Which of the following is NOT a listed route for fentanyl administration?

• A. Intravenous
• B. Subcutaneous injection
• C. Intranasal
• D. Iontophoretic transdermal

Answer: (B)

Fentanyl is delivered through routes chosen to balance how quickly it works with how long it lasts. Intravenous administration provides immediate plasma levels, making it ideal for rapid control of pain or during anesthesia. Intranasal delivery takes advantage of the rich vascular supply of the nasal mucosa for quick, noninvasive absorption, useful for rescue or breakthrough analgesia. Iontophoretic transdermal delivery uses a small electric current to drive fentanyl through the skin, offering a controlled, sustained exposure without a traditional patch. Subcutaneous injection, while possible as a parenteral method, is not typically listed as a standard fentanyl administration route in common references or labeling, so it doesn’t fit with the other listed, well-recognized routes.