SNRI·Psychiatry - Antidepressants

Venlafaxine XR

Major Depressive Disorder, GAD, Panic Disorder

PBSSNRIEfexor-XR, Elaxine PR37.5 mgS4+1

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At a glance

Max Dose

225 mg/day

Half-life

5 h (Act: 11h)

Caution: Hypertension

DOSE-DEP

High risk: Withdrawal

SEVERE

Cautions

Avoid / Cautions

Concurrent MAOI use (Fatal Serotonin Syndrome), uncontrolled severe hypertension. Pregnancy Category B2. Can cause severe withdrawal symptoms in the neonate if used until term.

Where it stands

Rapid Summary

Overview

Serotonin-Noradrenaline Reuptake Inhibitor (SNRI). Highly effective for severe/refractory depression. The noradrenaline blockade kicks in at higher doses, providing an activating, energy-boosting effect.

Clinical Focus

Missing even a single dose triggers a horrifying withdrawal syndrome ('brain zaps', severe vertigo, flu-like crash).

Bottom Line

Venlafaxine XR is a potent SNRI for depression, GAD, and neuropathic pain, but causes dose-dependent hypertension requiring BP monitoring and has a severe discontinuation syndrome if stopped abruptly.

Formulation & Access

Brand Names

Efexor-XR, Elaxine PR

Oral Routes

Do not crush

Extended Release Capsules (37.5 mg, 75 mg, 150 mg). Do not crush. Patient may see intact ghost capsule in stool.

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Major Depressive Disorder, GAD, Panic Disorder.

Clinical Place

Second-line after SSRI failure, or first-line for severe melancholic, low-energy depression.

Quick reference

Class & Role

SNRI — Serotonin-Noradrenaline Reuptake Inhibitor (SNRI).

Route / Formulation

Extended Release Capsules (37.5 mg, 75 mg, 150 mg). Do not crush. Patient may see intact ghost capsule in stool. (Efexor-XR, Elaxine PR)

Usual Dose & Max

Start PO 75 mg OD (XR capsule). Titrate by 75 mg increments every 2-4 weeks. Max 225 mg/day.

Key Indication Doses

Depression / GAD / Panic: Start PO 75 mg OD (XR capsule). Titrate by 75 mg increments every 2-4 weeks. Max 225 mg/day. Severe Anxiety / Frail: Start PO 37.5 mg OD (XR capsule) for the first week to blunt intense initial anxiety/nausea.

Best Uses

Key Risks

Neurological: Discontinuation syndrome ('Brain zaps', dizziness, sensory disturbances, crying spells). HIGH — Insomnia, severe sweating, tremor. Cardiovascular: Dose-dependent hypertension and tachycardia (due to noradrenaline excess). Gastrointestinal: Nausea (severe upon initiation).

Key Interactions

MAOIs, Tramadol, St John's Wort. Extreme risk of Serotonin Syndrome. NSAIDs (Bleeding risk).

Monitoring

Baseline and routine BP and HR checks. If a patient develops hypertension > 150/90, reduce the dose or cease. Routine U&E (sodium) for SIADH risk.

Clinical Pearl

If you prescribe 75mg of Venlafaxine, you are effectively just prescribing a highly toxic, hard-to-stop SSRI. You MUST push the dose to 150mg or 225mg to actually unlock the noradrenaline (SNRI) benefits.

Access

Efexor-XR, Elaxine PR37.5 mg

Brand: Efexor-XR, Elaxine PR
Formulation: Extended Release Capsules (37.5 mg, 75 mg, 150 mg). Do not crush. Patient may see intact ghost capsule in stool.

From this page

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