# Safe Dose Range

Clinical Case Study B, Chapter 8, Dosage Problems for Infants and Children

Ebonee Parker, age 9, is admitted to the oncology unit for chemotherapy for acute lymphocytic leukemia. Weight is 60 pounds, height is 60 inches, BSA 1.05. (Topics covered: converting pounds to kilograms, determining a safe dose, mg/kg calculations, body surface area calculations)

Medication orders:

• asparaginase 27,000 international units in 50 mL D5W, IVPB. Infuse over 30 minutes
• prednisone 15 mg po q 8 hours
• vincristine 2 mg in 50 mL D5W, IVPB. Infuse in 15 minutes
• morphine 1.5 mg IVP q 6 hours prn pain
• dexamethasone 4 mg IVP bid
• ondansetron 4 mg IVP 30 minutes prior to chemotherapy, repeated 4 and 8 hours later
• Primary IV: D5W 50 mL/hour × 24 hours

Calculate the safe dose, determine if the ordered dose is safe, and calculate the amount needed for the correct dose (round the weight conversion to a whole number; do not round answers unless directed):

1. asparaginase. Safe dose: 25,000 international units/m2 3 times a week. Supply: 10,000 units/mL. What is the infusion rate?
2. prednisone. Safe dose: 40 mg/m2 po in divided doses, q 8 hours. Supply: oral solution 5 mg/5 mL
3. vincristine. Safe dose: 1.5–2 mg/m2 single dose. Supply: 1 mg/mL
4. morphine. Safe dose: 0.05 mg/kg/dose. Supply: 2 mg/mL
5. dexamethasone. Safe dose: 0.08 to 0.3 mg/kg/day divided q 12 hours. Available: 4 mg/mL injection
6. ondansetron. Safe dose: 0.15 mg/kg IVP. Supply: 2 mg/mL
7. What is the total amount of the primary infusion in 24 hours?

Critical Error:

The nurse does not calculate the safe dose (range) and accepts the medication orders as written. What error could happen?

Critical Error:

By not calculating the safe dose range for each medication, the nurse risks administering doses that could be either too high or too low for the patient’s condition. This error could lead to adverse effects, inadequate treatment efficacy, or toxicity. For example:

1. Administering an excessive dose of chemotherapy drugs like asparaginase or vincristine could lead to severe adverse reactions, including organ damage or exacerbation of the patient’s condition.
2. Under-dosing medications like prednisone or morphine may result in inadequate symptom control or therapeutic effect, compromising the patient’s comfort and treatment outcome.
3. Failure to adjust medication doses based on the patient’s weight and body surface area may lead to incorrect dosing, posing risks of treatment failure or harm.
4. Inadequate prophylactic dosing of antiemetics like ondansetron may result in insufficient control of chemotherapy-induced nausea and vomiting, impacting the patient’s comfort and compliance with treatment.

Overall, not calculating the safe dose range increases the likelihood of medication errors, compromises patient safety, and may hinder treatment effectiveness in managing the patient’s condition.

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