methotrexate + letrozole

Methotrexate + letrozole is a combination of two small molecule drugs used experimentally for the medical management of ectopic pregnancy, particularly tubal and cesarean scar pregnancies. Methotrexate is an antimetabolite and antifolate agent that inhibits dihydrofolate reductase, thereby blocking DNA synthesis and cell replication, especially in rapidly dividing cells such as trophoblastic tissue. Letrozole is a non-steroidal aromatase inhibitor that suppresses estrogen biosynthesis by inhibiting the enzyme aromatase (CYP19A1), reducing circulating estrogen levels. The rationale for combining these agents is to enhance efficacy in resolving ectopic pregnancies while potentially improving safety or reducing side effects compared to methotrexate alone. This combination remains under investigation; evidence from clinical trials suggests possible benefits but further studies are needed to establish its efficacy and safety profile[1][2][5][6].