What is the common dosage of Effexor (venlafaxine) and what is it used for?

Venlafaxine (Effexor): Common Dosage and Indications

Primary Indication

Venlafaxine is FDA-approved for major depressive disorder and generalized anxiety disorder, with a starting dose of 75 mg/day (divided into 2-3 doses with food for immediate-release formulation), titrating up to a target therapeutic range of 150-225 mg/day. 1

Standard Dosing Regimen

Immediate-Release Formulation

• Starting dose: 75 mg/day divided into 2-3 doses, taken with food 1
• Initial titration: Increase to 150 mg/day based on tolerability and clinical need 1
• Target therapeutic range: 150-225 mg/day for most patients 2, 3
• Maximum dose: 375 mg/day for severely depressed patients (generally in three divided doses) 1
• Titration intervals: Increase by up to 75 mg/day at intervals of no less than 4 days 1

Extended-Release Formulation

• Starting dose: 37.5 mg once or twice daily 3
• Titration schedule: Increase by 75 mg weekly as tolerated 3
• Target dose: 150-225 mg/day 3
• Maximum outpatient dose: 225 mg/day for routine depression 3
• Severe depression: Up to 375 mg/day may be needed 3

FDA-Approved Indications

Major Depressive Disorder

• Primary indication with demonstrated efficacy at 75-375 mg/day 1, 4
• More severely depressed inpatients may require higher doses (mean 350 mg/day) 1
• Outpatients with moderate depression show no additional benefit beyond 225 mg/day 1

Generalized Anxiety Disorder

• FDA-approved indication 4, 5
• Efficacy demonstrated with extended-release formulation 5

Additional Anxiety Disorders (FDA-Approved for XR formulation)

• Social anxiety disorder: Regulatory approval obtained 5
• Panic disorder: FDA-approved indication 5

Off-Label Uses (Suggestive Evidence)

The following conditions show preliminary evidence from open-label studies, though additional randomized controlled trials are needed 4:

• Post-traumatic stress disorder 5
• Obsessive-compulsive disorder 4, 5
• Chronic pain and fibromyalgia 4
• Trichotillomania 4
• ADHD 4

Critical Safety Monitoring

Blood Pressure Monitoring

• Monitor blood pressure at doses >150 mg/day due to dose-dependent hypertension risk 2, 3
• Incidence of blood pressure elevation: 3-5% at ≤200 mg/day, 7% at 201-300 mg/day, 13% at >300 mg/day (vs. 2% with placebo) 6

Cardiac Precautions

• Prescribe cautiously in patients with cardiac disease due to reports of cardiac conduction abnormalities 2
• Seizure rate and cardiac conduction changes comparable to SSRIs 6

Discontinuation Protocol

• Never discontinue abruptly—always taper gradually 3
• Taper over 10-14 days minimum to avoid withdrawal syndrome 2
• Withdrawal syndrome is well-documented and can be severe 3

Special Population Dosing

Hepatic Impairment

• Reduce total daily dose by 50% in patients with mild to moderate hepatic impairment or cirrhosis 1
• Individual variability is high; some patients may require >50% reduction 1

Renal Impairment

• Reduce total daily dose by 25% in mild to moderate renal impairment (GFR 10-70 mL/min) 1
• Reduce total daily dose by 50% in patients undergoing hemodialysis 1

Elderly Patients

• No dose adjustment recommended based on age alone 1
• Exercise caution and use extra care when increasing doses 1

Pregnancy (Third Trimester)

• Neonates exposed late in third trimester may develop complications requiring prolonged hospitalization, respiratory support, and tube feeding 1
• Carefully weigh risks versus benefits when treating pregnant women 1

Clinical Response Timeline

• Adequate trial duration: 4-6 weeks, including titration time 2
• Early response: Some studies show superiority over placebo as early as Week 1-2, particularly at higher doses (150-200 mg/day) 6, 7
• Rapid onset potential: Demonstrated superiority as early as Day 4 in melancholic inpatients 6

Maintenance Treatment

• Acute episodes of major depressive disorder require several months or longer of sustained therapy beyond acute response 1
• Long-term efficacy demonstrated in maintenance studies at 75-225 mg/day for up to 52 weeks 1

Common Adverse Effects

The most frequent adverse effects leading to discontinuation include 6:

• Nausea (6%—most common overall but typically resolves within 1-3 weeks)
• Somnolence (3%)
• Insomnia (3%)
• Dizziness (3%)
• Other significant effects: constipation, sweating, nervousness, abnormal ejaculation 6

Therapeutic Drug Monitoring

For patients requiring therapeutic drug monitoring, steady-state plasma concentrations at standard doses 8:

• 75 mg/day: Venlafaxine 75±93 ng/mL, O-desmethylvenlafaxine 116±65 ng/mL
• 150 mg/day: Venlafaxine 109±232 ng/mL, O-desmethylvenlafaxine 186±94 ng/mL
• 225 mg/day: Venlafaxine 178±283 ng/mL, O-desmethylvenlafaxine 232±132 ng/mL
• 300 mg/day: Venlafaxine 155±109 ng/mL, O-desmethylvenlafaxine 249±121 ng/mL