What does the abbreviation "qhs" commonly stand for in medical terms?

The abbreviation "qhs" stands for "quaque hora somni," which translates from Latin to "at every bedtime." This abbreviation is commonly used in medical prescriptions to indicate that a medication should be taken at bedtime, which helps healthcare providers communicate clear instructions for when to administer certain medications, particularly those that may cause drowsiness or require nighttime dosing.

The other options do not accurately reflect the meaning of "qhs." For instance, stating "every 2 hours" would typically be indicated by an abbreviation like "q2h," while "four times a day" would be represented as "q.i.d." or "4 times daily." The term "prescription" does not correspond to a specific dosing schedule and is more of a general term for a written order for medication. Thus, "qhs" is specifically associated with nighttime use, making it the correct choice.