Restarting Paroxetine After 5-Day Interruption
Do not restart at 40 mg after a 5-day gap—begin at 10-20 mg and titrate gradually over 1-3 weeks back to 40 mg to minimize discontinuation syndrome rebound and adverse effects. 1, 2
Rationale for Dose Reduction
After missing 5 days of paroxetine, the patient has likely experienced partial drug washout and may have developed discontinuation syndrome symptoms (dizziness, anxiety, irritability, sensory disturbances). 1 Restarting abruptly at the full 40 mg dose significantly increases the risk of:
- Behavioral activation/agitation within 24-48 hours, particularly in patients with anxiety and PTSD 1, 2
- Severe nausea and other gastrointestinal side effects that led to higher discontinuation rates at higher doses 3
- Exacerbation of anxiety symptoms due to acute serotonergic surge 1, 2
Recommended Restart Protocol
Week 1: Start at 10 mg daily (or 20 mg if previously well-tolerated at 40 mg for extended periods) 4, 5
Week 2-3: Increase by 10 mg increments at weekly intervals, monitoring for adverse effects 4, 3
Week 3-4: Reach target dose of 40 mg once tolerability is confirmed 4, 3
This gradual approach is particularly critical in patients with anxiety disorders and PTSD, where slow titration significantly improves treatment completion rates (80% vs 23% dropout with rapid titration in anxious patients). 5
Special Considerations for This Patient Population
Diabetes monitoring: Ensure blood glucose stability during medication restart, as SSRIs can affect glycemic control 1
Anxiety/PTSD symptoms: The American Academy of Child and Adolescent Psychiatry recommends starting with subtherapeutic "test doses" when anxiety is prominent to minimize initial agitation 1, 2
Age considerations: If the patient is elderly (>60 years), start at 10 mg and titrate even more slowly (2.5-5 mg increments every 3-7 days) to minimize adverse effects 5
Monitoring During Restart Phase
- Assess weekly for discontinuation syndrome resolution (dizziness, paresthesias, anxiety) 1
- Monitor for behavioral activation in first 24-48 hours after each dose increase 1, 2
- Evaluate anxiety and PTSD symptoms using standardized scales every 2-4 weeks 1
- Watch for suicidality risk during the first 1-2 months, as risk is greatest during treatment initiation and changes 1
Common Pitfall to Avoid
Do not restart at full dose assuming "the patient was already on 40 mg before"—the 5-day gap represents a treatment interruption requiring re-titration. Paroxetine has a relatively short half-life (approximately 21 hours), meaning drug levels have substantially declined after 5 days, and the patient's serotonin receptors have begun readjusting. 1, 4 Abrupt reinitiation at 40 mg treats this as continuation therapy when it functionally represents treatment re-initiation. 5, 3