1. Jennifer is to receive gentamicin 12 mg IM.  How many milliliters should you withdraw from a vial that has a concentration of 40 mg/ml?
2. Aqueous penicillin 125,000 units IM is ordered for an infant. You find a one million unit vial of power in his drug drawer. Reconstitution instructions on the vial tell you to add:
3. Tony is to receive nafcillin 150 mg IM. There is a vial of nafcillin in Tony’s drug drawer. The directions on the vial state that when reconstituted with 3.4 ml sterile water for injection, each vial contains 4 ml solution of sodium nafcillin equivalent to 250 mg nafcillin per ml, buffered with 10 mg sodium citrate. How many mls of nafcillin should you give Tony?
4. Your drug book states that the recommended dose of phenobarbital for a child is 6mg/kg/24 hours. Donna weighs 11 pounds 5 ounces and has a phenobarbital order for 8 mg three times per day. What is the recommended dose? Is Donna dose of phenobarbital correct? if not, is the dose too high or too low?
5. A 2 1/2 year old is order to receive IV cefotaxime 1200 mg/day. The child weighs 14kg. The Pediatric dosage handbook states that the dosage of cefotaxime is 100-200mg/kg/day. What is the recommended dose range? Is this child’s ordered dose within the recommended dose range?

ANSWER

 Medication Calculations and Pediatric Dosing: A Comprehensive Analysis

Introduction

Accurate medication calculations and appropriate pediatric dosing are crucial aspects of nursing practice to ensure patient safety and optimal therapeutic outcomes. This essay addresses various medication calculation scenarios, including gentamicin administration, penicillin reconstitution, nafcillin dosage determination, phenobarbital dosing evaluation, and cefotaxime dosing assessment.

Gentamicin Dosing Calculation

For Jennifer’s gentamicin dose of 12 mg IM and a concentration of 40 mg/ml, the calculation is as follows:

\[ \text{Volume (ml)} = \frac{\text{Dose (mg)}}{\text{Concentration (mg/ml)}} \]
\[ \text{Volume (ml)} = \frac{12 \, \text{mg}}{40 \, \text{mg/ml}} = 0.3 \, \text{ml} \]

Jennifer should receive 0.3 ml of gentamicin.

Penicillin Reconstitution

For an infant requiring 125,000 units of penicillin and a one million unit vial of powder, the reconstitution ratio is 1:8. Therefore, to reconstitute, add 1 ml of diluent for every 8 ml of powder.

Nafcillin Dosage Calculation

For Tony’s nafcillin dose of 150 mg IM, each vial of reconstituted solution contains 250 mg nafcillin per ml. Since each vial contains 4 ml solution, the calculation is:

\[ \text{Dose (ml)} = \frac{\text{Dose (mg)}}{\text{Concentration (mg/ml)}} \]
\[ \text{Dose (ml)} = \frac{150 \, \text{mg}}{250 \, \text{mg/ml}} = 0.6 \, \text{ml} \]

Tony should receive 0.6 ml of nafcillin.

Phenobarbital Dosing Evaluation

Donna’s weight is 11 pounds 5 ounces, which is approximately 5.2 kg. The recommended dose of phenobarbital is \( 6 \, \text{mg/kg/24 hours} \), and Donna has an order for 8 mg three times per day.

\[ \text{Recommended Dose} = 6 \, \text{mg/kg/24 hours} \times 5.2 \, \text{kg} = 31.2 \, \text{mg/24 hours} \]

Donna’s ordered dose is \( 8 \, \text{mg} \times 3 = 24 \, \text{mg/24 hours} \).

Donna’s ordered dose of 24 mg is lower than the recommended dose of 31.2 mg, making it appropriate.

Cefotaxime Dosage Assessment

The child’s weight is 14 kg, and the recommended dosage range of cefotaxime is 100-200 mg/kg/day.

\[ \text{Minimum Dose} = 100 \, \text{mg/kg/day} \times 14 \, \text{kg} = 1400 \, \text{mg/day} \]
\[ \text{Maximum Dose} = 200 \, \text{mg/kg/day} \times 14 \, \text{kg} = 2800 \, \text{mg/day} \]

The child’s ordered dose of 1200 mg/day falls within the recommended dose range of 1400-2800 mg/day.

Conclusion

Accurate medication calculations and pediatric dosing are paramount in nursing practice. Through these calculations and evaluations, we can ensure that patients receive the right medications in the right doses, maximizing therapeutic effects and minimizing the risk of adverse events.