Q: I am living in US for the last 3 years and out of practice for the last 5 years. My sister in law is having some problem with her periods. She is 36 years old and she has one daughter (8 years old), she had one miscarriage 4 years back. She gets her periods regularly but on the 4th day bleeding stops and it starts again after 5 days for next 4-5 days. Her doctor has given her tab letroze 2.5 mgs OD for 5 days starting from 3rd day of periods and then she wants to do ultrasound from 11th day for ovulation. I could not find any role of this medicine in hormonal imbalance. Could you please explain me what is the mechanism of action of this medicine in this case, or the doctor is suspecting something else?

A:You have explained about your sister in laws bleeding pattern but not the diagnosis. What was the cause of the abnormal bleeding pattern? Was an attempt made to find a cause at all? Is infertility a problem with her? Well if letrozole (an aromatase inhibitor, used in treatment for breast cancer generally) was prescribed, maybe the doctor thinks she has PCOS (Polycystic Ovarian Syndrome) Well of course the exact diagnosis and reason to give this drug can be told by the treating physician but letrozole is used sometimes in ovulation induction (FDA and the British authorities have not yet approved of this drug for ovulation induction!) but there are studies which state that it can be used in clomiphene resistant cases. It is also given sometimes in unexplained infertility. It is not yet a standard treatment for anovulation and most standard text books say that it is too early to say whether it has advantages over clomiphene or is it as safe? The ovulation induction function of the drug was discovered accidentally and is being explored as a possibility? Why did the doctor prescribe it, I think the best person to answer that is the prescribing doctor. No, I do not think the doctor is suspecting something else. Well it is a anti cancer drug but here it is being used to induce ovulation (treat infertility).