The primary injectable drug for acute allergic reaction (anaphylaxis) is epinephrine. Which concentration is designed for intramuscular (IM) administration?

Epinephrine is the first-line treatment for acute allergic reactions, particularly anaphylaxis, due to its ability to rapidly reverse the symptoms by acting on alpha and beta-adrenergic receptors. The concentration specifically designed for intramuscular administration in emergency situations is 1:1,000.

This concentration provides a balance of efficacy and safety for IM injections, allowing for quick absorption into the bloodstream and prompt action against the life-threatening symptoms of anaphylaxis, such as bronchospasm, hypotension, and skin reactions.

The other concentrations listed serve different purposes or routes of administration. For example, a concentration of 1:100 is typically used for topical administration and may not be appropriate for IM use. The 1:10,000 concentration is usually reserved for intravenous administration in a hospital setting, where careful monitoring can occur. Lastly, the 1:100,000 concentration is often used in local anesthetics but is not suitable for the urgent needs presented in anaphylaxis. Thus, 1:1,000 is the correct choice for intramuscular injection.