National Certified Addiction Counselor, Level 2 (NCAC II) Practice Exam Exam

In the process of drug administration, which route is likely to act the fastest?

1. Oral

2. Inhalation

3. Transdermal

4. Injection

The correct answer is: Injection

The route of drug administration that acts the fastest is injection. This method delivers the drug directly into the bloodstream, allowing for immediate absorption and onset of action. When a drug is injected—whether intravenously, intramuscularly, or subcutaneously—it bypasses the gastrointestinal tract and liver, which means it does not undergo the delay associated with processing that occurs with oral routes. Injection is particularly advantageous in emergency situations or when rapid effects are necessary, such as in cases of severe pain management or life-threatening conditions. Consequently, drugs administered via injection achieve peak plasma concentrations more quickly compared to other routes, leading to a faster therapeutic effect. Inhalation is also a fast-acting route, as it allows drugs to diffuse rapidly into the bloodstream through the lungs, but it typically does not surpass the immediacy of IV injections. Oral administration involves digestion and absorption phases, significantly delaying onset. Transdermal delivery requires the drug to penetrate the skin, which can also result in delayed effects. Thus, injection stands out as the route providing the quickest drug action.