Before administering a cephalosporin to a patient, it is most important for the nurse to assess the patient for an allergy history to which substance?

Before administering a cephalosporin to a patient, it is most important for the nurse to assess the patient for an allergy history to penicillin. The drug cephalosporins belong to the group of beta-lactam antibiotics which has a similar structure and as well as action to that of penicillin. If a patient has allergy reaction of penicillin, then surely the patient would not be able to take in cephalosporins.   This antibiotic is produced from the fungus Acremonium. It is being used to treat infections that are caused by bacteria which is susceptible to this type of antibiotic. The first generation of this antibiotic was made to kill gram-positive bacteria and it was further developed for it to have increased activity to gram negative bacteria.