Pill Identification & Overview
A white, round pill debossed with “8” on the upper half and “05” on the lower half of a score line (bisect) is Trazodone Hydrochloride 50 mg.
Characteristic – Specification
- Active Ingredient – Trazodone Hydrochloride
- Strength – 50 mg
- Drug Class – Serotonin Antagonist and Reuptake Inhibitor (SARI)
- Color & Shape – White to off-white, round, biconvex tablet with beveled edges
- Imprint / Markings – “8” above bisect line, “05” below bisect line; reverse side is plain
- Scoring – Bisected (scored), allowing it to be split into two 25 mg doses
- Common Manufacturers – Accord Healthcare / Zydus Pharmaceuticals
- Controlled Status – Prescription only (Rx-only); non-controlled substance
Mechanism of Action (Pharmacology)
Trazodone functions primarily as a Serotonin Antagonist and Reuptake Inhibitor (SARI). Its pharmacological activity varies depending on the dosage administered:
- Receptor Blockade: At low to moderate doses, trazodone acts as a potent antagonist at serotonin receptors. Blocking contributes to its anxiolytic and sleep-promoting effects without causing the sexual dysfunction or motor agitation often seen with SSRIs.
- Serotonin Reuptake Inhibition (SERT): At higher therapeutic doses (typically 150 mg to 300+ mg/day), trazodone inhibits the serotonin reuptake transporter, increasing extracellular serotonin concentrations in synaptic clefts.
- Adrenergic Antagonism: Trazodone exerts moderate-to-high antagonistic activity at histamine adrenergic receptors. This antagonism explains its prominent sedative properties and propensity to cause orthostatic lightheadedness.
Therapeutic Indications & Dosage
Approved & Off-Label Uses
- Major Depressive Disorder (MDD): FDA-approved for the treatment of depression in adults.
- Insomnia (Off-Label): Widely prescribed at low doses (25 mg to 100 mg) off-label as a non-habit-forming sleep aid to improve sleep onset and sleep maintenance.
- Anxiety & Agitation (Off-Label): Occasionally used for generalized anxiety disorders or agitation in specific patient populations.
Typical Dosage Guidelines
- For Major Depressive Disorder:
- Starting dose: 150 mg/day in divided doses.
- Titration: Can be increased by 50 mg/day every 3 to 7 days.
- Maximum dose: Up to 400 mg/day for outpatients; up to 600 mg/day in severe hospitalized cases.
- For Insomnia (Off-Label):
- Starting dose: 25 mg (half of an “8 05” tablet) to 50 mg taken 30 to 60 minutes before bedtime.
- Administration Advice: Take with or immediately after a meal or light snack to increase absorption and minimize dizziness or stomach irritation.
Side Effects Profile
Common Side Effects
- Drowsiness, excessive somnolence, and “morning hangover” sedation
- Dizziness and lightheadedness (especially upon standing)
- Dry mouth (xerostomia)
- Blurred vision
- Headache and fatigue
- Nausea, constipation, or mild gastrointestinal distress
Serious Side Effects (Require Immediate Medical Attention)
- Orthostatic Hypotension & Syncope: Sharp drop in blood pressure upon standing due to blockade.
- Cardiac Arrhythmias / QT Prolongation: Can prolong the QT interval, potentially causing ventricular arrhythmias such as Torsades de Pointes.
- Priapism: A rare but severe adverse event characterized by prolonged, painful penile erections occurring in the absence of sexual stimulation. If untreated for greater than 4 hours, permanent erectile dysfunction or tissue damage can occur.
- Bleeding Complications: Impairment of platelet serotonin uptake increases the risk of upper gastrointestinal and mucosal bleeding.
Precautions & Drug Interactions
- CNS Depressants & Alcohol: Concurrent use with alcohol, benzodiazepines, opioids, or sedating antihistamines causes severe additive central nervous system and respiratory depression.
- CYP3A4 Inhibitors & Inducers: Trazodone is metabolized primarily in the liver by CYP3A4. Strong inhibitors (e.g., ketoconazole, clarithromycin) increase trazodone levels and toxicity risk, while inducers (e.g., carbamazepine, St. John’s Wort) decrease efficacy.
- Anticoagulants & NSAIDs: Concomitant use with NSAIDs, aspirin, or warfarin heightens the risk of gastrointestinal bleeding.
- Discontinuation Syndrome: Stopping trazodone abruptly can cause withdrawal symptoms, including rebound insomnia, agitation, and nausea. Tapering under medical guidance is recommended.
Boxed Warning & Critical Safety Warnings
FDA Black Box Warning: Suicidal Thoughts and Behaviors
Like all antidepressants, trazodone carries an FDA black box warning regarding an increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults (up to age 24). Patients should be closely monitored for worsening clinical depression, agitation, or unusual changes in behavior.
- Serotonin Syndrome: Co-administration with other serotonergic agents (such as MAOIs, SSRIs, SNRIs, or triptans) can trigger life-threatening serotonin toxicity. Symptoms include mental status changes (confusion, delirium), autonomic instability (tachycardia, hyperthermia, diaphoresis), and neuromuscular abnormalities (tremors, hyperreflexia, clonus). A 14-day washout period is required when switching between MAOIs and trazodone.
- Activation of Mania/Hypomania: In individuals with undiagnosed bipolar disorder, antidepressant monotherapy can trigger manic or hypomanic episodes.
- Angle-Closure Glaucoma: Pupillary dilation triggered by trazodone can precipitate an angle-closure attack in patients with anatomically narrow anterior chamber angles.