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Nefazodone chemical structure

IUPAC name
CAS number
ATC code


Chemical formula {{{chemical_formula}}}
Molecular weight 506.5 g/mol
Bioavailability 20% (IV only)
Metabolism Hepatic (active metabolites)
Elimination half-life 2–4 hours
Excretion 55% urine
20-30% feces
Pregnancy category {{{pregnancy_category}}}
Legal status Rx-only
Routes of administration oral

Nefazodone hydrochloride (trade name Serzone) is an antidepressant drug marketed by Bristol-Myers Squibb. Its sale was discontinued in 2003 in some countries, due to the small possibility of hepatic (liver) injury, which could lead to the need for a liver transplant, or even death. The incidence of severe liver damage is approximately 1 in 250,000 to 300,000 patient-years.[1] On May 20, 2004, Bristol-Myers Squibb discontinued the sale of Serzone in the United States. Several generic formulations of nefazodone are still available.[2][3]

Structure and mode of action

Nefazodone is most closely related to trazodone (trade name Desyrel). Nefazodone is not considered to be an SSRI, MAOI or tricyclic antidepressant. It is not chemically related to either bupropion/amfebutamone or venlafaxine.

It operates by blocking post-synaptic serotonin type-2A receptors and, to a lesser extent, by inhibiting pre-synaptic serotonin and norepinephrine (noradrenaline) reuptake. Nefazodone is also a relatively potent alpha-1 adrenoceptor antagonist.[4]


Nefazodone doses for adults typically start at 50 mg twice daily uptitrated by 100 mg/day per week to a maximum of 600 mg (300 mg twice daily), according to Food and Drug Administration (FDA) regulations. Some patients with severe depression were treated with more than 600 mg/day. Most patients were treated with 300 mg–600 mg daily.

Side effects

Nefazodone and other SNRIs and SSRIs have been shown to cause sexual side effects in some patients, both males and females. Although usually reversible, these sexual side effects can sometimes last for months, years or possibly indefinitely even after the drug has been completely withdrawn. This disorder is known as Post SSRI Sexual Dysfunction. However, nefazodone is associated with a very low incidence of sexual side effects. Indeed, nefazodone is sometimes used as an antidote to SSRI induced impotence and anorgasmia in men.[5]


Nefazodone's claimed advantages over other antidepressants available at the time included reduced possibility of disturbed sleep or sexual dysfunction, and ability to treat some patients who did not respond to other antidepressant drugs.


  1. "Nefazodone Prescribing Information", accessed 8 January 2007.]
  2. FDA Orange Book, accessed 15 January 2006.
  3. "Serzone Pulled from U.S. Market", accessed 15 January 2006.
  4. Sanchez, C, J. Hyttel (1999). Comparison of the Effects of Antidepressants and Their Metabolites on Reuptake of Biogenic Amines and on Receptor Binding. Celular and Molecular Neurobiology 19 (4): 467-89.
  5. [1]

Antidepressants (ATC N06A) edit
Monoamine oxidase inhibitors (MAOI) Harmaline, Iproclozide, Iproniazid, Isocarboxazid, Nialamide, Phenelzine, Selegiline, Toloxatone, Tranylcypromine
Reversible inhibitor of monoamine oxidase A (RIMA) Brofaromine, Moclobemide
Dopamine reuptake inhibitor (DARI) Amineptine, Phenmetrazine, Vanoxerine, Modafinil
Norepinephrine-dopamine reuptake inhibitors Bupropion
Norepinephrine reuptake inhibitor (NRI) or (NARI) Atomoxetine, Maprotiline, Reboxetine, Viloxazine
Serotonin-norepinephrine reuptake inhibitor (SNRI) Duloxetine, Milnacipran, Venlafaxine
Selective serotonin reuptake inhibitor (SSRI) Alaproclate, Etoperidone, Citalopram, Escitalopram, Fluoxetine, Fluvoxamine, Paroxetine, Sertraline, Zimelidine
Selective serotonin reuptake enhancer (SSRE) Tianeptine
Tricyclic antidepressants (TCA) Amitriptyline, Amoxapine, Butriptyline, Clomipramine, Desipramine, Dibenzepin, Dothiepin, Doxepin, Imipramine, Iprindole, Lofepramine, Melitracen, Nortriptyline, Opipramol, Protriptyline, Trimipramine
Tetracyclic antidepressants Maprotiline, Mianserin, Nefazodone, Trazodone
Noradrenergic and specific serotonergic antidepressant (NaSSA) Mirtazapine
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