A prescription calls for erythromycin 400mg/5ml, dispense 100ml. The dose is 40mg/kg/day and the child weighs 44 pounds. The si. reds ? tsp qid until gone. How many tsp and how many days will the prescription last?.
40mg/kg*1kg/2.2 lbs*44lbs=800mg/day. Assume each tsp contains 5ml which is very close to 5grams, or 400mg per tsp.
so to get 800mg/day, you need 1/2 tsp 4x a day. It will last....100ml/10tsp*5ml/tsp=4 days.
check me on this.
oops 100/50 is two days. Goodness. I will get someone to check this, a smart nurse would help.
Actually, you are right in your calculation of 1/2 tsp 4 times a day. But that means you will use a total of 2 teaspoons per day. 1 tsp is 5ml so that means 10ml used per day. If there is 100ml in the bottle, then this is a 10 day supply. (100ml÷10ml/day)
thanks, Dr Sarah.
To determine the number of teaspoons and the number of days the prescription will last, we need to follow these steps:
1. Convert the weight from pounds to kilograms:
- Divide the weight in pounds (44 pounds) by 2.2046 to get the weight in kilograms.
- 44 pounds ÷ 2.2046 = 19.958 kg (approximately)
2. Calculate the total daily dose:
- Multiply the weight in kilograms by the prescribed dose per kilogram.
- 19.958 kg × 40 mg/kg/day = 798.32 mg/day (approximately)
3. Calculate the number of teaspoons per day:
- Divide the total daily dose (798.32 mg) by the concentration of erythromycin (400 mg/5 ml).
- 798.32 mg ÷ 400 mg/5 ml = 9.982 tsp/day (approximately)
4. Determine the number of teaspoons per dose:
- Divide the total teaspoons per day by the number of doses given in a day (qid = 4 times a day).
- 9.982 tsp/day ÷ 4 doses/day = 2.4955 tsp/dose (approximately)
5. Calculate the number of days the prescription will last:
- Divide the total quantity (100 ml) by the number of teaspoons per dose (2.4955 tsp/dose).
- 100 ml ÷ 2.4955 tsp/dose = 40.079 days (approximately)
So, the prescription will last approximately 40 days, and each dose is approximately 2.5 teaspoons.