ATC Code N06AX05
Formula C19H22ClN5O
Molar Mass (g·mol−1) 371,86
Physical State solid
Melting Point (°C) 87
PKS Value 6,14
CAS Number 19794-93-5
PUB Number 5533
Drugbank ID DB00656
Solubility soluble in water


Trazodone is a triazolopyridine derivative of the serotonin receptor antagonist and reuptake inhibitor class of antidepressants. It is used in adults and has been shown to be effective in treating depression alongside other medications such as tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), and serotonin-norepinephrine receptor inhibitors (SNRIs). A unique feature of this drug is that it does not promote side effects such as anxiety, sexual dysfunction, or insomnia that are commonly associated with SSRI and SNRI therapy. It is used to treat major depressive disorder, anxiety disorders, and alcohol dependence. It is taken perorally, usually in the form of tablets.



The mechanism of action of trazodone is not fully understood, but it is known to inhibit serotonin reuptake and block both histamine and alpha 1-adrenoreceptors. Although trazodone is often considered a selective inhibitor of serotonin reuptake, several reports have shown that other mechanisms, including antagonism at additional serotonin receptor subtypes, may occur. The antidepressant effect of trazodone results from inhibition of the "reuptake" of serotonin from the synaptic cleft back into the presynapse. This permanently increases the concentration of serotonin and counteracts the depressive disorder.


Trazodone is rapidly absorbed in the gastrointestinal tract after oral administration, with bioavailability ranging from 63-91%. Plasma protein binding of trazodone is 89-95% according to in vitro studies. Trazodone is highly metabolized and activated in the liver by the enzyme CYP3A4. Approximately 60-70% of the dose is excreted in the urine within 48 hours of administration. Approximately 9-29% over a period of 60 to 100 hours is excreted in the feces.


Trazodone is metabolized by several liver enzymes, including CYP3A4, CYP2D6, and CYP1A2. In general, any drug that is metabolized by or induces the same enzymes should not be combined with trazodone.

Severe and possibly fatal side effects (e.g.: serotonin syndrome) can be triggered by drugs that have a similar effect on serotonin action in the CNS. Therefore, combination with other antidepressants, especially MAO inhibitors, should be avoided.


Side effects

Side effects can be extensive due to the interference with the brain's serotonin system.

The most common side effects are:

  • Blurred vision
  • Dizziness
  • Somnolence
  • Dry mouth
  • Nausea
  • Headache
  • Fatigue

Toxicological data

LD50 (rat, oral): 690 mg/kg.

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All information used for the content comes from verified sources (recognised institutions, experts, studies by renowned universities). We attach great importance to the qualification of the authors and the scientific background of the information. Thus, we ensure that our research is based on scientific findings.

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter is a writer on pharmaceutical topics in Medikamio's medical editorial team. He is in the last semester of his pharmacy studies at the University of Vienna and loves scientific work in the field of natural sciences.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer has been a freelance writer for Medikamio since 2020 and studied pharmacy at the University of Vienna. She works as a pharmacist in Vienna and her passion is herbal medicines and their effects.

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