Important: This is informational content only. Always consult Dr. Ambrish Singal or your psychiatrist before starting, stopping, or changing any medication.
What is Venlafaxine?
Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI). It affects both serotonin and norepinephrine systems, making it effective for depression, anxiety, and chronic pain conditions.
How It Works
At lower doses, venlafaxine primarily inhibits serotonin reuptake. At higher doses (>150mg), it also significantly inhibits norepinephrine reuptake, providing dual-action antidepressant effects.
Uses
How This Drug Starts Working
Initial improvements in 1-2 weeks, full effect 4-6 weeks. Different effects activate at different doses.
Week-by-Week Timeline
Week 1: Serotonin effects begin (similar to SSRI). May notice nausea initially. Sleep may start improving.
Week 2: If at higher dose (>150mg), norepinephrine effects add energy and alertness. Anxiety may reduce.
Week 3-4: Mood lifting. Motivation and concentration improving. Pain symptoms (if present) may reduce.
Week 5-6: Full dual-action antidepressant effect. Mood, energy, concentration all significantly better.
What Changes First?
At lower doses (<150mg): behaves like an SSRI — sleep and anxiety improve first. At higher doses (>150mg): added norepinephrine gives energy, alertness, and pain relief on top of mood improvement.
Why Does It Take Time?
Two neurotransmitter systems are being rebalanced. Serotonin effects appear at lower doses first. Norepinephrine effects only activate at higher doses, adding a second layer of therapeutic action.
Complete Dosage Guide
How to Take
Take the EXTENDED-RELEASE (XR) capsule once daily with food. Swallow whole — do NOT open, crush, or chew. Can be taken morning or evening.
Starting Dose
75mg XR once daily with food. Some doctors start at 37.5mg for the first week if you're sensitive to medications.
Dose Increases
Increase by 75mg every 4-7 days as tolerated. Key threshold: at 150mg+, norepinephrine reuptake inhibition activates (becomes a true SNRI).
Maximum Dose
Depression: 225-375mg/day. GAD: 225mg/day. Some treatment-resistant cases may use up to 375mg.
When to Take
Can be taken morning or evening. If it causes insomnia, take in the morning. If sedating, take at bedtime. Consistency is key.
If You Miss a Dose
Take as soon as remembered. If close to next dose, skip. DO NOT run out of this medication — withdrawal symptoms start within hours due to short half-life. Keep extra supply for emergencies/travel.
Food & Drink
Take WITH food to reduce nausea. XR capsule contents can be sprinkled on applesauce if swallowing is difficult (do NOT chew the beads).
How Long to Take
Long-term treatment usually recommended. If stopping: taper VERY gradually over 4+ weeks minimum. This is one of the hardest antidepressants to discontinue.
Dosage by Age Group
adult
Extended-release: Start 75mg/day. May increase by 75mg every 4 days. Maximum: 225-375mg/day.
child
Not FDA-approved for children. Sometimes used off-label in adolescents.
elderly
Start at lower doses (37.5mg). Adjust based on renal/hepatic function.
Special Populations
Pregnancy
Category C. Third-trimester exposure may cause neonatal complications. Weigh risks carefully.
Kidney Conditions
Reduce dose by 25-50% in moderate-severe renal impairment.
Liver Conditions
Reduce dose by 50% in moderate hepatic impairment.
Side Effects
Common
- Nausea
- Headache
- Dizziness
- Insomnia
- Dry mouth
- Sweating
- Sexual dysfunction
- Increased blood pressure
Serious
- Sustained hypertension (dose-related)
- Serotonin syndrome
- Suicidal ideation
- Mydriasis (risk in glaucoma)
- Discontinuation syndrome
What You Should Know
Overdose Risks
Can be dangerous in overdose. May cause seizures, cardiac conduction abnormalities, serotonin syndrome, and rhabdomyolysis. More toxic in overdose than SSRIs.
Safe Discontinuation
Taper very gradually over 4+ weeks. High risk of discontinuation syndrome including brain zaps, dizziness, irritability, nausea. Never stop abruptly.