Help with a dosage calculation

[dannyb83]

A nurse is preparing administer ampicillin 25 mg/kg PO divided in equal doses every 12 hrs to an adolescent who weighs 99 lbs.The amount available is ampicillin suspension 50mg/5ml.How many ml should the nurse administer per dose

[Cook26]

You were correct through the bolded. I assume the 25mg/kg PO is the daily dose. If so, then it needs to be divided by 2, not by 50 (since 1125 is daily dose, and it's being given BID).

They are correct through the entire thing, there is however one more step. The 112.5ml is the daily dose. Divide by two and you have the correct answer.

There are multiple ways to get to the correct answer.

[Anonymous865]

A nurse is preparing administer ampicillin 25 mg/kg PO divided in equal doses every 12 hrs to an adolescent who weighs 99 lbs.The amount available is ampicillin suspension 50mg/5ml.How many ml should the nurse administer per dose

Set up an equation

99 lbs x 0.454 kg/1 lbs x 25 mg/1 kg x 5ml/50 mg = ml /day

ml / day x 1 day / 2 doses = ml/dose

[KelRN215, BSN, RN]

Ok, I just gotta ask, what kind of adolescent is going to drink 56.25 mL of medication? (I do agree that that is the answer.) Ampicillin is available in 500 mg tablets, call the pharmacy to discuss dosing and then discuss the impracticability of administering this dose with the physician.