Injection meds for iui?

This will be my fourth <a href="https://glowing.com/glow-fertility-program">iui</a> and my dr said we will use a little more agressive med this time... she said it was injections.. i did 3 rounds of letrozole with trigger... and no luck.. now does anyone know what these meds are and when do use in the cycle? Thanks for replying 😊