Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: trazodone

BRAND NAME: Desyrel

DRUG CLASS AND MECHANISM: Trazodone is an oral antidepressant drug that affects the chemical messengers (neurotransmitters) within the brain that nerves use to communicate with (stimulate) each other. The major neurotransmitters are acetylcholine, norepinephrine, dopamine and serotonin. Many experts believe that an imbalance among the different neurotransmitters is the cause of depression. Although the exact mechanism of action of trazodone is unknown, it probably improves symptoms of depression by inhibiting the uptake of serotonin by nerves in the brain. This results in more serotonin to stimulate other nerves. Trazodone also may increase directly the action of serotonin. Trazodone is chemically unrelated to the selective serotonin reuptake inhibitors (SSRIs), the tricyclic antidepressants (TCAs) or the monoamine oxidase inhibitors (MAO inhibitors). It is chemically related to nefazodone (Serzone) and shares its actions. Trazodone was approved by the FDA in 1982.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 50, 100, 150, and 300 mg

STORAGE: Store at room temperature, 15-30°C (59-86°F)

PRESCRIBED FOR: Trazodone is primarily used for the treatment of depression. It is sometimes prescribed as a sedative, and it also is used in combination with other drugs for the treatment of panic attacks, aggressive behavior, agoraphobia, and cocaine withdrawal.

DOSING: For the treatment of depression, the dose for adults is 150-600 mg per day. The initial starting dose usually is 150 mg per day. Trazodone is given in one or more daily doses, sometimes with the largest dose at night. As with all antidepressants, it may take several weeks for the full effects of treatment to be seen. Doses often are adjusted slowly upwards to find the optimal dose. Elderly patients and debilitated persons may need lower doses. Trazodone should be taken after a meal or light snack to reduce the risk of dizziness. Food also increases the amount of drug absorbed into the body. Doses of 25-75 mg are prescribed for insomnia.

DRUG INTERACTIONS: All antidepressants that increase concentrations of serotonin in the brain, including trazodone, should not be taken with MAO-inhibitors. Drugs in the MAO-inhibitor class include isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane). Such combinations may lead to confusion, high blood pressure and tremor. This same type of interaction may occur when trazodone is used with selegiline (Eldepryl). If a patient is switched from trazodone to an MAO inhibitor, at least one week should be allowed after stopping trazodone before the MAO inhibitor is begun. After stopping an MAO inhibitor, two weeks should elapse before starting trazodone.

Increased blood concentrations of digoxin and phenytoin (Dilantin) have been reported in persons taking trazodone due to a decrease in the metabolism (break-down and elimination) of these drugs by trazodone.

Carbamazepine (Tegretol) may decrease blood levels of trazodone by increasing its elimination from the body. Ketoconazole (Nizoral), ritonavir (Norvir), and indinavir (Crixivan) inhibit the breakdown of trazodone leading to increased blood levels of trazodone and potential side effects.

PREGNANCY: There are no adequate studies of trazodone in pregnant women. Studies in animals have demonstrated effects on the developing fetus. Trazodone should only be used during pregnancy if the physician feels that its benefits outweigh its potential risks.

NURSING MOTHERS: Trazodone is secreted in breast milk. Therefore, caution should be used in prescribing trazodone to women who are breastfeeding.

SIDE EFFECTS: The most common side effects associated with trazodone are nausea, dizziness, insomnia, agitation, tiredness, dry mouth, constipation, lightheadedness, headache, low blood pressure, blurred vision, and confusion. Priapism (including clitoral priapism in women), a painful condition in which the penis (or clitoris) remains in an erect position for a prolonged period, has been reported in patients receiving trazodone. Priapism occasionally results in permanent impairment of erectile function or impotence. Patients should be warned of the possibility of priapism and told to discontinue the drug at once and consult with their physician if this reaction occurs. Trazodone also may affect ejaculation, orgasm and libido.

Antidepressants increased the risk of suicidal thinking and behavior (suicidality) in short-term studies in children and adolescents with depression and other psychiatric disorders. Anyone considering the use of trazodone or any other antidepressant in a child or adolescent must balance this risk with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidality, or unusual changes in behavior.

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