Which substance should not be administered to a patient with a history of anaphylaxis?

When considering substances that should not be administered to a patient with a history of anaphylaxis, gelatin is often a concern. Gelatin is a protein derived from collagen and is commonly found in some vaccines and medical products. While gelatin can provoke allergic reactions in sensitive individuals, the specific concern in this context is its use in vaccines that may contain it as a stabilizer.

Patients with a documented history of anaphylaxis to gelatin are at risk for serious reactions, so it is prudent to avoid administering any products containing gelatin. This is particularly important in vaccine administration where anaphylactic reactions to excipients like gelatin have been documented.

In the case of the other substances, while they can also cause allergic reactions in some individuals, the primary focus here is on the direct relevance to anaphylaxis caused by gelatin-based products. Thus, avoiding gelatin is a key precaution for individuals with such a history to ensure their safety.