What is the recommended dosing for Effexor (venlafaxine)?

Venlafaxine (Effexor) Dosing Guidelines

The recommended starting dose for venlafaxine (Effexor) is 75 mg/day, administered in two or three divided doses, taken with food. 1

Initial Dosing and Titration

• Starting dose: 75 mg/day (divided into 2-3 doses with food)
• Titration: Dose may be increased to 150 mg/day based on clinical response and tolerability
• Further increases: If needed, dose can be further increased up to 225 mg/day
• Titration intervals: When increasing the dose, increments of up to 75 mg/day should be made at intervals of no less than 4 days 1
• Maximum dose: 375 mg/day (generally in three divided doses) for severely depressed patients 1

Dose-Response Relationship

Venlafaxine demonstrates a clear dose progression:

• At lower doses (75 mg/day): Predominantly affects serotonin reuptake
• At higher doses (≥150 mg/day): Increasingly affects norepinephrine reuptake as well 2
• Clinical evidence shows that 75 mg/day is the minimum effective dose 3
• More severely depressed inpatients may respond better to higher doses (mean 350 mg/day) 1

Special Populations

Hepatic Impairment

• Mild to moderate impairment: Reduce total daily dose by 50%
• Cirrhosis: May require >50% dose reduction with individualized dosing 1

Renal Impairment

• Mild to moderate impairment (GFR 10-70 mL/min): Reduce total daily dose by 25%
• Hemodialysis patients: Reduce total daily dose by 50%
• Individualization of dosing may be necessary 1

Elderly Patients

• No specific dose adjustment based on age alone
• Exercise caution when treating elderly patients
• Consider starting at lower doses and titrating more slowly 1

Pregnant Women (Third Trimester)

• Carefully consider risks and benefits
• Neonates exposed to venlafaxine late in the third trimester may develop complications requiring prolonged hospitalization, respiratory support, and tube feeding 1

Maintenance Treatment

• Long-term efficacy has been demonstrated in maintenance treatment
• Patients may require the same dose for maintenance as needed for initial response
• Periodic reassessment is recommended to determine the need for continued treatment 1

Discontinuation

• Gradual dose reduction is recommended rather than abrupt cessation
• Monitor for discontinuation symptoms (dizziness, nausea, headache, irritability, insomnia)
• If intolerable symptoms occur during discontinuation, consider resuming the previously prescribed dose and decreasing more gradually 1

Important Monitoring Considerations

• Blood pressure monitoring is recommended, especially at doses above 150 mg/day, as venlafaxine can increase blood pressure 4, 2
• At higher doses, watch for potential side effects including:
  • Nausea, dry mouth, dizziness
  • Somnolence, insomnia
  • Sexual dysfunction
  • Diaphoresis
  • Tachycardia, tremors, anxiety 2, 5

Drug Interactions

• Allow at least 14 days between discontinuation of an MAOI and initiation of venlafaxine
• Allow at least 7 days after stopping venlafaxine before starting an MAOI 1
• Venlafaxine has a favorable drug-drug interaction profile with low protein binding and minimal inhibition of CYP enzymes 2

Venlafaxine's effectiveness is dose-dependent, with evidence suggesting that higher doses may provide greater efficacy in treatment-resistant cases. The medication's dual mechanism of action (affecting both serotonin and norepinephrine) makes it particularly useful for patients with depression who have not responded adequately to SSRIs alone.