Injected directly into a vein.

• A. Intravenously
• B. Intramuscularly
• C. Subcutaneously
• D. Oral administration

Answer: (A)

Injecting directly into a vein means delivering the substance straight into the bloodstream, which is called intravenous administration. This route provides instant access to circulation, so effects come on very quickly. That rapid onset is the defining feature of IV delivery.

Other common routes differ in how they reach the bloodstream: intramuscular injections place the drug into muscle tissue, where it must be absorbed into the blood, leading to a slower onset. Subcutaneous injections go under the skin and are absorbed even more slowly. Oral administration involves swallowing the substance, so it must pass through the digestive system and liver first, often producing even slower and more variable effects. In clinical and counseling contexts, intravenous use offers fast onset but also carries risks like vein damage, infections, and potential complications from injecting into the bloodstream.