What is the recommended dosing regimen for Lexapro (escitalopram) for a patient with Premenstrual Dysphoric Disorder (PMDD) symptoms?

Prescribing Lexapro for PMDD with Luteal Phase Dosing

For PMDD, prescribe escitalopram (Lexapro) 10 mg daily continuously, as SSRIs are first-line treatment and continuous dosing appears more effective than luteal-only administration for premenstrual symptoms. 1

Evidence-Based Dosing Strategy

Continuous vs. Luteal Phase Administration

• Continuous daily dosing of SSRIs is more effective than luteal phase-only dosing for reducing overall premenstrual symptoms (continuous: SMD -0.69 vs. luteal phase: SMD -0.39, P = 0.03 for subgroup difference). 1

• While luteal phase administration (last 14 days of cycle) reduces medication exposure and costs, the evidence demonstrates superior symptom control with continuous administration. 1, 2

• Escitalopram 10-20 mg/day is identified as a first-line SSRI treatment for PMDD. 3

Practical Prescription Approach

If you must write for intermittent dosing despite lower efficacy:

• Prescribe escitalopram 10 mg daily starting on day 14 of the menstrual cycle (or at symptom onset) and continuing through the first few days of menses. 4, 2

• Symptom-onset dosing (starting when symptoms begin rather than fixed day 14) has shown mixed results, with some outcome measures showing benefit and others not. 4

• The typical luteal phase regimen involves 14 days of treatment per cycle, though some patients may benefit from symptom-onset through menses dosing. 2

Dosing Specifics

• Standard dose: 10 mg daily is the established starting dose for PMDD. 3

• Maximum dose can be increased to 20 mg daily if needed for symptom control. 3

• Unlike other SSRIs (sertraline, fluoxetine, paroxetine), escitalopram does not have FDA approval specifically for PMDD, though it is supported by clinical evidence. 2

Important Clinical Considerations

Discontinuation Concerns with Intermittent Dosing

• Abrupt cessation with luteal-only dosing does not appear to cause significant withdrawal symptoms, which is reassuring for intermittent regimens. 4

• This contrasts with concerns about SSRI discontinuation syndrome seen with continuous long-term use. 4

Expected Adverse Effects

The patient should be counseled about probable side effects (all moderate-certainty evidence): 1

• Nausea (OR 3.30) - most common
• Sexual dysfunction/decreased libido (OR 2.32)
• Insomnia (OR 1.99)
• Fatigue (OR 1.52)
• Dizziness (OR 1.96)
• Dry mouth (OR 2.70)
• Asthenia/decreased energy (OR 3.28)

Response Expectations

• Approximately 67% of patients respond to SSRI treatment for PMDD. 4

• SSRIs reduce overall premenstrual symptoms with moderate effect size (SMD -0.57). 1

• Greatest improvement is seen in anger/irritability symptoms. 4

Sample Prescription Format

Escitalopram 10 mg tablets

• Sig: Take 1 tablet by mouth daily
• Quantity: 30 tablets
• Refills: 11 (for 1 year trial)

For luteal-only dosing (less preferred):

• Sig: Take 1 tablet by mouth daily starting on day 14 of menstrual cycle through day 3 of menses
• Quantity: 17 tablets per cycle × 3 cycles = 51 tablets
• Refills: 3

Clinical Pitfall to Avoid

Do not prescribe "as needed" or PRN dosing for acute symptom relief - SSRIs require consistent administration during the treatment interval to be effective, whether continuous or luteal phase. 2 The medication works through sustained serotonergic modulation, not acute symptom suppression. 5