Pediatric Dosage Calculations

[nksando]

I am starting my Peds rotation next Monday and in advance we have some dosage calculations to complete prior to our first clinical day. I am having really hard time understanding how do calculate reconsituted meds. Could someone please help with some guidance? I checked the math thread but couldn't find help and the tutorial in my syllabus does a poor job at showing step by step how to get the answers. So for all you dosage math whizzes could you please help:

The patient is an 18-month old boy, weighing 22 pounds. The medication order is "600 mg of ticarcillin I.V. every 6 hours in D5NS.

The direction on the drug bottle says: "To reconstitute, add 4.2 ml of sterile water for injection. The resulting solution will equal 1 gram/5ml of ticarcillin. Refridgerated ticarcillin is stable for 24 hours"

1. How many ml of the reconstituted drug would you have to administer for the patient to receive the 600 mg ordered?

2. How many ml of the I.V. solution (volume to be infused) are needed to administer the desired dose of 600 mg of ticarcillin in a 50mg/ml concentration:

If anyone could help I would very much appreciate it. Thanks!

[Daytonite, BSN, RN]

the patient is an 18-month old boy, weighing 22 pounds. the medication order is "600 mg of ticarcillin i.v. every 6 hours in d5ns.

the direction on the drug bottle says: "to reconstitute, add 4.2 ml of sterile water for injection. the resulting solution will equal 1 gram/5ml of ticarcillin. refridgerated ticarcillin is stable for 24 hours"

1. how many ml of the reconstituted drug would you have to administer for the patient to receive the 600 mg ordered?

dose desired:

600 mg

dose on hand:

1 gram/5 ml

600 mg

(dose desired)

/1 gram

(dose on hand)

x 5 ml

(amount the dose on hand comes in)

/1 x 1 gram/1000 mg

(conversion factor)

=

3 ml

(amount to give)

2. how many ml of the i.v. solution (volume to be infused) are needed to administer the desired dose of 600 mg of ticarcillin in a 50mg/ml concentration?

if there are 50 mg of ticarcillin/ml of iv solution, then how many ml of iv solution will have 600 mg of ticarcillin?

50 mg/1 ml = 600 mg/

x

ml

so, 50

x

= 600

x

= 12

600 mg/12 ml of iv solution

[nksando]

Thanks so much Daytonite. I was complicating the whole equation when I set it up. I was trying to use the 4.2ml that was listed in the problem when I didn't even need it at all.

Thanks again!