin type, is used to treat depression and anxiety and, topically, pruritus associated with eczema. Doxepin has substantial anticholinergic and sedative effects. The E (trans)-isomer is more active as a serotonin reuptake inhibitor while the Z-isomer acts as a sedative.
Mechanism of action
The mechanism of action of doxepin is not completely understood. It is thought that like amitriptyline, doxepin enhances the actions of norepinephrine and serotonin by blocking their reuptake at the neuronal membrane. However, doxepin weakly inhibits the reuptake of dopamine. Doxepin may also act on histamine H<sub>1</sub>-receptors, resulting in sedative effects, and β-adrenergic receptors. It is also an antagonist of 5-hydroxytryptamine (serotonin) receptors, alpha-1 adrenergic receptor, and muscarinic cholinergic receptors.
Route of administration
Antidepressive Agents, Tricyclic
Central Nervous System Agents
Central Nervous System Depressants
Chemical Actions and Uses
Cytochrome P-450 CYP1A2 Substrates
Cytochrome P-450 CYP2C19 Substrates
Cytochrome P-450 CYP2C9 Substrates
Cytochrome P-450 CYP2D6 Inhibitors
Cytochrome P-450 CYP2D6 Substrates
Cytochrome P-450 CYP3A4 Substrates
Heterocyclic Compounds, 1-Ring
Heterocyclic Compounds, 3-Ring
Molecular Mechanisms of Pharmacological Action
Non-Selective Monoamine Reuptake Inhibitors
Physiological Effects of Drugs
QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying)
Drug Info/Drug Targets: DrugBank 3.0: a comprehensive resource for 'omics' research on drugs. Knox C, Law V, Jewison
T, Liu P, Ly S, Frolkis A, Pon A, Banco K, Mak C, Neveu V, Djoumbou Y, Eisner R, Guo AC, Wishart DS.
Nucleic Acids Res. 2011 Jan; 39 (Database issue):D1035-41. | PMID:21059682