Math Again

1 I'm doing some practice problems, and this is from nursesaregreat.com:
A procainamide drip is ordered (2 gm in 250 cc of D5W) to infuse at 4mg/kg/min. The patient weighs 165 lbs. Calculate the drip rate in cc/hr for which the infusion pump will be set at.
165 lbs = 75 kg
2gm = 200,000 mcg
4mg = .004 mcg
I'm trying to do the formula like this:
solution cc
__________ X 60min/hr X kg X mcg/kg/min = cc/hr
drug mcg
Am I doing this right? The answer should be 30, but that's not what I'm getting. I'm sort of hoping this problem has a mistake in it because it has fried my brain! I did, however, catch the preposition at the end of the sentence, so maybe I should have majored in English. 


0Jan 22, '12 by jmdRN4mg = .004 mcg
4 MILIgrams (mg) = 4000 MICROgrams (mcg)
And.. why are you working it down to mcg when the question is asking for mg/kg/min?
Is it really suggesting you run it at 4mg/kg/min (which is a very HIGH dose) or did you have a typo there?
When you break down numbers/values to smallerthanrequired values, you introduce a greater risk of decimal place errors.Last edit by jmdRN on Jan 22, '12 
0Jan 22, '12 by JROregon, ASN, BSNI keep getting 2250 cc/hr.
300 mg/min (amt needed)
______________________ X 250 cc = 3.75 cc/min X 60 = 2250 cc/hr
2000 mg (amt you have)
By the way, 2 grams = 2,000,000 mcg. 
0Jan 22, '12 by Esme12, ASN, BSN, RN Senior ModeratorProcainamide is administered intravenously or orally. When administered intravenously, a loading dose should first be given, though care should be taken not to cause hypotension. Procainamide's major active metabolite is Nacetyl procainamide (NAPA), which is approximately equipotent with the parent drug as an antiarrhythmic agent. NAPA has an elimination halflife about twice that of procainamide, and it can reach somewhat higher plasma levels during chronic procainamide administration. Loading dose is 100 mg IV bolus given slowly over 5 minutes. Max dose is 17 mg/kg. Use is discontinued when dysrhythmia is suppressed, or if hypotension ensues, QRS complex widens by 50% or more, or maximum dose is achieved.
Now the math.....you will find these very valuable
DosageHelp.com  Helping Nursing Students Learn Dosage Calculations
http://www.davesems.com/files/drug_d...lculations.pdf 
0Jan 22, '12 by JROregon, ASN, BSNI like dosagehelp.com. Simplifies the questions. Like jmdRN says don't "over" convert your grams and milligrams. If you have a problem with both mg and gm, just convert one to the other. When you are taking a test, make sure that you remember which is a larger mass. If you have 1 gram of something, it's going to be 1,000,000 mcg. I think you found a problem with a typo.

0Jan 22, '12 by KelRN215, BSN, RNWell, in your problem, you say the dose is in mg/kg/min and then you're trying to work out the answer in mcg/kg/min. So there's problem #1. 4 mg/kg/min seems like an extremely high dose of procainamide... 300 mg/min? Seems unlikely.

0Jan 22, '12 by RNrerunWow. Thanks for all the help. I'm going to assume there's something wrong with this problem. I'm trying to relearn all these calculations that I haven't done in years and years, and it doesn't take much to confuse me. I have been using dosagehelp.com to practice, and I'll check out the other one that Esmel reccommended. I'll have to take a medications test at the hospital, and I'm trying to get all this straight in my head before I go in there!
Thanks! 
0Feb 18, '13 by lethomson91Quote from RNrerunThere's nothing wrong with the problem.Wow. Thanks for all the help. I'm going to assume there's something wrong with this problem. I'm trying to relearn all these calculations that I haven't done in years and years, and it doesn't take much to confuse me. I have been using dosagehelp.com to practice, and I'll check out the other one that Esmel reccommended. I'll have to take a medications test at the hospital, and I'm trying to get all this straight in my head before I go in there!
Thanks!
In this case, the patient's weight is irrelevant  it doesn't impact the dose, so it's simply left out.
dose ordered = 2 g in 250 cc (cc = mL)
infusion rate = 4mg/min
4mg/min x 250mL/2g x 1g/1000mg x 60min/hr = 30 mL/hr 
1Feb 19, '13 by Esme12, ASN, BSN, RN Senior ModeratorQuote from lethomson91The thread is over a year old....and I beg to differ.......the weight IS relevant.....There's nothing wrong with the problem.
In this case, the patient's weight is irrelevant  it doesn't impact the dose, so it's simply left out.
dose ordered = 2 g in 250 cc (cc = mL)
infusion rate = 4mg/min
4mg/min x 250mL/2g x 1g/1000mg x 60min/hr = 30 mL/hr
A procainamide drip is ordered (2 gm in 250 cc of D5W) to infuse at 4mg/kg/min. The patient weighs 165 lbs. Calculate the drip rate in cc/hr for which the infusion pump will be set at.
This math question is all about the weight.KelRN215 likes this.