Mixture of deuterium-enriched compounds of formula or pharmaceutically acceptable salt thereof: wherein R1-R11 are independently selected from and and the abundance of deuterium in R1-R11 is at least. Letrozole, an antineoplastic nonsteroidal aromatase inhibitor. Patients on tamoxifen had significantly more thromboembolic events, hot flushes, vaginal bleeding, night sweats, and endometrial events. These genes, selected on statistical rationale, are known to kopen letrozole pillen be related to the estrogen and progesterone biology, adding strong pathological rationale to the selection process. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. However, must again emphasize that such complication is extremely rare.