Final answer:
The student should dispense 4 vials of Zantac® injection, as the total required dosage is 22.5 ml and each vial contains 6 ml. Partial vials are not dispensed, so the total is rounded up to the next whole vial.
Step-by-step explanation:
The question requires the calculation of how many vials of Zantac® injection should be dispensed based on the doctor's prescription and the concentration of the medication available on hand. The doctor ordered Zantac 37.5 mg IM q8h for 5 days. The medication on hand is Zantac® injection at a concentration of 25 mg/ml in 6 ml multidose vials.
To find out how many milliliters are needed per dose, we divide the ordered dose by the concentration:
37.5 mg ÷ 25 mg/ml = 1.5 ml per dose
Next, we'll determine the total number of doses:
There are 3 doses per day (every 8 hours) for 5 days, which equals 3 × 5 = 15 doses. Now we can calculate the total volume needed:
1.5 ml per dose × 15 doses = 22.5 ml
Since each vial contains 6 ml, we divide the total volume by the volume per vial and round up to the nearest whole number:
22.5 ml ÷ 6 ml/vial = 3.75 vials
Since partial vials are not dispensed, you would round up to 4 vials to be dispensed.