Taking low-dose Prozac (fluoxetine) for a few days during the premenstrual period shows promise in preventing the negative and emotional symptoms associated with PMS (premenstrual syndrome), neuroscientists at the University of Birmingham, England have revealed. PMS affects millions of women globally.
The researchers say they have identified an organic cause for PMS. Dr. Thelma Lovick and team have demonstrated in animal (rats) experiments that PMS-like symptoms can be triggered when the secretion of a female sex hormone changes towards the end of the menstrual cycle.
The scientists believe that the negative physical and emotional symptoms of PMS could be avoided if women with PMS were to take fluoxetine in low doses for just a few days during their menstrual period.
Dr. Lovick said:
All that would be needed for countless women to benefit from what could be a simple and accessible treatment, involving a drug that is already in widespread use, is clinical tests to refine it and identify the optimal dosing strategy.
The investigators say they now seek a clinical partner who could fund a clinical trial to confirm their findings.
The researchers found out that ALLO (allopregnanolone), a steroid substance, a breakdown substance of progesterone, usually inhibits activity in the brain circuits that control emotion. Progesterone is a female sex hormone. Symptoms of PMS, including irritability, aggression and anxiety emerge when levels of ALLO drop and this inhibition is reduced, as they do during the menstrual period.
Dr. Lovick explained:
ALLO can alter the activity of nerve cells, thus it is described as a neuroactive steroid. It enhances the activity of GABA, one of the brain's inhibitory neurotransmitter chemicals, and in those parts of the brain that process emotional responses ALLO normally produces calming effects. However, when brain levels of progesterone, and hence ALLO, fall sharply during the late premenstrual period the natural inhibition is effectively turned off.
As a consequence, these brain circuits become more excitable, leaving the individual more responsive to stress, which is often manifested behaviourally as anxiety and aggressive behaviour.
If the drop in ALLO levels could be decreased gradually at the end of the menstrual cycle, PMS symptoms should not develop, if the sharp fall in ALLO levels is what causes these brain changes, Lovick hypothesized.
The researchers consequently devised an approached called "neuroactive steroid replacement treatment", which in animal experiments completely prevented the development of premenstrual symptoms.
Dr. Lovick said:
We knew that the widely used anti-anxiety drug fluoxetine (Prozac) could raise levels of ALLO when taken for short periods. This effect happened quickly and occurred in response to a very low dose of fluoxetine. We thought that if dosing with fluoxetine was carefully timed to boost brain ALLO levels just when they were due to fall sharply at the end of the cycle, the normal trigger for the development of premenstrual syndrome would be absent.
Only a very low dose is required, the scientists say, for effective results - approximately one tenth of a typical fluoxetine prescription dose.
The neurologists wrote:
'Excitingly, fluoxetine completely prevented the development of the signs of anxiety and increased pain and sensitivity normally shown by female rats in late dioestrus, their version of the premenstrual period. Moreover, it completely changed the way in which the brain circuits responded to anxiety-inducing stress.
They were also able to replicate the effects of fluoxetine using a synthetic version of ALLO.
Dr Lovick concluded:
The time is right for a controlled clinical trial in women. The solution to PMS could be as simple as taking a pill for a few days towards the ends of your menstrual cycle.
What is Premenstrual Syndrome (PMS) or Premenstrual Tension (PMT)?PMT or PMS is a collection of emotional, psychological and physical symptoms which are linked to a woman's menstrual cycle. Experts say that about four-fifths of all women of child-bearing age have some PMS symptoms. Clinicians tend to refer to PMS only when they are sufficiently severe to interfere with some aspects of a woman's life.
The following symptoms may be felt by some women on the days leading up to her period - symptoms of premenstrual syndrome:
- Abdominal cramps
- Binge eating
- Breast tenderness or swelling
- Feeling generally emotional or troubled
- Headache (include migraine)
- Lack of concentration
- Pains, especially backache
- Slight weight gain
The following factors may increase the chances of PMS:
- High caffeine consumption
- Increasing age
- A history of depression
- A family history of PMS
- Allergies, especially to nuts, grass, and trees
- Low levels of some vitamins and minerals, especially magnesium, calcium, manganese, and vitamin E. A diet rich in calcium and vitamin D may lower the risk of developing premenstrual sindrome, a study found.
Written by Christian Nordqvist