Prozac Dosing for Premenstrual Dysphoric Disorder (PMDD)
For PMDD treatment, fluoxetine (Prozac) 20 mg daily is the recommended dose, administered either continuously throughout the menstrual cycle or intermittently during the luteal phase (14 days before expected menses through the first day of bleeding). 1
Dosing Regimens
Continuous Daily Dosing
- 20 mg daily throughout the entire menstrual cycle is effective for both mood and physical symptoms of PMDD 1, 2
- This regimen demonstrated significant improvement in luteal phase symptom scores compared to placebo (P = 0.005) 1
- Treatment effects are evident by the first treatment cycle and remain superior to placebo throughout treatment 1
Intermittent Luteal Phase Dosing
- 20 mg daily starting 14 days before expected menses through the first full day of bleeding is equally effective 1, 2
- This approach minimizes total medication exposure while maintaining efficacy 2
- Particularly effective for emotional symptoms, with additional benefit for physical symptoms including breast tenderness (P < 0.001), bloating (P = 0.001), and joint/muscle pain (P = 0.037) 1
Alternative Dosing Options
- Fluoxetine 10 mg daily (luteal phase) showed improvement but did not reach statistical significance compared to placebo (P = 0.100) and is therefore not recommended as first-line 1
- Enteric-coated fluoxetine 90 mg given twice during the luteal phase (at 14 days and 7 days before expected menses) demonstrated efficacy but requires specialized formulation 3
- The 60 mg daily dose showed no additional benefit over 20 mg daily but significantly increased side effects (P < 0.001) 4
Clinical Considerations
Efficacy Profile
- Response rates range from 50-78.6% with continuous treatment 5
- Both mood-related and physical symptoms improve with 20 mg dosing 1
- Psychosocial functioning and quality of life measures show significant improvement 3
Tolerability
- The 20 mg dose is well-tolerated with discontinuation rates due to adverse events not differing from placebo (P = 0.316) 1
- Common side effects are generally mild and transient 2
- Discontinuation effects have not been reported with intermittent dosing regimens 2
Duration of Treatment
- Treatment effects are sustained for at least six consecutive menstrual cycles 5
- Efficacy is maintained with both continuous and intermittent protocols over this timeframe 5
Practical Algorithm
Start with fluoxetine 20 mg daily using either:
- Continuous dosing (every day) if the patient prefers simplicity or has symptoms extending beyond the luteal phase
- Luteal phase dosing (days 14 before menses through first day of bleeding) if the patient prefers minimal medication exposure and has clearly defined luteal-phase-only symptoms
Do not increase to 60 mg as this provides no additional benefit but increases side effects significantly 4
Do not use 10 mg as the primary dose, as it lacks consistent efficacy compared to placebo 1