Pharmacy sig codes and days supply

You may see abbreviations in prescription directions. Many come from Latin, and patients may not understand them.

The pharmacist puts the directions on the medicine label. That tells the patient how much to take and how often.

The sig is a prescription's directions. Look for how much, which way, and how often. Their order can vary. How long appears only when it applies.

One tablet, by mouth, twice a day, for thirty days. Two times thirty is sixty tablets.

1 tab PO TID × 10 d. How many tablets do you dispense?

1. 10
2. 20
3. 30
4. 40

Answer: 30. TID is three times a day. 3 × 10 = 30.

Days supply runs the other way. Divide the quantity by the doses per day. Sixty tablets at two a day last thirty days.

You dispense 90 tablets. The sig reads 1 tab PO TID. What is the days supply?

1. 30 days
2. 45 days
3. 90 days
4. 270 days

Answer: 30 days. 30 days: TID is three doses a day, and 90 divided by 3 is 30. Dividing by 2 misreads TID as twice a day. 90 is the tablet count, and 270 multiplies instead of dividing.

Next lesson: Insulin and units