If a person has a penicillin allergy, which medication should be questioned if ordered?

Ceftriaxone, a cephalosporin antibiotic, should be questioned if a patient has a penicillin allergy. This is due to the structural similarities between penicillins and cephalosporins, which can lead to cross-reactivity in individuals who are allergic to penicillin. Although the majority of patients with a penicillin allergy do not show cross-reactivity to cephalosporins, there is still a significant percentage that may experience allergic reactions. Therefore, careful assessment and questioning are warranted when prescribing ceftriaxone for someone with a known penicillin allergy.

In contrast, amoxicillin is a type of penicillin; therefore, it should not be prescribed to anyone with a penicillin allergy. Doxycycline and ciprofloxacin are both from different classes of antibiotics—tetracyclines and fluoroquinolones, respectively—and do not share structural properties with penicillins, making them safer alternatives for individuals with a penicillin allergy.