Generic Name

Venlafaxine Hydrochloride

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Classification

FDA Approved Indications

• Major depressive disorder
• Generalized anxiety disorder
• Social anxiety disorder
• Panic disorder

Mechanism of Action

Venlafaxine inhibits the reuptake of serotonin and norepinephrine, increasing their levels in the synaptic cleft, which contributes to its antidepressant and anxiolytic effects.

Dosage and Administration

Adult: Typically start at 75 mg/day, divided into 2-3 doses, with adjustments based on response and tolerability. Maximum dose is usually 225 mg/day.

Pediatric: Not approved for use in children and adolescents under 18 years.

Geriatric: Start at lower doses due to potential increased sensitivity and comorbidities, with careful titration.

Renal Impairment: Use with caution; dose adjustments may be necessary, especially with severe impairment.

Hepatic Impairment: Use with caution; start at lower doses and monitor closely.

Pharmacokinetics

Absorption: Well absorbed; food does not significantly affect absorption.

Distribution: Widely distributed; approximately 27% bound to plasma proteins.

Metabolism: Primarily metabolized in the liver via CYP2D6 to active metabolite O-desmethylvenlafaxine.

Excretion: Excreted primarily via urinary pathway; active metabolite also excreted in urine.

Half Life: Venlafaxine: about 5 hours; active metabolite: about 11 hours.

Contraindications

• Use of monoamine oxidase inhibitors (MAOIs) within 14 days.
• Hypersensitivity to venlafaxine.

Precautions

• History of hypertension, bleeding disorders, seizure disorders, increased risk of suicide, mania, or bipolar disorder. Monitor blood pressure and mental health closely. Use during pregnancy and lactation only if clearly needed.

Adverse Reactions - Common

• Nausea (Frequent)
• Dizziness (Frequent)
• Insomnia or sedation (Frequent)
• Dry mouth (Frequent)
• Sweating (Frequent)

Adverse Reactions - Serious

• Hypertension (Uncommon)
• Serotonin syndrome (Rare)
• Suicidal ideation or behavior (Uncommon in young adults and adolescents)
• Seizures (Rare)
• QT prolongation (Rare)

Drug-Drug Interactions

• Monoamine oxidase inhibitors (MAOIs), other serotonergic drugs (e.g., triptans, triptans, tryptophan, SNRI or SSRI antidepressants), anticoagulants, antiplatelet agents.

Drug-Food Interactions

• Alcohol should be avoided due to increased risk of CNS depression and hypertension.

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Do not discontinue abruptly; taper as advised.
• Report mood changes, suicidal thoughts, or side effects.
• Avoid alcohol and CNS depressants.
• Attend regular follow-up visits.

Special Considerations

Black Box Warnings:

• Increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults.
• Use with caution in patients with a history of hypertension or seizure disorders.

Genetic Factors: CYP2D6 poor metabolizers may have increased plasma levels.

Lab Test Interference: None significant.

Overdose Management

Signs/Symptoms: Dizziness, hallucinations, seizures, tachycardia, hypertension, somnolence.

Treatment: Supportive care, activated charcoal if ingestion was recent, airway management, seizure control, blood pressure management, and symptomatic treatment.

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F).

Stability: Stable for the duration of the expiration date.