What is nefazodone, and how does it work (mechanism of action)?
Nefazodone is an oral antidepressant drug.
Nefazodone affects chemicals in the brain that nerves use to send messages to
one another, called neurotransmitters. The neurotransmitters that are released
by nerves are taken up again by the nerves that release them for reuse. Many
experts believe that
depression is caused by an imbalance among the amounts of neurotransmitters
that are released. Nefazodone works by inhibiting the uptake by nerves of
serotonin and norepinephrine, two neurotransmitters, resulting in more serotonin
and norepinephrine to transmit messages to other nerves. Nefazodone is
chemically unrelated to the serotonin reuptake inhibitors (SSRIs), the
tricyclic antidepressants (TCAs), or the
monoamine oxidase (MAO) inhibitors. It is
chemically related to another antidepressant,
trazodone
(Desyrel) and shares its actions. The FDA approved nefazodone in December 1994.
What brand names are available for nefazodone?
Serzone (This brand no longer is available in the U.S.)
Is nefazodone available as a generic drug?
Yes
Do I need a prescription for nefazodone?
Yes
What are the side effects of nefazodone?
The most commonly noted side effects associated with nefazodone
are nausea,
dizziness,
insomnia,
agitation, tiredness,
dry mouth,
constipation, lightheadedness,
blurred vision,
and confusion. Rarely, nefazodone is associated with priapism or prolonged
penile erection. Compared with trazodone, nefazodone has a lesser risk of
priapism (prolonged penile erection). Although the erection usually subsides
eventually, occasionally
blood clots
form within the penis and cause serious damage to the penis. Nefazodone rarely
may cause liver failure that may result in liver transplantation.
If antidepressants are discontinued abruptly, symptoms may occur such as
dizziness, headache,
nausea, changes in mood, or changes in the sense of smell, taste, etc. (Such
symptoms even may occur when even a few doses of antidepressant are missed.)
Therefore, it is recommended that the dose of antidepressant be reduced
gradually when therapy is discontinued.
Antidepressants increased the risk of suicidal thinking and behavior in
short-term studies in children and
adolescents
with depression and other psychiatric disorders. Anyone considering the use
of nefazodone or any other antidepressant in a child or adolescent must balance
this risk of suicide
with the clinical need. Patients who are started on therapy should be closely
observed for clinical worsening, suicidal thoughts, or unusual changes in
behavior.
What is the dosage for nefazodone?
The recommended dose range is 150-300 mg twice daily. The maximum
dose is 600 mg daily. The starting dose is 100 mg twice daily. Doses may be
increased weekly by 100 to 200 mg day in two divided doses. As with all
antidepressants, the full effect may take a few weeks to become manifest. Doses
are often adjusted slowly upward to find the optimal dose. Elderly patients and
debilitated persons may need lower doses.
Which drugs or supplements interact with nefazodone?
All antidepressants whose actions include increasing brain concentrations of serotonin, including nefazodone, should not be taken with any of the MAO (monoamine oxidase) inhibitor class of antidepressants, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), procarbazine (Matulane), and selegiline (Eldepryl). Such combinations may lead to confusion, high blood pressure, tremor, and increased activity. If a patient is switched from nefazodone to an MAO inhibitor, at least one week should be allowed after stopping nefazodone before starting the MAO inhibitor. Two weeks should be allowed between stopping an MAO inhibitor and initiating treatment with nefazodone.
Nefazodone may increase the blood concentration of several drugs by reducing their removal by the liver. Through this mechanism nefazodone may markedly increase the blood concentrations of triazolam (Halcion) and alprazolam (Xanax), resulting in excessive sedation and impaired ability to perform tasks. It is recommended that people taking triazolam who need to be started on nefazodone should have their triazolam dose reduced by 75%. Similarly, those people taking alprazolam who need to take nefazodone should have their alprazolam dose reduced by 50%. Nefazodone also may increase the blood concentration and possibly the side effects of eletriptan (Relpax), eplerenone (Inspra), pimozide (Orap), ranolazine (Ranexa), and silodosin (Rapaflo).
Carbamazepine (Tegretol, Tegretol XR, Equetro, Carbatrol) may decrease nefazodone blood levels and possibly its effectiveness by increasing nefadone's removal by the liver. Conversely, nefazodone may increase the levels of carbamazepine, possibly leading to toxicity, by decreasing the removal of carbamazepine by the liver.
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Is nefazodone safe to take if I’m pregnant or breastfeeding?
Nefazodone may be secreted in
breast milk
and may cause adverse effects in the nursing infant.
What else should I know about nefazodone?
What preparations of nefazodone are available?
PREPARATIONS: Tablets: 50, 100, 150, 200, and 250 mg.
How should I keep nefazodone stored?
Tablets of nefazodone should be kept at room temperature, below 40 C
(104 F).