Benzylpenicillin of penicillin allergy. Use during pregnancy is generally safe. It is in the penicillin and β-lactam class of medications. Benzylpenicillin was discovered in 1929 by Alexander Fleming and came into commercial use in 1942. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.24–2.72 per day. In the United States a course of treatment costs $100–200. As an antibiotic, benzylpenicillin is noted to possess effectiveness mainly against Gram-positive organisms. Some Gram-negative organisms such as "Neisseria gonorrhoeae" and "Leptospira
Penicillin Penicillin Penicillin (PCN or pen) is a group of antibiotics which include penicillin G (intravenous use), penicillin V (use by mouth), procaine penicillin, and benzathine penicillin (intramuscular use). Penicillin antibiotics were among the first medications to be effective against many bacterial infections caused by staphylococci and streptococci. They are still widely used today, though many types of bacteria have developed resistance following extensive use. About 10% of people report that they are allergic to penicillin; however, up to 90% of this group may not actually be allergic. Serious allergies only occur in about 0.03%. All penicillins are β-lactam antibiotics. Penicillin