Unasyn dosing question

[shtinkypuppie]

Hello,

I am new to this site and am seeking some learned opinions on an issue that came up during a clinical rotation today.

I am a student nurse going through a pediatrics/obstetrics rotation at Harbor/UCLA Medical Center. I was caring for a young man S/P soft tissue injury who was recieving Unasyn 1gm IV Q6hrs. The order said, verbatim, "Unasyn 1gm IV Q6." As you doubtlessly know, Unasyn is an ampicillin/sulbactam combination. Pharmacy provided the Unasyn in a vial containing 1 gram Ampicillin and 500 mg sulbactam, making for a total of 1.5 grams of Unasyn. The drug guide reccomended that it be diluted in 3.2 ml of sterile water, making for a concentration of 250 mg Amp and 125 mg sulbactam per ml. When doing the calculations required by my instructor before administration, I calculated the amount to draw up to yield one gram of total medication, ampicillin and sulbactam combined. This neccessitated 2.666 ml to be drawn up. My instructor insisted that I calculate for one gram of total ampicillin activity, which required 4 ml to be drawn up (the entire vial). I doubted this, since the order was for 1 gm of UNASYN, not ampicillin, and giving the entire vial would really give 1.5 grams of Unasyn. Moreover, the amount that pharmacy reccomended I draw up agreed with my calculations perfectly: 2.666. When I asked an RN working on the floor, she said she agreed with me: draw up one gram of both medications.

Can anyone say which is the proper method? I still believe that prescribing one gram of Unasyn means one gram of both medications, not one gram of ampicillin.

Thank you for your time,

Eric

[meandragonbrett]

http://www.rxlist.com/cgi/generic2/unasyn_ids.htm

Check out this website and see if that gives you any answers.

[MiRnSoon]

I'm currently a inpatient hospital Pharm tech (about 5years now), soon to be RN student. Your calculation sounds correct to me. Combination drugs are usually only dosed upon one component. Unasyn being a combination drug, is only dosed upon the ampicillin component. One question I have for you, why didn't pharmacy prepare this?

[TazziRN, RN]

One question I have for you, why didn't pharmacy prepare this?

Some places, like mine, have nursing staff reconstituting meds.

[augigi, CNS]

If in doubt, you'd have to check with the prescribing physician as to his intention, but as ordered, you were correct. If he ordered 1g of the total preparation, you were exactly right.

I do think docs should order these combination drugs as the total amount of both components desired eg. 1g ampicillin/500mg sulbactam, rather than a trade name, for clarity.

[Antikigirl, ASN, RN]

WOW...I am so glad ours comes in already done by pharmacy! These IV bags have NS in them, then there is a vial of premixed on the top...you just fiddle around and pop the stopper (which is inside the bag...very easy) and shake it..done!

I love having a great pharmacy team! It has cut down errors tremendously!