Generic Name

Desvenlafaxine fumarate

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Classification

FDA Approved Indications

• Major depressive disorder

Mechanism of Action

Inhibits the reuptake of serotonin and norepinephrine, increasing their levels in the synaptic cleft, which helps elevate mood and alleviate depression symptoms.

Dosage and Administration

Adult: Start at 50 mg once daily. Dose may be adjusted between 50-400 mg/day based on response and tolerability.

Pediatric: Not approved for pediatric use.

Geriatric: No specific dose adjustment; monitor for tolerability.

Renal Impairment: Adjust dose in severe renal impairment (CrCl <30 mL/min). Typically, a starting dose of 50 mg daily is recommended.

Hepatic Impairment: Use with caution; monitor for adverse effects, and consider a lower dose due to decreased metabolism.

Pharmacokinetics

Absorption: Well absorbed after oral administration.

Distribution: Moderately bound to plasma proteins.

Metabolism: Primarily via conjugation to inactive metabolites; minimal CYP450 involvement.

Excretion: Excreted mainly in urine as unchanged drug and metabolites.

Half Life: About 11 hours.

Contraindications

• Use with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing an MAOI.
• Known hypersensitivity to venlafaxine or desvenlafaxine.

Precautions

• History of hypertension, seizure disorders, or bleeding disturbances.
• Increase in blood pressure observed in some patients; monitor BP regularly.

Adverse Reactions - Common

• Nausea (Common)
• Dizziness (Common)
• Sweating (Common)
• Dry mouth (Common)

Adverse Reactions - Serious

• Hypertension (Less common)
• Serotonin syndrome (Rare but serious)
• Suicidal thoughts or behavior in young adults and adolescents (Serious)

Drug-Drug Interactions

• Other serotonergic drugs, like SSRIs, SNRIs, triptans, tramadol, lithium, etc.
• Inhibitors of CYP3A4.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication as prescribed, even if feeling well.
• Report adverse effects such as increased blood pressure, mood changes, or suicidal thoughts.
• Avoid alcohol and caution regarding driving until response is known.

Special Considerations

Black Box Warnings:

• Increased risk of suicidal thinking and behavior in children, adolescents, and young adults.
• Serotonin syndrome risk with serotonergic drugs.

Genetic Factors: Genetic variations may influence metabolism and response.

Lab Test Interference: May affect blood pressure and serotonin levels.

Overdose Management

Signs/Symptoms: Dizziness, tachycardia, vomiting, somnolence, seizures.

Treatment: Supportive care, activated charcoal if ingested recently, seizure management; dialysis is generally not effective.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable under recommended storage conditions.