Gawd, I feel stupid. Here's my problem:

I have 250mg of the drug Cytoxan, and I add 50mL of solution to it. The question is, How many mL will be dispensed per dose?

The answer is 12.5 mL. How the heck do you get that???

Check that...I have 1g total of Cytoxan and the prescription calls for 250mg of it once a day for 5 days.

Gawd, I feel stupid. Here's my problem:

I have 250mg of the drug Cytoxan, and I add 50mL of solution to it. The question is, How many mL will be dispensed per dose?

The answer is 12.5 mL. How the heck do you get that???



I have no idea. I got 10.5 mL. :confused:

I got 0.0022 something...I dunno, way off. :lol:

Are you sure the perscription isn't for 4 days? Because 50 mL/4 = 12.5

Plus, 1 gram isn't enough for 5 days of 250 mg, you'd need 1.25 grams for 5 days, or 1 gram for 4 days...or something like that.

It says 5 days. Cytoxan 250mg IV qd x 5 days. Of course, that doesn't mean it's not wrong. This worksheet is kind of stupid anyway.

Are you sure the perscription isn't for 4 days? Because 50 mL/4 = 12.5

Plus, 1 gram isn't enough for 5 days of 250 mg, you'd need 1.25 grams for 5 days, or 1 gram for 4 days...or something like that.

I thought you were supposed to convert the mg to mL then add 50 mL. :confused:

1 mL=100 mg

I thought you were supposed to convert the mg to mL then add 50 mL. :confused:

1 mL=100 mg

Hmm, well I just figured it was wondering how much solution was dispensed per dose of the drug, in mL, in which case converting isn't necessary..I could be wrong.

I thought you were supposed to convert the mg to mL then add 50 mL. :confused:

1 mL=100 mg

I looked all over the net for that conversion!

I'm thinking I'm not going to work in a hospital pharmacy. :lol:

I thought you were supposed to convert the mg to mL then add 50 mL. :confused:

1 mL=100 mg

So that would be 2.5mL=250mg, right? Then add 50mL and get 52.5mL. Then I get 10.5 like you. For four days, it's 13.something.

Stupid problem. How did I ever pass trig?

What little math skills I once had vanished a long time ago. :lol:

What little math skills I once had vanished a long time ago. :lol:

Apparently mine have too. :lol: My rule for math in HS was always, once the final was over, I forgot everything the minute I walked out the door.

I looked all over the net for that conversion!

I'm thinking I'm not going to work in a hospital pharmacy. :lol:

Well, I could be completely wrong too. lol Math isn't my strong point either.

Hmm, well I just figured it was wondering how much solution was dispensed per dose of the drug, in mL, in which case converting isn't necessary..I could be wrong.

That's what it's asking, but you still need to convert if the 250 mg is taken into account for the solution of the problem. If it isn't, the answer is 10 mL. There's probably some really weird way to solve the problem that we haven't figured out yet. This is going to drive me insane. :lol:

Edited: The 1 mL= 100 mg conversion is if you're measuring water. The conversion is different for every substance. :rolleyes:

That's what it's asking, but you still need to convert if the 250 mg is taken into account for the solution of the problem. If it isn't, the answer is 10 mL. There's probably some really weird way to solve the problem that we haven't figured out yet. This is going to drive me insane. :lol:

Edited: The 1 mL= 100 mg conversion is if you're measuring water. The conversion is different for every substance. :rolleyes:

Oh great...no wonder I couldn't find anything! :lol:

I know what you mean. I hate when stupid little problems like this defeat me.

Are you in pharmacy school or something?

