Question

An intravenous dose of azithromycin is usually prepared by injecting a measured small amount of sterile water into a sealed vial containing a specifc known amount of solid formulation containing the medication and shaking the vial until all of it is dissolved. Te dosage to be administered to a patient is then removed (with a syringe) and added to a specifc volume of diluent solution, which is then administered as an IV drip. A diluent solution that is commonly used is 1/2 normal saline (0.45% sodium chloride solution). If an azithromycin formulation contains 500 mg of azithromycin and sterile water is added to make 5 mL of the formulation, how much must be removed with the syringe to add to the diluent solution for a dosage of 80 mg?

Answer 1

To administer an 80 mg dosage of azithromycin, the healthcare provider needs to withdraw 0.8 mL of the azithromycin solution prepared at 100 mg/mL concentration.

Step-by-step explanation:

To calculate the volume of the azithromycin solution needed to get an 80 mg dosage, we can set up a proportion based on the concentration of the stock solution. There are 500 mg of azithromycin in 5 mL, so we have a 100 mg/mL concentration. To find out how many milliliters contain 80 mg, we use the formula:

(500 mg/5 mL) = (80 mg/V1)

By cross-multiplying and solving for V1, we get:

V1 = (80 mg × 5 mL) / 500 mg

V1 = 0.8 mL

Therefore, to administer a dosage of 80 mg, the healthcare provider must draw up 0.8 mL of the azithromycin solution using a syringe to add to the diluent solution for the intravenous drip.