Final answer:
The pharmacist would likely contact the physician to consider changing the prescribed antibiotic due to the patient's history of severe allergic reaction to penicillin, as Velosef belongs to the cephalosporin class which can cross-react with penicillins.
Step-by-step explanation:
The pharmacist would likely call the physician to change the antibiotic for the woman with a severe allergic reaction to penicillin. Velosef contains cefradine, which is a cephalosporin antibiotic, and while it is a different class of antibiotics, there is a known cross-reactivity risk between penicillins and cephalosporins.
Penicillin-allergic patients can sometimes have similar reactions to cephalosporins due to the similarity in their beta-lactam ring structures. The woman's reported reaction to penicillin, which included throat swelling and difficulty breathing, suggests that she experienced an anaphylactic reaction, which is life-threatening. It is a standard practice to avoid prescribing medication from the cephalosporin class to someone with a history of anaphylaxis to penicillin due to the potential for severe allergic reactions or cross-reactivity.