That's what it's asking, but you still need to convert if the 250 mg is taken into account for the solution of the problem. If it isn't, the answer is 10 mL. There's probably some really weird way to solve the problem that we haven't figured out yet. This is going to drive me insane. :lol:

Edited: The 1 mL= 100 mg conversion is if you're measuring water. The conversion is different for every substance. :rolleyes:
it would actually be more complicated than that because the solid is dissolved into the liquid solution - which would change the volume by an unknown amount (unless you know a lot more about chemistry than you are letting on)

the question is, AFTER you add the 250g to the 50ml of solution, how many ml do you have?

of course, either way you look at it, unless the mixture gives you 62.5ml total volume, you would appear to only have a 4 day dose; 1g divided by 250mg per day = 4 days, and 50ml divided by 4 days = 12.5ml

it would actually be more complicated than that because the solid is dissolved into the liquid solution - which would change the volume by an unknown amount (unless you know a lot more about chemistry than you are letting on)

the question is, AFTER you add the 250g to the 50ml of solution, how many ml do you have?



It's 50 mg. Don't you have to convert the 250mg to mL though?

It's 50 mg. Don't you have to convert the 250mg to mL though?
no - you CAN measure the volume of the 50mg (ml is a measure of volume, whereas mg is a measure of weight) - but it is irrelevant because it is dissolved into the solution anyways

when you add the solid to the liquid it will change the total volume, but its like adding salt to water - the water will absorb a certain percentage of the salt before it starts settling at the bottom, adding to the total volume.

*** in this case the amount of solution doesnt matter - you are dispensing a certain amount of the drug, 250mg per day. If you have 1 gram total you still only have a 4 days dosage.

if you mix the drug and the solution together, you would measure the total volume, and whatever it is, you would have to divide it by 4.

no - you CAN measure the volume of the 50mg (ml is a measure of volume, whereas mg is a measure of weight) - but it is irrelevant because it is dissolved into the solution anyways

when you add the solid to the liquid it will change the total volume, but its like adding salt to water - the water will absorb a certain percentage of the salt before it starts settling at the bottom, adding to the total volume.

How do you work the problem then? :confused: Also, grams measure mass, but that's not important lol.The question asks for a 5 day dosage. What is the amount of the total liquid solution?

How do you work the problem then? :confused: Also, grams measure mass, but that's not important lol.

weight and mass are pretty much the same thing (as long as gravity is constant)

you are thinking about it too hard - to calculate it the way you are trying to, you would have to know the density of the drug (how many ml of drug are there per gram) and multiply that by the weight (alright mass then) of the drug, then you would need to know the solubility of the drug in the solution (how much of it will be absorbed by the solution before it increases the total volume).

it would be far easier to just measure it.

How would you measure it though? Wouldn't you get the same solution if you did the conversion?

Oh................ Math and I have never gotten along! When my son was learning fractions( way back when )I had completely forgotten how to do them! Well, In helping him , I relearned fractions. It was sad! You snooze, you lose! :crazy:

How would you measure it though?
measuring cup, measuring spoons, graduated cylinder, laser-guided turkey baster - it don't matter

Wouldn't you get the same solution if you did the conversion? maybe - if you were VERY careful, and had a way to accurately make those conversions...but your margin of error would probably be higher than the quantities involved

measuring cup, measuring spoons, graduated cylinder, laser-guided turkey baster - it don't matter

I meant in this instance. Didn't Dawsongirl say the problem was from a worksheet?

I meant in this instance. Didn't Dawsongirl say the problem was from a worksheet?
i dont think so, but in this case, they do not provide you enough information to calculate an answer mathematically.

i dont think so, but in this case, they do not provide you enough information to calculate an answer mathematically.
beyond the simple

1 gram divided by 250mg = 4

and

50ml divided by 4 equals 12.5ml

Are you in pharmacy school or something?

Pharmacy Technician school. That's why I'm not too worried that this one problem seems screwed up, cuz I'm not going to be a full out pharmacist.

lol...I'm either making this problem too hard in my head, or I'm just plain lost.

I'm declaring the question wrong and burning it.

lol...I'm either making this problem too hard in my head, or I'm just plain lost.

I'm declaring the question wrong and burning it.
Sounds like a good idea to me. :lol:

I know what you mean about forgetting how to do simple math! These days were all so spoiled by using calculators. Just a few weeks ago my mom and I were at the bank and I had to either divide some number or do long division and I had no clue how to do that! I ALWAYS use a calculator!