Discovered by Dr. Alexander Fleming, the medical breakthrough of Penicillin was the first whole type of drugs that has saved and saves millions of lives. We call these type of drugs what ?

Penicillin is an antibiotic.

Explanation:

     Benzathine penicillin, also called benzathine benzylpenicillin or benzathine penicillin G, is an antibiotic in the penicillin family, which is administered intramuscularly and serves to fight bacterial infections, such as syphilis or bacterial tonsillitis.