A patient is receiving morphine sulfate intravenously via a patient controlled analgesia (PCA) pump. The concentration of the solution is 15 mg/mL and is being infused at a rate of 0.1 mL/h. The patient may access a 2-mg bolus dose every hour for breakthrough pain and is currently using an average of 8 doses per day. The patient’s caregiver requests that the patient be converted to oxycodone oral tablets given every 4 hours. Calculate the appropriate dose of oral oxycodone using the dosing tablets used in class. Round to the tenths place and use the appropriate units. None QUESTION 10 A patient is receiving morphine sulfate intravenously via a patient controlled analgesia (PCA) pump. The concentration of the solution is 15 mg/mL and is being infused at a rate of 0.1 mL/h. The patient may access a 2-mg bolus dose every hour for breakthrough pain and is currently using an average of 8 doses per day. The patient’s caregiver requests that the patient be converted to oxycodone oral tablets given every 4 hours. Calculate the appropriate dose of oral oxycodone using the dosing tablets used in class. Round to the tenths place and use the appropriate units.
The correct answer and explanation is:
Answer
The appropriate dose of oral oxycodone to administer every 4 hours is 10 mg.
Calculation and Explanation
1. Determine total daily morphine dose (IV):
- Continuous infusion dose:
- Morphine concentration: 15 mg/mL.
- Infusion rate: 0.1 mL/h.
- Morphine infused per hour: 15 mg/mL×0.1 mL/h=1.5 mg/h15 \, \text{mg/mL} \times 0.1 \, \text{mL/h} = 1.5 \, \text{mg/h}.
- Total infusion dose in 24 hours: 1.5 mg/h×24 h=36 mg/day.1.5 \, \text{mg/h} \times 24 \, \text{h} = 36 \, \text{mg/day}.
- Bolus dose:
- Dose per bolus: 2 mg.
- Average boluses per day: 8 doses.
- Total bolus dose in 24 hours: 2 mg/bolus×8 boluses=16 mg/day.2 \, \text{mg/bolus} \times 8 \, \text{boluses} = 16 \, \text{mg/day}.
- Total daily IV morphine dose:
- 36 mg/day (infusion)+16 mg/day (bolus)=52 mg/day.36 \, \text{mg/day (infusion)} + 16 \, \text{mg/day (bolus)} = 52 \, \text{mg/day}.
2. Convert IV morphine to oral morphine:
- Conversion factor for IV to oral morphine: 1:31:3.
- Oral morphine dose: 52 mg/day×3=156 mg/day.52 \, \text{mg/day} \times 3 = 156 \, \text{mg/day}.
3. Convert oral morphine to oral oxycodone:
- Conversion factor for oral morphine to oral oxycodone: 1:1.51:1.5.
- Oral oxycodone dose: 156 mg/day÷1.5=104 mg/day.156 \, \text{mg/day} \div 1.5 = 104 \, \text{mg/day}.
4. Determine oxycodone dose every 4 hours:
- Dosing frequency: every 4 hours (66 doses/day).
- Dose per administration: 104 mg/day÷6=17.3 mg104 \, \text{mg/day} \div 6 = 17.3 \, \text{mg}.
- Round to the nearest dose appropriate for tablets (e.g., 10 mg or 15 mg tablets are standard). The closest dose is 10 mg every 4 hours.
5. Rationale for the calculation:
- Accurate conversion ensures effective pain control without over-sedation.
- Conversion factors account for differing bioavailability and potency between morphine (IV and oral) and oxycodone.
- Oxycodone’s frequent dosing interval helps manage continuous and breakthrough pain.
Always verify with prescribing guidelines or adjust for individual patient needs as required.