SNRIs · Psychiatry
Venlafaxine
Effexor XR®(brand names vary by market)
An SNRI that is mostly an SSRI at low dose and finds its noradrenaline at higher doses.
Also: capsule
Mechanism
Serotonin and (dose-dependently) noradrenaline reuptake inhibition; the dual mechanism arrives as the dose climbs.
Open the interactive pathwayIndications
- Major depressive disorder
- Generalized anxiety disorder
- Panic disorder
Formulations
Dosing concepts
Blood pressure
Noradrenergic activity raises blood pressure dose-dependently; check it before and after titration.
Discontinuation
Short half-life makes venlafaxine's discontinuation syndrome among the worst of the antidepressants; taper slowly and never end on alternate-day dosing of the XR form.
Concepts, not prescribing instructions. Practice numbers live in current references and local protocols.
Pharmacokinetics
- Bioavailability
- ~45%
- Half-life
- 5 h (parent), 11 h (active metabolite)
- Elimination
- hepatic: CYP2D6 to the equally active desvenlafaxine
Adverse effects
- Nausea (early)common
- Hypertension, dose-relatedcommon & serious
- Sweating, insomniacommon
- Discontinuation syndromecommon
- Serotonin syndrome with serotonergic partnersserious
Contraindications & precautions
Contraindications
- MAO inhibitor within 14 days
Precautions
- Uncontrolled hypertension
- Arrhythmia history
Interactions
Monitoring
Blood pressure
The class-defining check SSRIs do not need · Baseline and after dose increases
Mood and safety
Effectiveness
Counselling points
- Take the XR capsule once daily with food.
- Missed doses can cause dizziness and 'zaps' within a day or two. Consistency matters more than with most medications.
Clinical pearls
- If a patient reports withdrawal symptoms the same evening a dose is missed, think venlafaxine before anything else.
References & review
- Venlafaxine product monograph (consult the current version for your market) (monograph)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed. (reference-work)
Last reviewed 2026-08-15 · jurisdiction: global · drug information changes; verify against current references before practice use.