Hi, I Am A 50 Yr Old Female With Asthma.

Hi, I am a 50 yr old female with asthma. My lung specialist has done blood work which came back that I am allergic to something that really messes up my breathing. He's recommended a newer medicine to treat this with. I believe it starts with an "N" but I can't be sure. I'm looking for the name of the medicine, injection every 1-3 months, and side effects. thank you in advance for your help.