Nefazodone

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. On May 20, 2004, Bristol-Myers Squibb discontinued the sale of Serzone in the United States. Several generic formulations of nefazodone are still available.

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.

Dosing
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side effects can sometimes last for months, years or possibly indefinitely even after the drug has been completely withdrawn.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.

Advantages
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.