Talk to Urologist on Low Sperm Count And Motility

Hi, there , i was diagnosed with low sperm count and motility , dr recommend for ultrasound of testicles and after ultrasound results dr told me i have small testis compare to average testis, my dr prescribed me letrozole 2.5 mg twice a day for 3 months with some other supplements, i wana ask is it safe to take letrozole 2.5 mg twice a day, i did some research and reading and find out letrozole 2.5 mg twice a day is too much, so please help me out