Citalopram in PMS patients with prior SSRI treatment failure: A preliminary study

Objectives: Evidence shows that the selective serotonin reuptake inhibitors (SSRIs) effectively reduce the symptoms of severe premenstrual syndrome (PMS). A placebo-controlled study of citalopram, the most selective SSRI, demonstrated that half-cycle dosing (luteal phase) was effective for DSM-IV-defined premenstrual dysphoric disorder (PMDD), a severe form of PMS. This study examined the effectiveness of half-cycle dosing of citalopram in PMS patients who did not respond to previous SSRI treatment. Methods: Seventeen women with no improvement in symptoms after two menstrual cycles on an SSRI were given open-label citalopram (20-40 mg/day). Eleven subjects received half-cycle dosing, and 6 subjects received full-cycle dosing. Scores on the 17-item daily symptom report (DSR) and on each of five DSR symptom clusters were used to measure citalopram efficacy. Results: Total premenstrual DSR scores were significantly improved (p < 0.001) in both half-cycle and full-cycle dosing groups. The half-cycle group reported lower DSR scores throughout treatment compared with the full-cycle group, but the difference did not reach statistical significance in this small sample. All DSR factor scores (mood, behavioral, pain, physical symptoms, and appetite) significantly improved. Clinical improvement (≥50% decrease from baseline DSR) was reported by 76% of the subjects overall. Forty-one percent of the subjects experienced symptom remission, defined as a decrease in symptoms to postmenstrual levels. Conclusions: These results from a small number of subjects with open-label treatment must be viewed as preliminary but suggest that citalopram treatment is effective for PMS patients who failed previous SSRI treatment.