Overview
11 DESCRIPTION Trazodone hydrochloride is a selective serotonin reuptake inhibitor and 5HT2 receptor antagonist. Trazodone hydrochloride, USP is a triazolopyridine derivative designated as 2-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]- 1,2,4-triazolo[4, 3-a]pyridin-3(2H)-one hydrochloride. It is a white to off-white, crystalline powder which is sparingly soluble in chloroform and in water.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The mechanism of trazodone's antidepressant action is not fully understood, but is thought to be related to its enhancement of serotonergic activity in the CNS. Trazodone is both a selective serotonin reuptake inhibitor (SSRI) and a 5HT2 receptor antagonist and the net result of this action on serotonergic transmission and its role in trazodone's antidepressant effect is unknown. 12.2 Pharmacodynamics Preclinical studies have shown that trazodone selectively inhibits neuronal reuptake of serotonin (Ki = 367 nM) and acts as an antagonist at 5-HT-2A (Ki = 35.6 nM) serotonin receptors. Trazodone is also an antagonist at several other monoaminergic receptors including 5-HT2B (Ki = 78.
Indications
- 1 INDICATIONS AND USAGE Trazodone is a selective serotonin reuptake inhibitor indicated for the treatment of major depressive disorder (MDD) ( 1 ). Trazodone hydrochloride tablets are indicated for the treatment of major depressive disorder (MDD) in adults.
Common Doses
- 150 mg
- 50 mg
- 400 mg
- 600 mg
Dosage
2 DOSAGE AND ADMINISTRATION Starting dose: 150 mg in divided doses daily. May be increased by 50 mg per day every three to four days. Maximum dose: 400 mg per day in divided doses ( 2 ). Trazodone hydrochloride tablets should be taken shortly after a meal or light snack ( 2 ). Tablets should be swallowed whole or broken in half along the score line, and should not be chewed or crushed ( 2 ). When discontinued, gradual dose reduction is recommended ( 2 ). 2.1 Dose Selection An initial dose of 150 mg/day in divided doses is suggested.
Black Box Warning
WARNING: SUICIDAL THOUGHTS and BEHAVIORS Antidepressants increased the risk of suicidal thoughts and behaviors in pediatric and young adult patients in short-term studies. Closely monitor all antidepressant-treated patients for clinical worsening, and for emergence of suicidal thoughts and behaviors [see Warnings and Precautions ( 5.1 )] . Trazodone is not approved for use in pediatric patients [see Use in Specific Populations ( 8.4 )] . WARNING: SUICIDAL THOUGHTS and BEHAVIORS See full prescribing information for complete boxed warning.
Contraindications
- 4 CONTRAINDICATIONS None ( 4 ). Concomitant use of monoamine oxidase inhibitors (MAOIs), or use within 14 days of stopping MAOIs ( 4 ). Trazodone hydrochloride tablets are contraindicated in: Patients taking, or within 14 days of stopping, monoamine oxidase inhibitors (MAOIs), including MAOIs such as linezolid or intravenous methylene blue, because of an increased risk of serotonin syndrome [see Warnings and Precautions ( 5.2 ), Drug Interactions ( 7.1 )].
Side Effects
- 6 ADVERSE REACTIONS Most common adverse reactions (incidence ≥ 5% and twice that of placebo) are: edema, blurred vision, syncope, drowsiness, fatigue, diarrhea, nasal congestion, weight loss ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Zydus Pharmaceuticals (USA) Inc. at 1-877-993-8779 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. The following serious adverse reactions are described elsewhere in the labeling: Suicidal Thoughts and Behavior in Children, Adolescents and Young Adults [see Boxed Warning and Warnings and Precautions ( 5.
Interactions
- 7 DRUG INTERACTIONS CNS Depressants: Trazodone may enhance effects of alcohol, barbiturates, or other CNS depressants ( 7 ). CYP3A4 Inhibitors: Consider trazodone dose reduction based on tolerability ( 2.5 , 7 ). CYP3A4 Inducers: Increase in trazodone dosage may be necessary ( 2.5 , 7 ). Digoxin or Phenytoin: Monitor for increased digoxin or phenytoin serum levels ( 7 ). Warfarin: Monitor for increased or decreased prothrombin time ( 7 ). MAOIs MAOIs should not be used within 14 days of trazodone [see Warnings and Precautions ( 5.8 )].