What is the recommended dosing for Effexor (venlafaxine)?

Venlafaxine (Effexor) Dosing Guidelines

The recommended starting dose for venlafaxine is 75 mg/day, administered in two or three divided doses, taken with food. The dose may be increased to 150 mg/day based on tolerability and clinical need, with further increases up to 225 mg/day if necessary. 1

Initial Dosing

• Starting dose: 75 mg/day (in 2-3 divided doses with food)
• Titration: Increase by up to 75 mg/day at intervals of no less than 4 days
• Target dose range: 75-225 mg/day for most patients
• Maximum dose: 375 mg/day (generally in three divided doses)

Dosing Considerations Based on Patient Factors

Hepatic Impairment

• Mild to moderate impairment: Reduce total daily dose by 50%
• Severe impairment: May require even greater dose reduction
• Note: Individual variability in clearance makes individualization of dosing advisable 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%
• Note: Significant individual variability may require personalized dosing 1

Elderly Patients

• No specific dose adjustment based on age alone
• Exercise caution when increasing the dose
• Start at lower doses and titrate more slowly 1

Extended-Release Formulation

For venlafaxine XR (extended-release):

• Can be administered once daily
• Similar efficacy to immediate-release formulation
• May have better tolerability profile 2

Treatment Duration

• Acute episodes: Several months of sustained therapy beyond initial response
• Maintenance treatment: Continued therapy at the same effective dose has demonstrated efficacy in preventing relapse 1

Discontinuation

• Gradual tapering rather than abrupt cessation is strongly recommended
• Monitor for discontinuation symptoms (dizziness, nausea, headache, irritability)
• If intolerable symptoms occur, resume previous dose and decrease more gradually 1

Special Warnings

• Pregnancy (third trimester): Carefully consider risks/benefits due to potential neonatal complications
• MAOIs: Allow at least 14 days between discontinuing MAOIs and starting venlafaxine, and at least 7 days between stopping venlafaxine and starting MAOIs 1

Common Side Effects to Monitor

• Digestive: nausea, dry mouth
• Nervous system: dizziness, somnolence, insomnia
• Urogenital: abnormal ejaculation
• Other: sweating 2
• Blood pressure increases may occur, particularly at higher doses 3

Clinical Pearls

• Higher doses (≥375 mg/day) may be beneficial for treatment-resistant depression or severely depressed inpatients 1, 4
• Therapeutic response may be evident as early as week 2 of treatment 2
• Venlafaxine at 150 mg/day may be superior to fluoxetine in patients who do not respond early to treatment 5
• Blood pressure monitoring is recommended, especially at higher doses 3, 4

Common Pitfalls to Avoid

• Inadequate initial dosing (starting below 75 mg/day may be less effective)
• Insufficient time for response evaluation (allow at least 2-4 weeks at therapeutic dose)
• Abrupt discontinuation (always taper gradually)
• Failure to monitor blood pressure, especially at doses above 225 mg/day
• Not accounting for renal or hepatic impairment when determining dosage

By following these dosing guidelines and monitoring parameters, venlafaxine can be an effective treatment option for major depression with a manageable side effect profile.