Hello everyone!I've been up and racking my brain trying to solve this problem. and im almost getting dizzy. im really bummed out about this bc none of my answers make sense. I would like some help solving this problem please !!Order: Erythromycin 750mg in 250 mL NS over 2 hoursAvailable: erythromycin 1g powdered vial, reconstitute with 20 mL sterile water for 50mg/mLuse a 15 gtt/mL set . Calculate your drops per minute (gtt/min)ANY help is appreciated :) Edited Feb 10, 2016 by blackout156 0 Likes

cracklingkraken, ASN, RN 1,855 Posts Feb 10, 2016 What have you tried doing? Where are you stuck? 0 Likes

blackout156 4 Posts Feb 10, 2016 I did this 750mg x 1ml/50mg= 15mL x 15gtt/mL = 225gtt then divided 225gtt by 60min and that gives me 3.75 or 4gtt/minim not sure if thats correct but it looks like it isand also the 750mg in 250 mL NS and Erythromycin 1g available are numbers that are throwing me off and im not sure if they are supposed to be included somewhere in my equation 0 Likes

Emmalynn 26 Posts Feb 10, 2016 The formula is mL/hr X gtts/ml divided by 60 so it would be (125)(15)/601875/6031.2531 gtts/minI just finished my dosage calculations class and my professor was very strict about finding the hourly rate ALWAYS when doing these types of problems because that's what you have to put in the pumpAlso they put a lot of extra info into these problems that isn't really relevant 0 Likes

SilleLu Has 3 years experience. 150 Posts Feb 10, 2016 (total volume to infuse x drip factor)/total minutes to infuse = gtt/minHint: You do need to do an additional calculation to get the total volume 0 Likes

blackout156 4 Posts Feb 10, 2016 750mg x 1mL/50mg = 15mlthen 15mL + 250 mL NS = 265mL265mL x drip factor/total minutes to infuse (265mL x 15gtt/mL)/ 120 min = 33.1so, 33gtt/mincan anybody check if im correct? 0 Likes

Mavrick, BSN, RN Specializes in 15 years in ICU, 22 years in PACU. Has 30 years experience. 1,578 Posts Feb 12, 2016 Where are you getting the 250 NS? If it is a 250ml bag there is always a bit of overfill, so calculating the additional 15ml of reconstituted Erythromycin is really only necessary for school problems. In which case you would withdraw 15 ml of NS before adding the 15 ml of Erythromycin.As if 33 vs 31 gtts/min is significant. 0 Likes

Mavrick, BSN, RN Specializes in 15 years in ICU, 22 years in PACU. Has 30 years experience. 1,578 Posts Feb 12, 2016 The formula is mL/hr X gtts/ml divided by 60 so it would be (125)(15)/601875/6031.2531 gtts/minI just finished my dosage calculations class and my professor was very strict about finding the hourly rate ALWAYS when doing these types of problems because that's what you have to put in the pumpAlso they put a lot of extra info into these problems that isn't really relevantExactly! In this case the Erythromycin calculation isn't even necessary. Just calculate how to run 250ml over 2 hours. 0 Likes