What is the recommended dose of venlafaxine (Selective Serotonin and Norepinephrine Reuptake Inhibitor - SSNRI)?

Recommended Dosage of Venlafaxine (SSNRI)

The recommended starting dose for venlafaxine is 37.5 mg once or twice daily, with titration to a target dose of 75-225 mg/day for most conditions. 1, 2

Initial Dosing and Titration

• Starting dose: 37.5 mg once or twice daily 1
• Titration: Increase by 75 mg each week as tolerated 1
• Target dose: 75-225 mg/day for most conditions 1, 2
• Administration: Take with food in two or three divided doses 2

Dosing by Condition

Depression

• Initial dose: 75 mg/day in 2-3 divided doses 2
• Titration: Increase by up to 75 mg/day at intervals of no less than 4 days 2
• Maximum dose:
  • Outpatients: 225 mg/day is generally sufficient 2, 3
  • Inpatients/severe depression: May respond to higher doses up to 375 mg/day 2, 3

Neuropathic Pain

• Initial dose: 37.5 mg once or twice daily 1
• Target dose: 150-225 mg/day 1
• Duration of adequate trial: 4-6 weeks 1

Special Populations

Renal Impairment

• Mild to moderate impairment (GFR 10-70 mL/min): Reduce total daily dose by 25% 2
• Hemodialysis: Reduce total daily dose by 50% 2
• Note: Individual variability in clearance may necessitate personalized dosing 2

Hepatic Impairment

• Mild to moderate impairment: Reduce total daily dose by 50% 2
• Cirrhosis: May require greater than 50% reduction with individualized dosing 2

Elderly Patients

• No specific dose adjustment based on age alone, but consider starting at lower doses and titrating more slowly 2

Discontinuation

• Never discontinue abruptly due to risk of withdrawal symptoms 2
• Implement gradual dose reduction when discontinuing treatment 2
• If intolerable symptoms occur during discontinuation, resume previously prescribed dose and decrease more gradually 2

Clinical Considerations

• Venlafaxine at 75 mg/day is sufficient for the majority of cases 3
• Higher doses (>75 mg/day) are more commonly prescribed in inpatient settings and for more severely ill patients 3
• The dual action of inhibiting both serotonin and norepinephrine reuptake is dose-dependent, with norepinephrine inhibition becoming clinically relevant at higher doses 3
• Doses up to 600 mg/day have been studied and found tolerable, though with increased side effects 4

Common Side Effects

• Lower doses: Primarily serotonergic effects (nausea, headache)
• Higher doses: Additional noradrenergic effects (increased blood pressure, sweating)
• Most common side effects: Nausea, headache, dizziness, dry mouth, somnolence, and increased fatigue 4
• Blood pressure should be monitored, especially at higher doses 4

Drug Interactions

• MAOIs: Allow at least 14 days between discontinuing an MAOI and starting venlafaxine, and at least 7 days between stopping venlafaxine and starting an MAOI 2
• Tamoxifen: Venlafaxine has less impact on tamoxifen metabolism compared to some SSRIs (like fluoxetine and paroxetine) and may be preferred in patients taking tamoxifen 1

Venlafaxine's unique dual mechanism of action allows for dose-dependent targeting of symptoms, making it a versatile option for depression and neuropathic pain when properly dosed and monitored.