Ordered is cephalothin 500 mg IM. The medication label states: the addition or 4 ml of sterile water yields 0.5 g in 2.2 ml of suspension
What is the Rx? And S? Show all work
Rx: Cephalothin 500 mg IM
S: Add 4 ml of sterile water to yield 0.5 g in 2.2 ml of suspension
To find the concentration of cephalothin in the suspension, we can use the equation:
Concentration (C) = amount of drug (A) / volume of solution (V)
Given information:
1 g of cephalothin is equivalent to 1000 mg
Amount of drug (A) = 500 mg
Volume of solution (V) = 2.2 ml
Concentration (C) = A / V = 500 mg / 2.2 ml = 227.27 mg/ml
We are given that adding 4 ml of sterile water yields 0.5 g (500 mg) of cephalothin in 2.2 ml of suspension. Therefore, we need to find the amount of water required to dissolve 500 mg of cephalothin.
Let x be the amount of water in ml.
Since we are adding 4 ml of sterile water in total, the volume of the suspension will be 2.2 ml + x ml.
Now we can set up a proportion to solve for x:
500 mg / 2.2 ml = 500 mg / (2.2 ml + x ml)
Cross multiplying, we get:
500 mg * (2.2 ml + x ml) = 500 mg * 2.2 ml
Simplifying, we have:
1100 ml * mg + 500 mg * x ml = 1100 mg * ml
Dividing both sides by 500 mg, we have:
2.2 ml + x ml = 2.2 ml
Subtracting 2.2 ml from both sides, we get:
x ml = 0 ml
This tells us that no additional water is needed to dissolve 500 mg of cephalothin in 2.2 ml of suspension. Therefore, the Rx is to add 4 ml of sterile water to yield 0.5 g in 2.2 ml of suspension.
The Rx is the prescription, and the S is the solution.
Given information:
Cephalothin 500 mg IM
Medication label ratio: 4 ml of sterile water + 0.5 g = 2.2 ml
To find the solution (S), we need to determine how much sterile water is needed to make the suspension specified in the medication label.
Let's set up a proportion to solve for S:
4 ml of sterile water / 0.5 g of cephalothin = S ml of sterile water / 500 mg of cephalothin
Cross-multiplying, we get:
4 ml * 500 mg = 0.5 g * S ml
2000 mg ml = 0.5 g * S ml
Since 1 gram is equivalent to 1000 milligrams, we can convert 0.5 g to 500 mg:
2000 mg ml = 500 mg * S ml
Dividing both sides by 500 mg, we find:
S ml = 2000 mg ml / 500 mg
S ml = 4 ml
Therefore, the solution (S) is 4 ml of sterile water.
The Rx (prescription) is to add 4 ml of sterile water to the cephalothin to yield a suspension of 0.5 g in 2.2 ml.