What Should I Know About Fluoxetine and Premenstrual Syndrome?

Patricia (Pat) A. Camillo, PhD, RN, APRN-BC


September 09, 2005


What are the latest options for treating irritability in women with 3-5 days of premenstrual syndrome (PMS) monthly? Is fluoxetine useful if taken only 1 week per month?

Response from Patricia (Pat) A. Camillo, PhD, RN, APRN-BC

Treatment of PMS is complicated because there is little agreement regarding its definition.[1] Some experts view PMS as a mood disorder on the low end of a continuum, with premenstrual dysphoric disorder (PMDD) at the opposite end. Others define both as one and the same syndrome. This lack of consensus was evident in an FDA Advisory Committee Panel Discussion in November 1999.[2] The agenda for this meeting was focused on the efficacy of fluoxetine (Prozac) in managing these symptoms. Members concluded that fluoxetine could be offered to women who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM IV) criteria for PMDD.[3] This is a much more severe form of premenstrual symptomatology that includes significant mood alterations interfering with a woman's ability to engage in everyday activities and relationships.

The recommended dose of fluoxetine for PMDD is 20 mg/day continuously or intermittently. "Intermittently" is defined as "starting a daily dose 14 days prior to the anticipated onset of menstruation through the first full day of menses."[4] This is repeated with each cycle. There are limited small-scale studies that have used this dosing regimen. There are no studies supporting the use of this drug for only 1 week.

Although many women may believe that they are only getting a drug effect during the time they are actually taking fluoxetine, the half life of the active metabolite is 14 days. So, in reality, the "intermittent" regimen is closer to a chronic dosing schedule. In fact, prior to taking a monoamine oxidase inhibitor (a drug that can cause serious, life-threatening reactions when used with fluoxetine), women are encouraged to wait at least 5 weeks after stopping Serafem (the trade name for fluoxetine used for PMDD).

PMDD is a serious mood disorder, and there are certainly studies to support treatment with continuous fluoxetine. However, with specific approval for use with PMDD, it is possible that increasing numbers of female adolescents will be prescribed this drug. Studies submitted to the FDA excluded women under age 18 years as well as women who were using oral contraceptives. There has been growing concern regarding the risks for suicide in this younger population using this class of drugs. PMDD can often mimic other mental health conditions such as rapid cycling mood disorders that are more common in this age group. Use of an antidepressant can trigger a manic state in a previously undiagnosed young woman.

Prior to initiating drug therapy, 2 or 3 months of prospective symptom charting would help to fine tune the diagnosis of PMS/PMDD. If the criteria for PMDD are not met, lifestyle changes should be considered for the management of PMS. These include use of calcium supplements, a complex carbohydrate diet, relaxation techniques, and aerobic exercise.[5] For some women, use of an oral contraceptive, such as drospirenone and ethinyl estradiol (Yasmin)[6] has been successful in suppressing the hormonal fluctuations that appear to trigger the neuroendocrine instability related to these disorders.

Without doubt, the diagnosis and management of PMS and PMDD is an evolving science that requires complex clinical decision making and follow up care. The approval of SSRIs, including fluoxetine and now sertraline (Zoloft),[7] has added another option that requires careful consideration.


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