nefazodone, Serzone

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GENERIC NAME: nefazodone

BRAND NAME: Serzone (This brand no longer is available in the U.S.)

DRUG CLASS AND MECHANISM: Nefazodone is an oral antidepressant drug that 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. Compared with trazodone, nefazodone has a lesser risk of priapism (prolonged penile erection). The FDA approved nefazodone in December 1994.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 50, 100, 150, 200, and 250 mg.

STORAGE: Tablets of nefazodone should be kept at room temperature, below 40 C (104 F).

PRESCRIBED FOR: Nefazodone is used for the treatment of depression.

DOSING: The recommended dose range is 150-300 mg twice daily. The maximum dose is 600 mg daily. 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.

DRUG INTERACTIONS: 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.

PREGNANCY: There are no adequate studies of nefazodone in pregnant women.

NURSING MOTHERS: Nefazodone may be secreted in breast milk and may cause adverse effects in the nursing infant.




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