Preparing a Medication Order for Tobramycin in a Hospital Pharmacy

Introduction

A hospital pharmacy has available 2-ml prefilled syringes containing 80 mg of tobramycin and 1.5-ml prefilled syringes containing 60 mg of tobramycin. The syringes are calibrated in 0.25-ml units.

Preparing the Medication Order

In order to prepare a medication order calling for 110 mg of tobramycin to be added to 100 ml of d5w for intravenous infusion, you would follow these steps:

1. Draw up 80 mg from one 2 ml syringe
2. Draw up an additional 30 mg from a second 2 ml syringe
3. Add the total 110 mg of tobramycin to the 100 ml of d5w
4. Stir to ensure the medication is evenly distributed

Final Answer

To prepare an intravenous infusion of 110 mg tobramycin in 100 ml of d5w, draw up 80 mg from one 2 ml syringe and an additional 30 mg from a second 2 ml syringe, and add to the d5w. Stir to ensure the medication is evenly distributed.

Explanation

To prepare an intravenous infusion of 110 mg of tobramycin added to 100 ml of d5w, draw up the medication from the prefilled syringes. The 2-ml syringe contains 80 mg and the 1.5-ml syringe contains 60 mg of tobramycin. Hence, the concentration of tobramycin is 40 mg/ml in the 2-ml syringe and 40 mg/ml in the 1.5-ml syringe. To get the desired dose of 110 mg, you would need one full 2-ml syringe and about three-quarters (0.75 ml) of a second 2-ml syringe. This way, you get 80 mg from the first syringe and an additional 30 mg from the second syringe, making a total of 110 mg. Then, add these to the 100 ml of d5w for intravenous infusion. It's important to make sure that you're mixing well from time to time, especially before administration, to ensure even distribution of medication throughout the solution.