Which term refers to substances that do not affect a medication's therapeutic action?

The term that refers to substances that do not affect a medication's therapeutic action is indeed "inactive ingredients." Inactive ingredients play a crucial role in the formulation of medications, as they serve various purposes that do not directly influence the drug's therapeutic effects. For instance, these substances can be used as fillers, stabilizers, preservatives, or to facilitate the delivery of the active ingredients.

Inactive ingredients are important for the overall composition of the medication. They can affect the drug's absorption, distribution, metabolism, and excretion, but they do not contribute to the desired therapeutic outcome. This distinction is significant in understanding how medications are formulated and how they function within the body. Knowing about inactive ingredients helps healthcare professionals and patients appreciate the full makeup of a medication, which can be important for individuals with allergies or sensitivities to specific compounds.

While excipients are technically a subset of inactive ingredients, referring specifically to substances used to formulate a drug's product form, the broader category of inactive ingredients encompasses all components that do not have therapeutic properties. Therefore, understanding the role of inactive ingredients reinforces the overall knowledge of pharmacology and medication management.