What is the recommended dosing of Effexor (venlafaxine) in adults?

Venlafaxine (Effexor) Dosing in Adults

For adults with depression, venlafaxine should be started at 75 mg/day in 2-3 divided doses, then titrated up to 150-225 mg/day with a maximum dose of 375 mg/day. 1

Initial Dosing and Titration

• Starting dose: 75 mg/day, administered in two or three divided doses, taken with food 1
• Titration: Increase by 75 mg/day at intervals of no less than 4 days 1
• Target dose: 150-225 mg/day for most patients 1
• Maximum dose: 375 mg/day, generally in three divided doses 1

Dosing Considerations by Formulation

Immediate-Release (IR)

• Administer in 2-3 divided doses daily with food
• More frequent dosing may help reduce nausea and other side effects

Extended-Release (XR)

• Once-daily dosing (usually in the morning)
• May have fewer side effects than immediate-release formulation
• Equivalent efficacy to immediate-release when dosed appropriately

Dose Adjustments for Special Populations

Hepatic Impairment

• Mild to moderate impairment: Reduce total daily dose by 50% 1
• Severe impairment: Consider further dose reduction and individualization
• Monitor closely as there is significant variability in clearance among patients with hepatic impairment 1

Renal Impairment

• Mild to moderate impairment (GFR 10-70 mL/min): Reduce total daily dose by 25% 1
• Hemodialysis patients: Reduce total daily dose by 50% 1
• Individualize dosing due to variability in clearance 1

Elderly Patients

• No specific dose adjustment required based on age alone 1
• However, exercise caution when increasing the dose
• Consider starting at lower doses and titrating more slowly

Dosing for Specific Conditions

Major Depression

• Effective dose range: 75-375 mg/day 1
• Outpatients typically respond to 75-225 mg/day 1
• More severely depressed inpatients may require up to 350-375 mg/day 1

Neuropathic Pain

• Starting dose: 37.5 mg once or twice daily 2
• Titration: Increase by 75 mg each week 2
• Target dose: 150-225 mg/day 2
• Duration of adequate trial: 4-6 weeks 2

Monitoring and Follow-up

• Assess efficacy after 4-6 weeks of treatment at an adequate dose
• Monitor blood pressure regularly, as venlafaxine can cause increases in blood pressure, particularly at higher doses 2
• Watch for cardiac conduction abnormalities, especially in patients with pre-existing cardiac disease 2
• Taper gradually when discontinuing to avoid withdrawal syndrome 2

Common Pitfalls and Considerations

• Underdosing: Many patients are maintained on subtherapeutic doses (75 mg/day) when they might benefit from higher doses 3
• Blood pressure effects: Monitor blood pressure regularly, especially when using doses above 225 mg/day
• Withdrawal syndrome: Always taper gradually when discontinuing venlafaxine to prevent withdrawal symptoms 2
• Drug interactions: Use caution when combining with MAOIs, other serotonergic drugs, or CYP2D6 inhibitors
• Pregnancy: Use with caution during pregnancy, especially in the third trimester, as neonates may develop complications requiring prolonged hospitalization 1

Remember that while higher doses (up to 600 mg/day) have been used in clinical practice for treatment-resistant depression 4, the FDA-approved maximum dose is 375 mg/day, and doses above this level should be used with extreme caution and close monitoring.