What statement best describes a drug that is pyrogen-free?

• A. It does not contain preservatives.
• B. It is free of side effects.
• C. It does not contain heavy metals.
• D. It does not cause a fever.

Answer: (D)

A pyrogen-free drug is free of substances that induce fever. Pyrogens, such as bacterial endotoxins, trigger a fever response when they enter the bloodstream. By removing these contaminants and testing to ensure endotoxin levels are below safe thresholds, the product should not raise body temperature. That’s why the best description is that it does not cause a fever. The other concepts—preservatives, lack of side effects, or absence of heavy metals—are about different quality attributes and do not define pyrogenicity.