Dosage Calculations

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

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

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...

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

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.

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 My bad.

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.

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

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

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?

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

Openheartmom....thanks for the info..will be good for future ref. When my husband went to pharm class yesterday his prof said that after looking over the problems she realized that there wasn't enough information given????? She never looked over the info before giving it to the students. Anyway, thanks to all who responded...I don't feel so stupid now!