In medical dosing instructions, what does QID indicate?

• A. Four times daily.
• B. Every two hours.
• C. As needed.
• D. Once daily.

Answer: (A)

QID indicates four times a day. It comes from the Latin quater in die and tells you to distribute the dose across the 24-hour day—roughly every six hours—to keep the drug at a steady level. It’s not every two hours (that would be q2h), not “as needed” (that’s PRN), and not once daily (that’s QD). In practice, clinicians may specify exact times to avoid misreading and ensure consistent dosing.