Which statement about IV administration is true?

Which statement about IV administration is true?

• A. It requires gastric residence time
• B. It cannot deliver large volumes
• C. It always delivers drug slower than oral dosing
• D. It bypasses the absorption phase

Answer: (D)

The key idea is that intravenous administration places the drug directly into the bloodstream, so there is no dissolution, permeation across the gut wall, or transit through the GI tract to reach systemic circulation. Because of this, the absorption phase is effectively bypassed—the drug is immediately available in the circulation and its onset depends on distribution and elimination rather than absorption. This is why IV can achieve rapid or immediate systemic exposure (bioavailability is essentially 100% for IV). The other statements don’t fit: gastric residence time isn’t required since the drug never sits in the stomach; large volumes can be delivered by IV infusion (so claiming it cannot deliver large volumes is incorrect); the onset is not inherently slower than oral dosing and is often faster; and while IV bypasses the absorption phase, hepatic metabolism can still occur after the drug is in the bloodstream, but that concerns distribution and clearance, not absorption. Therefore, the statement that IV administration bypasses the absorption phase is the accurate one.

The key idea is that intravenous administration places the drug directly into the bloodstream, so there is no dissolution, permeation across the gut wall, or transit through the GI tract to reach systemic circulation. Because of this, the absorption phase is effectively bypassed—the drug is immediately available in the circulation and its onset depends on distribution and elimination rather than absorption.

This is why IV can achieve rapid or immediate systemic exposure (bioavailability is essentially 100% for IV). The other statements don’t fit: gastric residence time isn’t required since the drug never sits in the stomach; large volumes can be delivered by IV infusion (so claiming it cannot deliver large volumes is incorrect); the onset is not inherently slower than oral dosing and is often faster; and while IV bypasses the absorption phase, hepatic metabolism can still occur after the drug is in the bloodstream, but that concerns distribution and clearance, not absorption. Therefore, the statement that IV administration bypasses the absorption phase is the accurate one.