What is the recommended dose of Effexor (venlafaxine) for an adult patient with anxiety?

Effexor (Venlafaxine) Dosing for Anxiety in Adults

For adult patients with anxiety disorders, start venlafaxine at 75 mg/day and titrate to an effective dose of 150-225 mg/day, as this range has demonstrated optimal efficacy for anxiety symptoms. 1, 2

Initial Dosing

• Start with 75 mg/day administered in two or three divided doses with food (for immediate-release formulation) 1
• For extended-release (XR) formulation, use 75 mg once daily, which permits convenient single-dose administration due to its long elimination half-life 3, 4
• The 75 mg starting dose allows assessment of tolerability before escalation 1

Therapeutic Dose Range

• Target dose: 150-225 mg/day for optimal anxiety control 2, 5
• This therapeutic range typically requires 2-4 weeks of titration to reach 2
• Dose-related improvements in anxiety symptoms are evident, with higher doses (150-200 mg/day) showing earlier onset of clinical improvement (as early as 1-2 weeks) 5, 6

Dose Titration Protocol

• Increase in increments of up to 75 mg/day at intervals of no less than 4 days 1
• If partial response at 150 mg/day after 4-6 weeks, increase to 225 mg/day 2
• Maximum dose is 375 mg/day for severe or treatment-resistant cases, though outpatient anxiety typically responds to ≤225 mg/day 1, 7

Monitoring Requirements

• Blood pressure and pulse at baseline and during treatment, as venlafaxine causes dose-dependent increases in blood pressure 3, 4
• Height and weight monitoring 4
• Watch for behavioral activation, agitation, hypomania, or suicidal thinking (particularly in patients ≤24 years old), as venlafaxine may carry greater suicide risk than other SNRIs 3, 4
• Monitor for serotonin syndrome if patient takes other serotonergic medications 2

Special Populations

Renal Impairment

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

Hepatic Impairment

• Reduce total daily dose by 50% for mild-to-moderate hepatic impairment 1
• May require >50% reduction in cirrhotic patients due to individual variability 1

Elderly Patients

• No routine dose adjustment required based on age alone 1
• Exercise caution and use slower titration when increasing doses 1

Treatment Duration and Response Assessment

• Allow 4-6 weeks at therapeutic dose (150-225 mg/day) before assessing response 2
• If <30% reduction in anxiety symptoms after adequate trial at 225 mg/day, switch to alternative first-line medication (SSRI or duloxetine) 2
• Do not extend trials beyond 6-12 weeks if inadequate response, as 38% of patients do not respond even with prolonged treatment 2

Discontinuation Protocol

• Never stop abruptly due to high risk of discontinuation syndrome 3, 4
• Taper gradually over 10-14 days minimum to minimize withdrawal symptoms 4
• Use cross-tapering if switching to another medication 2
• The 37.5 mg/day dose serves as a tapering dose, not a therapeutic starting dose 4

Common Adverse Effects

• Nausea, dizziness, somnolence, insomnia, dry mouth, and asthenia are most common 3, 5
• Diaphoresis, abdominal discomfort, decreased appetite, and weight loss may occur 3
• Discontinuation for adverse events occurs in approximately 11% of patients 6

Clinical Pearls

• Venlafaxine XR demonstrates efficacy specifically for panic disorder, generalized anxiety disorder, and anxiety symptoms accompanying depression 8, 6
• Dose-related response is evident, with 150-200 mg/day showing superior early response compared to 75 mg/day 5
• Consider combining with cognitive behavioral therapy for superior efficacy compared to medication alone 2