A nurse is preparing to administer ceftriaxone 400 mg IM to an infant in two divided doses. Available is ceftriaxone injection 500 mg/2 mL. How many total mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

Step 1: Determine the total dose of ceftriaxone to administer. The total dose prescribed is 400 mg. This dose will be divided into two equal doses for the infant. Step 2: Calculate the volume for each dose. The available ceftriaxone solution has a concentration of 500 mg in 2 mL. This means that 500 mg is present in 2 mL, so each mL contains 250 mg of ceftriaxone. To calculate how many mL are needed for the total dose of 400 mg, we use the following formula: Volume (mL)=Dose in mg/Concentration in mg/mL=400 mg/250 mg/mL=1.6 mL 1.6 /2 divided doses = 0.8mL Answer: 0.8mL