Medication administration - Pediatric: Nursing pharmacology

Physiological differences between children and adults alter the way medications are absorbed, distributed, metabolized, and eliminated, which means children require different dosages of medications and special techniques for administration. Most pediatric medications are dosed according to the patient’s current weight using either a prescribed dosage per kilogram of body weight or body surface area, known as BSA.  

Now, oral medications for pediatric patients are often formulated in a liquid or suspension. When measuring the quantity of a medication, be sure to use the measuring device supplied with the medication, like a dropper, oral syringe, spoon, or cup as these are calibrated to allow accurate measurement of a specific medication. 

As the nurse, you’ll perform medication calculations to ensure the correct dose of medication is administered.  

To calculate a dose using the Dimensional Analysis, or DA method, the three components you need are D, for the Desired dose, or dose ordered by the health care provider; H, for Have, or the dosage you have available; and V, for Vehicle or the form and amount in which the medication comes, like tablets or liquid.      Let’s look at a pediatric oral dosage calculation where a weight-based calculation is required.  

First, you’ll read the order which is: amoxicillin 15 milligrams per kilogram PO every 8 hours. 

Then, check the medication label.

Since the medication comes in 125 milligrams per 5 milliliters, you’ll calculate how many milliliters you should administer to achieve the Desired dose. To do this, first identify your components, Desired, Have, and Vehicle.   In this case, D is 15 milligrams per kilogram, which was obtained from the health care provider’s order. H is 125 milligrams, which was obtained from the medication label. And V is 5 milliliters, which was also obtained from the medication label. You also need to know the patient’s weight, which is 33 pounds. 

Next, you’ll determine if a conversion factor is required. Since the ordered dose is in milligrams per kilogram and your patient’s weight is in pounds, a conversion factor is needed. In this case, you’ll use the following conversion factor for kilograms to pounds: 

1 kilogram equals 2.2 pounds 

Now, you can convert the patient’s weight to kilograms before completing the rest of the calculation, which looks like this:   

X volume in milliliters equals Vehicle over Have multiplied by Desired multiplied by Weight in kilograms.         Or you can place the conversion into the equation which looks like this: 

X volume in milliliters equals Vehicle over Have multiplied by Desired multiplied by Weight in pounds multiplied by the Conversion factor for kilograms over the Conversion factor for pounds.  

Now, plug in the values for the components. Since the Desired dose is 15 milligrams per 1 kilogram, the 1 kilogram is placed in the denominator of the equation. This gives you X equals 5 milliliters multiplied by 15 milligrams multiplied by 33 pounds multiplied by 1 kilogram divided by 125 milligrams multiplied by 1 kilogram multiplied by 2.2 pounds. 

Remember, you can cross out the units of the numerator that match the units of the denominator, because they cancel out. 

Now you’ll multiply the numbers in the numerator and then the numbers in the denominator to get 2475 milliliters divided by 275. 

Next, divide 2475 milliliters by 275 to solve for X. 

X = 9 mL 

This gives you the final answer of 9 milliliters meaning you should administer 9 milliliters of amoxicillin to achieve the prescribed dose of 15 milligrams per kilogram. 

Intramuscular, or IM injection is another route of medication administration in pediatric patients. IM injections can cause pain and anxiety in children. Measures like breastfeeding, topical anesthetics, oral sucrose, or distraction during the injection may minimize your patient’s pain and anxiety. After the injection, comfort measures should be implemented.  

Also be sure to consider the medication type, volume, and size of your patient when choosing the appropriate injection site such as the vastus lateralis and the rectus femoris muscles of the thigh, the dorsal and ventrogluteal muscles of the buttocks, and the deltoid muscle of the upper arm. It’s also important to select the correct needle length and gauge for pediatric patients depending on their size and the viscosity of the medication. The typical needle length used in pediatric patients is between 5/8 and 1 inch long, and gauge ranges from 22 to 27. 

Okay, now let’s look at an IM dosage calculation where a weight-based calculation is required. 

First, read the order which is: dexamethasone 0.6 milligrams per kilogram intramuscular injection STAT. 

Then, check the medication label.