What does the prescription "Lasix 20 mg tab i qd @ 9A and again at 3P prn edema" mean?

The prescription "Lasix 20 mg tab i qd @ 9A and again at 3P prn edema" conveys specific instructions for medication administration. The abbreviation 'qd' stands for "quaque die," which means "once a day." The term 'i' indicates a single tablet. The specification of '@ 9A and again at 3P' refers to the times of administration, denoting that the patient should take one tablet at 9 AM and again at 3 PM. The term 'prn' means "as needed," indicating that this medication should be used for the management of edema when necessary.

Therefore, the correct interpretation is that the patient should take 20 mg of Lasix each day at the designated times (9 AM and 3 PM) with the possibility of taking it more often if edema symptoms warrant additional doses. This highlights the importance of timing and symptom-driven usage in the management of conditions that require this medication, explaining why this choice accurately captures the intent of the prescription.