Initial Dosing of Venlafaxine (Effexor) for Adults
The initial dosing of venlafaxine (Effexor) for adults is 37.5 mg once or twice daily, with gradual titration by 75 mg each week to an effective dose, typically 150-225 mg/day. 1
Dosing Algorithm
Starting Dose
- Initial dose: 37.5 mg once or twice daily 1
- Take with food to improve tolerability 2
- Available in both immediate-release and extended-release formulations
Titration Schedule
- Increase by 75 mg each week 1
- Allow at least 4 days between dose increases 2
- Titration typically requires 2-4 weeks to reach efficacious dosage 1
Target Dose Range
- Effective dose range: 150-225 mg/day for most patients 1
- Maximum recommended dose: 375 mg/day 2
- For outpatients with moderate depression: doses greater than 225 mg/day showed no additional benefit 2
- For severely depressed inpatients: mean effective dose of 350 mg/day 2
Special Populations and Dose Adjustments
Hepatic Impairment
- Reduce total daily dose by 50% in mild to moderate hepatic impairment 2
- Further dose reduction may be necessary in cirrhosis 2
- Individualize dosing due to variable clearance 2
Renal Impairment
- Reduce total daily dose by 25% in mild to moderate renal impairment (GFR 10-70 mL/min) 2
- Reduce total daily dose by 50% in patients on hemodialysis 2
- Individualize dosing due to variable clearance 2
Elderly Patients
- No specific dose adjustment required based on age alone 2
- Exercise caution when increasing the dose 2
- Consider starting at the lower end of the dosing range
Monitoring and Precautions
Cardiovascular Monitoring
- Use with caution in patients with cardiac disease 1
- Monitor for cardiac conduction abnormalities and blood pressure increases 1
- Consider baseline ECG for patients with cardiac risk factors
Discontinuation
- Taper venlafaxine when discontinuing treatment 1
- Withdrawal syndrome can occur with abrupt discontinuation 1
- Gradual tapering over 10-14 days is recommended to minimize withdrawal symptoms
Duration of Treatment
Acute Phase
- Adequate trial duration: 4-6 weeks 1
- Assess efficacy and tolerability during this period
Maintenance Treatment
- For recurrent depression, continued treatment at the same effective dose has been shown to prevent relapse 2
- Long-term efficacy demonstrated in maintenance studies of up to 52 weeks 2
Common Side Effects
- Nausea (most common)
- Dizziness
- Somnolence
- Sweating
- Blood pressure increases (particularly at higher doses)
Venlafaxine has shown efficacy in painful diabetic neuropathy and polyneuropathies but not in postherpetic neuralgia. When prescribing for patients with cardiac disease, careful monitoring is essential due to potential cardiac conduction abnormalities and blood pressure increases that have been reported in some patients.