What is the purpose of the abbreviation "sig." on a medication label?

The abbreviation "sig." on a medication label is derived from the Latin word "signa," which translates to "to label" or "to write." This part of the prescription is crucial because it provides specific instructions on how the patient should take the medication. This includes details such as the dose, route, frequency, and any other pertinent instructions. Thus, its purpose is to ensure that the patient understands how to properly use the medication as directed by the prescribing healthcare professional.

In the context of the other choices, while dosage guidance is indeed part of what "sig." includes, it does not encompass the full range of instructions that may be provided under this abbreviation, which can also specify timing and way of administration. Side effects are typically not covered under "sig.," as they are usually noted elsewhere on the label or included in patient information leaflets. The prescription refill policy is also separate from "sig." instructions, as it pertains to how many times and under what circumstances a medication prescription can be refilled. Finally, labeling information generally refers to additional data provided on the medication label like warnings, which is distinct from the direct instructions given by "sig."