A nurse is preparing to administer amoxicillin 320 mg PO every 12 hours to an infant. The amoxicillin suspension available is 400 mg/5 mL. How much should the nurse give?

To determine the correct dosage of amoxicillin to administer, it's important to first understand the concentration of the suspension available and then calculate the appropriate volume needed to deliver the prescribed dose.

The amoxicillin suspension is provided at a concentration of 400 mg per 5 mL. This indicates that every 5 mL of the suspension contains 400 mg of amoxicillin. To find out how much volume is needed to achieve a dose of 320 mg, we can set up a proportion based on the concentration:

1. First, find the concentration in mg/mL:

   • 400 mg / 5 mL = 80 mg/mL.

2. Next, to find out how many mL contains 320 mg, we can use the formula:

   • Volume (mL) = Dose (mg) / Concentration (mg/mL).
   • Volume = 320 mg / 80 mg/mL = 4 mL.

Thus, the nurse should administer 4 mL to achieve the correct dose of 320 mg of amoxicillin. This confirms that the correct answer is indeed 4 mL.