Trazodone hydrochloride tablets are indicated for the treatment of depression. The efficacy of trazodone has been demonstrated in both inpatient and outpatient settings and for depressed patients with and without prominent anxiety.
Occasional low white blood cell and neutrophil counts have been noted in patients receiving trazodone hydrochloride. These were not considered clinically significant and did not necessitate discontinuation of the drug; however, the drug should be discontinued in any patient whose white blood cell count or absolute neutrophil count falls below normal levels. White blood cell and differential counts are recommended for patients who develop fever and sore throat (or other signs of infection) during therapy.
In vitro drug metabolism studies suggest that there is a potential for drug interactions when trazodone is given with CYP3A4 inhibitors. Ritonavir, a potent CYP3A4 inhibitor, increased the Cmax, AUC, and elimination half-life, and decreased clearance of trazodone after administration of ritonavir twice daily for 2 days. Adverse effects including nausea, hypotension, and syncope were observed when ritonavir and trazodone were coadministered. It is likely that ketoconazole, indinavir, and other CYP3A4 inhibitors such as itraconazole or nefazodone may lead to substantial increases in trazodone plasma concentrations, with the potential for adverse effects. If trazodone is used with a potent CYP3A4 inhibitor, a lower dose of trazodone should be considered.
Carbamazepine reduced plasma concentrations of trazodone when co-administered. Patients should be closely monitored to see if there is a need for an increased dose of trazodone when taking both drugs.
Increased serum digoxin or phenytoin levels have been reported to occur in patients receiving trazodone concurrently with either of those two drugs.
It is not known whether interactions will occur between monoamine oxidase (MAO) inhibitors and trazodone. Due to the absence of clinical experience, if MAO inhibitors are discontinued shortly before or are to be given concomitantly with trazodone, therapy should be initiated cautiously with gradual increase in dosage until optimum response is achieved.
Concurrent administration with electroshock therapy should be avoided because of the absence of experience in this area.
There have been reports of increased and decreased prothrombin time occurring in warfarinized patients who take trazodone.
No drug- or dose-related occurrence of carcinogenesis was evident in rats receiving trazodone hydrochloride in daily oral doses up to 300 mg/kg for 18 months.
Trazodone has been shown to cause increased fetal resorption and other adverse effects on the fetus in two studies using the rat when given at dose levels approximately 30 to 50 times the proposed maximum human dose. There was also an increase in congenital anomalies in one of three rabbit studies at approximately 15 to 50 times the maximum human dose. There are no adequate and well-controlled studies in pregnant women. Trazodone should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trazodone and/or its metabolites have been found in the milk of lactating rats, suggesting that the drug may be secreted in human milk. Caution should be exercised when trazodone is administered to a nursing woman.
Anyone considering the use of trazodone hydrochloride tablets in a child or adolescent must balance the potential risks with the clinical need.
Because the frequency of adverse drug effects is affected by diverse factors (e.g., drug dose, method of detection, physician judgment, disease under treatment, etc.) a single meaningful estimate of adverse event incidence is difficult to obtain. This problem is illustrated by the variation in adverse event incidence observed and reported from the inpatients and outpatients treated with trazodone. It is impossible to determine precisely what accounts for the differences observed.
Clinical Trial Reports
The table below is presented solely to indicate the relative frequency of adverse events reported in representative controlled clinical studies conducted to evaluate the safety and efficacy of trazodone hydrochloride.
The figures cited cannot be used to predict concisely the incidence of untoward events in the course of usual medical practice where patient characteristics and other factors often differ from those which prevailed in the clinical trials. These incidence figures, also, cannot be compared with those obtained from other clinical studies involving related drug products and placebo as each group of drug trials is conducted under a different set of conditions.
|Treatment-Emergent Symptom Incidence|
|Number of Patients||142||95||157||158|
|% of Patients Reporting|
|Shortness of Breath||*||1.1||1.3||0.0|
|Bad Taste in Mouth||1.4||0.0||0.0||0.0|
T = Trazodone Hydrochloride
P = Placebo
Occasional sinus bradycardia has occurred in long-term studies.
In addition to the relatively common (i.e., greater than 1%) untoward events enumerated above, the following adverse events have been reported to occur in association with the use of trazodone hydrochloride in the controlled clinical studies: akathisia, allergic reaction, anemia, chest pain, delayed urine flow, early menses, flatulence, hallucinations/delusions, hematuria, hypersalivation, hypomania, impaired speech, impotence, increased appetite, increased libido, increased urinary frequency, missed periods, muscle twitches, numbness, and retrograde ejaculation.
Although the following adverse reactions have been reported in trazodone users, the causal association has neither been confirmed nor refuted.
Voluntary reports received since market introduction include the following: abnormal dreams, agitation, alopecia, anxiety, aphasia, apnea, ataxia, breast enlargement or engorgement, cardiospasm, cerebrovascular accident, chills, cholestasis, clitorism, congestive heart failure, diplopia, edema, extrapyramidal symptoms, grand mal seizures, hallucinations, hemolytic anemia, hirsutism, hyperbilirubinemia, increased amylase, increased salivation, insomnia, leukocytosis, leukonychia, jaundice, lactation, liver enzyme alterations, methemoglobinemia, nausea/vomiting (most frequently), paresthesia, paranoid reaction, priapism (see WARNINGS and PRECAUTIONS, Information for Patients; some patients have required surgical intervention), pruritus, psoriasis, psychosis, rash, stupor, inappropriate ADH syndrome, tardive dyskinesia, unexplained death, urinary incontinence, urinary retention, urticaria, vasodilation, vertigo, and weakness.
Cardiovascular system effects which have been reported include the following: conduction block, orthostatic hypotension and syncope, palpitations, bradycardia, atrial fibrillation, myocardial infarction, cardiac arrest, arrhythmia, and ventricular ectopic activity, including ventricular tachycardia (see WARNINGS).