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The order is Penicillin G 1.2 million units IM daily. Available: Penicillin G 9 million units/1 ml. How many ml will you give?
- Mr. Q is a 56 y.o.male admitted to the hospital after a motor vehicle accident. His admission weight is 280 lbs. What is his admission weight in kg?
The Correct Answer and Explanation is:
Question 1: Dosage Calculation
Order: Penicillin G 1.2 million units IM daily
Available: Penicillin G 9 million units per 1 mL
Step 1: Set up the proportion 9 million units1 mL=1.2 million unitsx mL\frac{9\text{ million units}}{1 \text{ mL}} = \frac{1.2\text{ million units}}{x \text{ mL}}
Step 2: Solve for x x=1.29=0.133 mLx = \frac{1.2}{9} = 0.133 \text{ mL}
✅ Answer: You will give 0.133 mL of Penicillin G.
Question 2: Weight Conversion
Given:
- Weight = 280 lbs
- Conversion factor: 1 kg = 2.2 lbs
Step 1: Convert pounds to kilograms Weight in kg=2802.2=127.27 kg\text{Weight in kg} = \frac{280}{2.2} = 127.27 \text{ kg}
✅ Answer: Mr. Q’s weight is 127.27 kg
Explanation
Accurate medication dosage and weight conversions are critical in clinical practice to ensure patient safety and therapeutic effectiveness. The first question requires converting a medication dosage based on a concentration provided in units per milliliter. The ordered dose of Penicillin G is 1.2 million units IM (intramuscularly) daily, while the supply concentration is 9 million units per milliliter. This means the available medication is highly concentrated, so only a small volume (0.133 mL) is needed to deliver the prescribed dose. Administering the wrong volume, especially when the drug is so concentrated, could result in underdosing or overdosing, which may lead to treatment failure or adverse effects.
The second question involves converting body weight from pounds to kilograms, which is essential because most clinical dosages—particularly for medications like anesthetics, anticoagulants, or chemotherapeutics—are calculated based on body weight in kilograms. The conversion is performed using the standard formula: pounds divided by 2.2 equals kilograms. In this case, Mr. Q weighs 280 lbs, which converts to approximately 127.27 kg. This figure would be used for further calculations involving body surface area, fluid requirements, or dosing regimens.
Understanding both calculations reinforces foundational clinical math skills that nurses and other healthcare professionals must master. Errors in such conversions can lead to serious, sometimes fatal, medication errors. Therefore, it is essential to double-check calculations, use reliable conversion factors, and ensure that any drug administered is appropriate to the patient’s weight, age, and clinical condition.
