How to Solve IV Drug Dosage Problems with Dimensional Analysis

In nursing school, you will be required to show proficiency knowledge in drug dosage and calculations problems. In this article and video you will learn how to solve IV drug preparation problems. In the hospital setting, you may be requires to give Morphine 2 mg IV and the vial you are dispensed from pharmacy may say on it “4 mg/ml”. As a nurse, you will have to know how many ml you will need to draw up with your syringe before you give the medication to the patient.

Dimensional analysis is an easy problem-solving method to help you determine how much of a medication you should give based on the doctor’s order.

How to use Dimensional Analysis in Solving IV Drug Calculations

Before watching the video, be sure to download the worksheet that correlates with the material in the video. You can solve the drug problems as Sarah works them.

Free Quizzes

After you are done watching this video tutorial, test your knowledge by taking the IV bolus quiz.

IV Bolus Dosage Problems Solved using Dimensional Analysis

1. MD orders Morphine 0.5 mg IV every 4 hours as needed for pain. The vial is labeled 2 mg/ml. How many mL will you give per dose?

0.5 mg x 1 ml = 0.5 = 0.25 ml/dose

2. MD orders Versed 4 mg IV pre-procedural. The vial is labeled 1 mg/ml. How many mL will you give per dose?

4 mg x 1 ml = 4 = 4 ml/dose

3. MD orders Heparin 100 units subq daily. The vial is labeled 50 units/mL. How many mL will you give per dose?

100 units x 1 ml = 100 = 2 ml/dose

? dose 50 units 50

4. MD orders Benadryl 25 mg IV as needed for itching. The vial is labeled 1000 mcg/ml. How many mL will you give per dose?

25 mg x 1,000 mcg x 1 ml = 25,000 = 25 ml/dose

? dose 1 mg 1,000 mcg 1,000

5. MD orders Digoxin 0.125 mg IV stat. The vial is labeled 500 mcg/2ml. How many mL will you give per dose?

0.125 mg x 1,000 mcg x 2 ml = 250 = 0.5 ml/dose

? dose 1 mg 500 mcg 500

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