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venlafaxine

Adjunctive therapy

Brand: Effexor XR

Published 2025-09-28 · Last reviewed 2025-10-05 · 4 references

Content sourced from FDA labeling (DailyMed) and peer-reviewed literature.

Print sheet Review evidence

At a glance

Class: Adjunctive therapy·Typical dose: Initiate XR 37.5 mg once daily with food for 4–7 days, then 75 mg/day; increase by 75 mg increments at ≥7-day intervals up to 225 mg/day (300 mg off-label).·Half-life: Single-dose mean 5 h; Single-dose range 4–6 h; Steady-state mean 11 h; Steady-state range 9–13 h·LAI available: No

Class: Adjunctive therapy
Typical dose: Initiate XR 37.5 mg once daily with food for 4–7 days, then 75 mg/day; increase by 75 mg increments at ≥7-day intervals up to 225 mg/day (300 mg off-label).
Half-life: Single-dose mean 5 h; Single-dose range 4–6 h; Steady-state mean 11 h; Steady-state range 9–13 h
LAI available: No

Quick answers

What is venlafaxine?: Venlafaxine (Effexor XR) is an SNRI with dose-dependent norepinephrine activity, commonly selected for comorbid anxiety or pain syndromes in serious mental illness.
What is Effexor XR?: Effexor XR is a brand name for venlafaxine.
What is Effexor XR (venlafaxine) used for?: Label indications include: Major depressive disorder; generalized anxiety disorder; social anxiety disorder; panic disorder.
What drug class is Effexor XR (venlafaxine)?: SNRI Antidepressant.
What is the mechanism of action of Effexor XR (venlafaxine)?: Serotonin-norepinephrine reuptake inhibitor (SNRI).
What strengths does Effexor XR (venlafaxine) come in?: Extended-release capsules 37.5 mg, 75 mg, 150 mg; ER tablets 37.5–225 mg; legacy IR tablets 25–100 mg.

General information

Venlafaxine (Effexor XR) is an SNRI with dose-dependent norepinephrine activity, commonly selected for comorbid anxiety or pain syndromes in serious mental illness.

Extended-release formulations dominate due to once-daily dosing and improved tolerability compared with immediate-release tablets.

The compare view and the venlafaxine evidence feed can help compare activation, blood pressure, and sexual side effects alongside condition hubs (e.g., bipolar disorder) when planning augmentation or cross-taper strategies.

The highest-yield practical issues are blood pressure monitoring and discontinuation planning; missed doses and rapid tapers can trigger significant withdrawal symptoms.

Care transitions are a common source of withdrawal risk; verifying formulation, dose, and refill continuity can prevent abrupt interruption.

U.S. approvals

Major depressive disorder (1993)
Generalized anxiety disorder (1999)
Social anxiety disorder (2003)
Panic disorder (2005)

Formulations & strengths

Extended-release capsules 37.5 mg, 75 mg, 150 mg; ER tablets 37.5–225 mg; legacy IR tablets 25–100 mg.

Generic availability

Generic ER capsules and tablets widely available; brand Effexor XR still marketed.

Monitor blood pressure and withdrawal risk; counsel on adherence and gradual tapering to avoid discontinuation syndrome.

View labelExact

Mechanism of action

Refer to the Glossary entry on Neurotransmitters for background on receptor systems involved in serious mental illness.

Serotonin reuptake inhibition across clinical doses; norepinephrine reuptake inhibition emerges ≥150 mg/day; very weak dopamine reuptake inhibition at high doses.

SERT and NET inhibitor with minimal muscarinic/histamine/α1 affinity.

Metabolism & pharmacokinetics

XR Tmax 5.5–9 h; protein binding ~27%.
Metabolized via CYP2D6 (major) and CYP3A4 to active O-desmethylvenlafaxine.
Half-life ~11 h (XR); active metabolite ~10–13 h; eliminated renally (87% as parent/metabolites).
Renal and hepatic impairment both increase exposure; dose reductions and slower titration are common when tolerability limits continuation.

Dosing & administration

Initiate XR 37.5 mg once daily with food for 4–7 days, then 75 mg/day; increase by 75 mg increments at ≥7-day intervals up to 225 mg/day (300 mg off-label).
Reduce total daily dose 25–50% in renal or hepatic impairment.
Taper gradually over several weeks to prevent discontinuation symptoms.
If discontinuation symptoms emerge during tapering, slower dose reductions over longer intervals are often better tolerated than larger step-downs.

Monitoring & labs

Blood pressure and heart rate at baseline and after titration, with extra attention at higher doses.
Discontinuation symptoms during missed doses or tapering; plan refill timing and taper steps proactively.
Sodium in older adults or diuretic users if symptoms suggest hyponatremia (confusion, fatigue, falls).
Mood elevation or agitation in bipolar-spectrum illness; coordinate prevention plans via the bipolar disorder hub.
Medication reconciliation to avoid serotonergic combinations and to plan MAOI washouts when regimens change.

Venlafaxine has a short half-life; adherence and taper planning often matter more than the exact starting dose for day-to-day tolerability. Blood pressure checks and predictable tapers prevent avoidable problems during dose changes and missed doses in many patients overall too.

Adverse effects

FDA boxed warnings

Antidepressants increase suicidality risk in children, adolescents, and young adults; monitor closely.

Common side effects (≥10%)

Nausea: Most common early effect; taking with food or at bedtime may help.
Insomnia or somnolence: Mixed activating/sedating profile—adjust dosing time accordingly.
Sweating: Often dose-related; monitor at higher doses.
Blood pressure elevation: Check BP at baseline and after titrations, especially ≥225 mg/day.
Sexual dysfunction: Discuss proactively to support adherence.

Other notable effects

Discontinuation syndrome (dizziness, paresthesia) can be severe—plan slow tapers.
Hyponatremia, increased cholesterol, and angle-closure glaucoma reported rarely.
Serotonin syndrome possible with concomitant serotonergic agents.
Mania/hypomania can emerge in bipolar spectrum disorders—screen before initiation and coordinate mood stabilizer coverage via the bipolar disorder hub.

Interactions

CYP2D6/3A4 substrates—strong inhibitors (fluoxetine, paroxetine, ritonavir) can raise concentrations; monitor for hypertension or adverse effects.
Contraindicated with MAOIs; observe 7-day washout before starting an MAOI.
Additive bleeding risk with NSAIDs, antiplatelets, anticoagulants.
Use caution with other serotonergic agents (SSRIs, triptans, tramadol, linezolid, St. John’s wort) that can raise serotonin-syndrome risk.

Other useful information

Encourage once-daily dosing with food to reduce GI upset.
Consider desvenlafaxine if CYP2D6 interactions limit dosing.
Set expectations that benefit builds over weeks; early side effects are often earlier than mood improvement and may improve with supportive care.

References

Related hubs:SMI toolkit·Support resources