Question

A physician orders 125 mg/5 ml Dilantin suspension to replace an order reading, "Dilantin 100 mg, Dispense: #30, Sig: t.i.d" What quantity of suspension should be dispensed?

1) 100 ml
2) 120 ml
3) 300 ml
4) 360 ml

Answer 1

To calculate the quantity of Dilantin suspension to be dispensed, we determine that 4 ml of suspension contains 100 mg of Dilantin. The patient takes this dosage three times a day, which amounts to 12 ml per day. For a 10-day supply, the total quantity needed is 120 ml.

Step-by-step explanation:

The question involves calculating the quantity of suspension to be dispensed for the medication Dilantin. The dosage prescribed is 100 mg of Dilantin to be taken three times a day (t.i.d), and we have a suspension that has a concentration of 125 mg/5 ml.

To find out how much suspension equals 100 mg, we use the following ratio: (125 mg : 5 ml = 100 mg : x ml). Solving for x gives us (x = 100 mg * 5 ml / 125 mg), which simplifies to 4 ml. Since the medication needs to be taken three times a day, we then calculate the total daily amount: (4 ml per dose * 3 doses per day = 12 ml per day).

As the prescription is to dispense #30, which represents a 10 day supply (30 tablets/tablet 3 times a day = 10 days), we need 10 days' worth of suspension. The final step is to multiply the daily amount by the number of days: (12 ml per day * 10 days = 120 ml). Therefore, the correct quantity of suspension to dispense is 120 ml.