Dosage Calculations

DADENTY · Feb 6, 2006

ok guys need some help..my husband is going to CVT school and is taking a pharmacology class...here are the problems that are stumping us
Order is Levophed 22 cc/hr. drug factor is 0.53 mcg/min. How many mcg of Levophed is the pt getting per hr?
Order is Dopamine 4 (then the symbol is a 0 with a line thru it?). drug factor is 16.6 mcg/min. pt wt is 75 mg. the pump should be set at how many cc/hr?
If anyone can give us the formula we would be grateful! I am a med/surg nurse so I am not good with the ICU calculations and the pump would figure it out for me anyway :)....THanks!

The first equation. 22cc/hr = 22 mg/hr convert mg to mcg and divide by 60.

The second equation not sure, would have to look it up

sanchy · Feb 6, 2006

if you have 0.53 mcg in one minute how many would you have in 60? easy. 0.53 times sixty. There u go

bonesrn · Feb 6, 2006

sanchy...ok give us some credit, we get that but that is not the answer they are looking for. if I take 22 mg and convert to mcg would be 22 div by 1000 = 0.22 and divide that by 60 = .0037???? don't think that is correct but thanks for the info...

TopherSRN · Feb 6, 2006

22mg = 22000 Mcgs

If the first order is written correctly then the 22cc/hr is irrelevant if the order is for .53mcg/min.

.53 mcgs * 60mins (1 hr) = 31.8 mcg/hr

TopherSRN · Feb 6, 2006

Order is Dopamine 4 (then the symbol is a 0 with a line thru it?). drug factor is 16.6 mcg/min. pt wt is 75 mg. the pump should be set at how many cc/hr?

Just a guess. And im also just a student (with a penchant for CVI), but doesnt dopamine usually come 400mg to a 250ml bag? could the order also be 16.6 mcg/kg/min since a weight is given?

if the order is 16.6 mcg/kg/min then I'm getting 46cc/hr doing dimensional analysis. Im more than likely wrong :/

16.6mcg/kg/min * 75kg = 1245 mcg/mim

cc | 250cc 1mg 16.6mcg 60 min = 18,675,000 = 46 cc/hr

hr | 400mg 1000mcg 1min 1hr = 400,000 =

maybe someone else can post the right answer, assuming the above isn't it.

DADENTY · Feb 6, 2006

sanchy...ok give us some credit, we get that but that is not the answer they are looking for. if I take 22 mg and convert to mcg would be 22 div by 1000 = 0.22 and divide that by 60 = .0037???? don't think that is correct but thanks for the info...

Sorry Multiply by 60 :idea: My bad.

jimthorp · Feb 6, 2006

Order is Dopamine 4 (then the symbol is a 0 with a line thru it?). drug factor is 16.6 mcg/min. pt wt is 75 mg. the pump should be set at how many cc/hr?

This doesn't look like a complete order.

sanchy · Feb 6, 2006

why are you converting to miligrams when they want the answer in micrograms. maybe i got it wrong but thats the answer id give given the info in your problem. anyway good luck and if you find the answer let me know. ciao

outlierrn · Feb 6, 2006

I think Topher has it right on both problems, but I think the problems poorly worded. Never did like dimensional analysis, I always go with

dose desired/dose on hand X volume on hand

Larry

Indy, LPN, LVN · Feb 6, 2006

ok guys need some help..my husband is going to CVT school and is taking a pharmacology class...here are the problems that are stumping us
Order is Levophed 22 cc/hr. drug factor is 0.53 mcg/min. How many mcg of Levophed is the pt getting per hr?
Order is Dopamine 4 (then the symbol is a 0 with a line thru it?). drug factor is 16.6 mcg/min. pt wt is 75 mg. the pump should be set at how many cc/hr?
If anyone can give us the formula we would be grateful! I am a med/surg nurse so I am not good with the ICU calculations and the pump would figure it out for me anyway :)....THanks!

Something's seriously wrong with the second problem. The patient weighs 75 mg and is getting 16.6 mcg/min? So that's over 3 times the dose that is recommended for a one pound infant? Eek! And I thought zero with a line through it meant none. Maybe it's a typo?

openheartmom3 · Feb 6, 2006

quick drug calculations:

first find out the concentration of the bag/bottle of rx you are hanging:

mcg per cc = mg /cc x 1000 = concentration

*if the drug is delivered in mg then don't multiply by 1000

then to calc dosage for pt..follow this easy formula:

a) if you know the rate set on the pump but not the dose the pt is recieving use this formula:

rate x concentration/60 = mcg per min

(mcg/cc)

rate x concentration / 60 / kg = mcg per kg per min

(mcg/cc)

b) if you have an order to start a drip on a certain dose but don't know the rate then just turn the formulas around:

dose ordered x 60 / concentration = rate to set pump in mcg per min

(mcg/cc)

dose ordered x kg x 60 / concentration = rate in mcg per kg per min

example: dopamine ordered at 5mcg/kg/min..... bag comes with 400mg/250 pts weight is 75kg

find the concentration first by taking 400 / 250 x 1000 = 1600mcg/cc

now plug in the rest of the numbers:

5 (dose ordered) x 75 (kg) x 60 / 1600 = 14cc ( the rate to set the pump)

or you walk into your shift, see the pump set at 23cc......(still using the same concentration of dopamine and same pt wt @ 75)

23 x 1600 / 60 / 75 = 8.17 mcg/kg/min

hope this helps