Volume 4 Issue 11 Nov 2014
Typical and atypical antipsychotic drugs are mainstay of treatment for schizophrenia, and also used in bipolar disorder, and depression. Most of the antipsychotics (except few atypical ones) produce menstrual disturbances. To understand its mechanism a clear understanding of the functioning of hypothalamic ovarian axis is a must. In humans, GnRH neurons in the hypothalamus releases gonadotropin releasing hormone (GnRH) in a pulsatile manner. GnRH travels via hypothalamic-hypophyseal portal circulation to reach anterior pituitary, where it leads to synthesis and secretion of FSH and LH. FSH and LH in turn travel through systemic circulation to the ovaries, where they lead to steroid hormone production as well as ovulation. Regular ovulation is a pre requisite for normal cyclical menstruation. Severe suppression of H-P-O axis would ultimately lead to amenorrhea with low estrogen state.
How do antipsychotic drugs cause menstrual disorders?
The implicated antipsychotic drugs disrupt the H-P-O axis indirectly by elevating serum prolactin levels which directly suppress the pulsatile release of GnRH and hence the reproductive axis. Prolactin is the only hormone produced by anterior pituitary which is under inhibitory control of hypothalamus exerted via dopamine. Conventional antipsychotics (prolactin elevating) and some atypical antipsychotics inhibit the action of dopamine on the prolactin secreting cells of pituitary. A multitude of menstrual disturbances can be seen e.g, frequent menstruation, heavy menstruation or more commonly, infrequent and scanty menstruation. This reflects increasing suppression of GnRH pulsatile release. Further restraining of pulsatile GnRH secretion leads to deficiency of FSH and LH in amounts, which is not adequate to induce a sufficient steroid hormone production by the ovaries. So not just ovulation is disrupted, but estrogen and possibly testosterone production becomes extremely low.
How to manage hyperprolactinemia and menstrual disorder?
Switching the treatment to prolactin sparing drugs if feasible or adding estrogen replacement therapy (add back) such as oral contraceptive pills would certainly help. Dopamine agonists can be used with caution as they may aggravate acute psychotic episodes.
Department of Obstetrics & Gynecology, AIIMS Jodhpur
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