A client receives a prescription for ondansetron 4 mg IV. The medication available is 2 mg/ml. How many ml should the nurse administer?

To determine the correct volume of ondansetron to administer, you first need to establish how many milliliters are required to achieve the prescribed dose of 4 mg. The medication available is at a concentration of 2 mg per milliliter (ml).

Using a simple calculation, you can figure out the amount of medication needed:

1. Divide the desired dose (4 mg) by the concentration (2 mg/ml):

( \text{Volume needed (ml)} = \frac{\text{Desired dose (mg)}}{\text{Concentration (mg/ml)}} )

( \text{Volume needed (ml)} = \frac{4 \text{ mg}}{2 \text{ mg/ml}} = 2 \text{ ml} )

This calculation shows that to achieve a dose of 4 mg, the nurse should administer 2 ml of the ondansetron solution. The concentration of 2 mg/ml directly informs the amount needed, allowing for a straightforward conversion from the prescribed dosage to the volume to be administered. Thus, administering 2 ml will provide the required 4 mg dose of ondansetron safely and effectively.