Resuming Venlafaxine (Effexor) After 3-Week Discontinuation
After a 3-week discontinuation of venlafaxine 75mg, the patient must restart at a lower dose of 37.5mg daily for at least one week before returning to 75mg to minimize withdrawal recurrence and side effects, particularly nausea. 1
Rationale for Dose Reduction on Restart
- Venlafaxine has a very short half-life and complete drug clearance occurs within days, meaning after 3 weeks, no medication remains in the system and the patient is physiologically naive to the drug again 1
- Abrupt discontinuation of venlafaxine carries a high risk of withdrawal syndrome, which this patient likely experienced, and restarting at full dose risks severe nausea and other adverse effects 1
- The withdrawal mechanism is similar to SSRIs but of higher intensity, making venlafaxine particularly problematic when restarting 1
Recommended Restart Protocol
Week 1:
- Start venlafaxine 37.5mg once daily (or 37.5mg twice daily if using immediate-release formulation) 2, 3
- Monitor for nausea, dizziness, and somnolence, which are the most common side effects 2
Week 2 and beyond:
- Increase to 75mg daily if the patient tolerates the initial dose 2, 3
- This can be given as 37.5mg twice daily or 75mg once daily if using extended-release 4
Critical Monitoring Parameters
- Nausea is the most common adverse effect (6% discontinuation rate) but typically resolves within 1-3 weeks 2
- Blood pressure monitoring is essential, as 3-5% of patients on doses ≤200mg/day develop dose-dependent blood pressure elevation 2
- Watch for recurrence of withdrawal symptoms including somatic and psychiatric manifestations that may resemble stroke in severe cases 1
Common Pitfall to Avoid
Do not restart at the previous 75mg dose immediately. The patient's body has completely cleared the medication after 3 weeks, and restarting at full dose significantly increases the risk of intolerable nausea (the leading cause of discontinuation) and other adverse effects that could lead to treatment failure 2, 4. The gradual titration approach used in clinical trials (starting at 75mg and going up to 375mg) demonstrates that even therapeutic doses require tolerance building 2, 3.
Alternative Consideration
- If the patient experienced severe withdrawal symptoms during the 3-week gap, consider re-prescribing venlafaxine 150mg per day initially, as this dose was effective in rapidly resolving severe withdrawal syndrome in documented cases 1
- However, this higher restart dose should only be used if withdrawal symptoms are currently present and severe; otherwise, the standard 37.5mg restart is preferred 1