Nurses Compass
Drug Guide
Vilazodone Hydrochloride
Classification
Therapeutic: Antidepressant
Pharmacological: Selective Serotonin Reuptake Inhibitor (SSRI) and Serotonin 1A Receptor Partial Agonist
FDA Approved Indications
- Major depressive disorder (MDD)
Mechanism of Action
Vilazodone acts as a selective serotonin reuptake inhibitor and a partial agonist at the 5-HT1A receptor, resulting in increased serotonin levels in the synaptic cleft and modulation of serotonergic activity.
Dosage and Administration
Adult: Starting dose: 10 mg once daily for 7 days, then increase to 20 mg once daily. Dose can be adjusted based on response and tolerability.
Pediatric: Not approved for pediatric use.
Geriatric: Dose adjustments not specifically required, but caution advised due to potential increased sensitivity.
Renal Impairment: Use caution; no specific adjustment recommended but monitor closely.
Hepatic Impairment: Use with caution; consider starting at lower doses due to impaired hepatic metabolism.
Pharmacokinetics
Absorption: Well absorbed; food increases absorption.
Distribution: Bound to plasma proteins (approximately 96%).
Metabolism: Primarily hepatic via CYP3A4; some metabolism via CYP2C19 and CYP2D6.
Excretion: Metabolites excreted mainly in urine; some fecal excretion.
Half Life: Approximately 25 hours.
Contraindications
- Concurrent use with monoamine oxidase inhibitors (MAOIs) or history of hypersensitivity.
Precautions
- Risk of serotonin syndrome, especially with other serotonergic agents.
- Use with caution in patients with bleeding disorders or on anticoagulants.
- Monitor for worsening depression or suicidality, especially early in treatment.
Adverse Reactions - Common
- Gastrointestinal upset (nausea, diarrhea) (Common)
- Dry mouth (Common)
- Insomnia (Common)
- Dizziness (Common)
Adverse Reactions - Serious
- Serotonin syndrome (rare) (Serious)
- Hyponatremia, especially in elderly (Serious)
- Suicidal thoughts and behaviors (Serious)
Drug-Drug Interactions
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) may increase vilazodone levels.
- CYP3A4 inducers (e.g., rifampin, carbamazepine) may decrease efficacy.
Drug-Food Interactions
- Food increases absorption, so take with food as directed.
Drug-Herb Interactions
- St. John’s Wort may increase the risk of serotonin syndrome.
Nursing Implications
Assessment: Monitor for mood changes, suicidal ideation, response to medication, and adverse effects.
Diagnoses:
- Risk for suicide, Monitor for adverse drug reactions.
Implementation: Administer with food to enhance absorption; start with recommended dose and titrate based on response.
Evaluation: Assess improvement in depressive symptoms and monitor for adverse effects.
Patient/Family Teaching
- Take exactly as prescribed.
- Report any signs of serotonin syndrome (confusion, hallucination, seizure, extreme changes in blood pressure, increased heart rate, fever, excessive sweating, shivering or shaking, blurred vision, coordination problems, stomach cramp, persistent nausea/vomiting/diarrhea).
- Do not abruptly stop medication.
- Limit alcohol and avoid other serotonergic drugs unless approved by a healthcare provider.
Special Considerations
Black Box Warnings:
- Increased risk of suicidal thinking and behavior in children, adolescents, and young adults.
Genetic Factors: No specific genetic testing required.
Lab Test Interference: May cause false elevation of blood glucose or urinary 5-Hydroxyindoleacetic acid (5-HIAA) levels.
Overdose Management
Signs/Symptoms: Nausea, vomiting, tremor, somnolence, seizures, serotonin syndrome symptoms.
Treatment: Supportive care, activated charcoal if ingestion is recent, and monitoring in a medical setting. No specific antidote.
Storage and Handling
Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F).
Stability: Stable under recommended storage conditions.