Which of the following is an example of an auxiliary label that may be attached to a prescription bottle?

An auxiliary label is a supplementary label attached to a prescription bottle to provide patients with important information about the medication's use, side effects, or special instructions. The correct choice includes examples like "Take with food" or "May cause drowsiness."

These labels serve to enhance patient safety and compliance by offering clear instructions on how to take the medication effectively and what potential side effects to be aware of. For instance, informing patients that a medication may cause drowsiness helps them to make informed decisions about activities requiring alertness, such as driving or operating machinery.

Other options, while related to prescriptions, do not fall under the typical category of auxiliary labels used for day-to-day medication instructions. For example, "Prescription refill required" is more of a pharmacy administrative note rather than a patient-focused advisory. "Take on an empty stomach" might also be seen as an auxiliary label, but it is specific and not as commonly used as the examples given in the correct answer. "To be taken once a week" is more of a dosing schedule rather than a typical auxiliary instruction and lacks the additional guidance on potential effects or interactions that auxiliary labels usually provide.