What is the recommended dosage and treatment regimen for Effexor (venlafaxine)?

Recommended Dosage and Treatment Regimen for Effexor (Venlafaxine)

For most patients with depression, venlafaxine should be initiated at 75 mg/day in two or three divided doses taken with food, with gradual titration up to 150-225 mg/day based on response and tolerability. 1

Initial Dosing and Titration

Standard Dosing for Depression:

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

Extended-Release (XR) Formulation:

• Starting dose: 75 mg once daily
• Titration: Can increase to 150 mg once daily after 1-2 weeks if needed
• Maximum dose: 225 mg once daily 2, 3

Special Population Considerations

Hepatic Impairment:

• Mild to moderate impairment: Reduce total daily dose by 50%
• Severe impairment: May require further 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% 1

Elderly Patients:

• No specific dose adjustment based on age alone
• Consider lower starting doses and slower titration
• Exercise caution when increasing the dose 1

Duration of Treatment

• Acute phase: 6-8 weeks to achieve full response
• Maintenance phase: Several months or longer beyond response to acute episode
• Studies have demonstrated efficacy in maintaining antidepressant response for up to 52 weeks 1

Specific Indications and Dosing

For Neuropathic Pain:

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

Administration Considerations

Immediate-Release (IR) vs. Extended-Release (XR):

• XR formulation has shown superior efficacy over IR at equivalent daily doses 3
• XR formulation allows for once-daily dosing, potentially improving adherence
• IR formulation may be given once daily in some patients, though twice-daily dosing may provide more rapid initial response 5

Discontinuation

• Never discontinue abruptly due to risk of withdrawal symptoms
• Implement gradual dose reduction whenever possible
• If intolerable symptoms occur during discontinuation, resume previously prescribed dose and decrease more gradually 1

Monitoring and Side Effects

Common Side Effects:

• Nausea (most common, especially in first 2 weeks)
• Headache
• Dizziness
• Somnolence
• Insomnia
• Sweating 2

Cardiovascular Monitoring:

• Monitor blood pressure regularly
• Cardiac conduction abnormalities have been reported in a small number of patients
• Use with caution in patients with cardiac disease 4

Important Precautions

• 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
• Taper when discontinuing to prevent withdrawal syndrome 4
• Pregnancy (third trimester): Consider risks and benefits carefully as neonates may develop complications requiring prolonged hospitalization 1

Venlafaxine's dual mechanism of inhibiting both serotonin and norepinephrine reuptake contributes to its efficacy in depression and certain pain conditions, with dosing requirements that should be carefully adjusted based on individual response and tolerability.