Final answer:
The nurse should report the client's penicillin allergy to the provider before starting cefotetan.
Step-by-step explanation:
The nurse should report to the provider that the client has a penicillin allergy before starting cefotetan. Cefotetan is in the same class of antibiotics as penicillin and can cause an allergic reaction in individuals who are allergic to penicillin. It is important for the provider to be aware of this allergy to avoid any potential complications.