Venlafaxine (Effexor): Uses, Dosage, Side Effects, and What to Expect

Venlafaxine (brand name: Effexor XR) is a serotonin-norepinephrine reuptake inhibitor (snri). Venlafaxine inhibits reuptake of both serotonin and norepinephrine in a dose-dependent manner. At lower doses (75 mg), it acts primarily as an SSRI. At moderate doses (150 mg), norepinephrine reuptake inhibition becomes significant. At higher doses (225-375 mg), mild dopamine reuptake inhibition may contribute. This dose-dependent profile allows clinicians to titrate to target specific neurotransmitter systems.

• Major Depressive Disorder (MDD)
• Generalized Anxiety Disorder (GAD)
• Social Anxiety Disorder
• Panic Disorder

Common off-label uses:

• Neuropathic pain
• Migraine prophylaxis
• ADHD (adjunctive)
• Hot flashes
• PTSD
• OCD (treatment-resistant)

Extended-release (XR) formulation preferred. Start at 37.5-75 mg once daily with food. Increase by 75 mg every 4-7 days. Therapeutic range: 75-225 mg/day. Maximum: 375 mg/day for severe depression. Renal/hepatic impairment requires dose reduction.

Anxiety improvement may begin within 1-2 weeks. Full antidepressant effect in 4-6 weeks.

• Nausea (most common, often resolves in 1-2 weeks)
• Headache
• Dizziness
• Insomnia or somnolence
• Dry mouth
• Constipation
• Sexual dysfunction
• Increased sweating
• Elevated blood pressure (dose-dependent)

• Sustained hypertension (monitor blood pressure regularly, especially above 150 mg)
• Serotonin syndrome
• Suicidal ideation in young adults
• Severe discontinuation syndrome
• Hepatotoxicity (rare)
• Angle-closure glaucoma

Contraindicated with MAOIs. Caution with other serotonergic drugs. Metabolized primarily by CYP2D6; CYP2D6 poor metabolizers may have higher levels. Less CYP450 inhibition than fluoxetine or paroxetine.

FDA Pregnancy Category C. Neonatal discontinuation syndrome may occur. Third-trimester exposure associated with transient neonatal symptoms in ~30% of cases.

Venlafaxine has one of the most notable discontinuation syndromes of any antidepressant. Taper very gradually — 10-25% dose reduction every 2-4 weeks. Symptoms include electric shock sensations ('brain zaps'), dizziness, nausea, irritability, and vivid dreams. Some patients require months-long tapers.