Possible Interaction: Progesterone and Letrozole

“ Progesterone concentrations and oestradiol concentrations were significantly lower in the letrozole group than in the CC group on the day of LH peak.”

“In patients undergoing administration with Letrozole , those taking progesterone had thinner endometrium and lower peak endometrial-thickness/baseline endometrial-thickness.”

“Even with a sensitivity limit below 1 pM as used in the second study, most patients experienced plasma estradiol suppression below the …, underlining the invalid method used by Rossi et al. Further, the authors report a statistically significant increase in plasma levels of progesterone during … letrozole as compared … tamoxifen.”

“This study demonstrates that the addition of 5 mg of letrozole in the luteal phase of stimulated donor IVF cycles significantly alters the oestradiol levels on days 4, 7 and 10 after HCG administration for final oocyte maturation.”

“Corpus luteum diameter profiles and progesterone production were not affected by day-group although reduced luteal lifespan after letrozole treatment was observed and requires further investigation.”

“Administration of 0.1 or ….5 mg/kg of LTZ on days 5–… of the luteal phase caused a profound drop in the levels of E2 in all animals, whereas administration of ICI … 0.2 mg/kg on days 4–6 of the luteal phase had the opposite effect.”