need some calculation help

i was wondering if anyone could explain how to do these 2 types of problems to me. thanks

physician ordered gr. 1/200 of atropine. label reads gr. 1/100 per 1 ml.

how many mls would you administer?

and

. order: geopen 100 mg/kg im in 4 equally divided doses.

avail: 2 gm vial of geopen. add 4 ml of diluent to yield 1 gm/2.5 ml.

the patient weighs 66 lbs.

how many ml should you give at each dose?

the 1st one you know that gr 1/100 per 1 ml and you need gr 1/200 of atropine. so since the 100 is half of the 200 your going to give 2ml of the medication

for the 2nd one you have to convert the lbs to kg.. so they would be 30kgs

then you going to multiply 100mg by 30kg and get 3000.

the medicine is 1gm/2.5ml which is 1000mg/2.5ml.

you need to give 3000mg so if 1000mg is 2.5ml your going to have to give him 7.5ml total in the 4 doses. so you divide the 7.5 by 4 and get 1.875 ml so you round that to 1.88ml per dose

For the first problem why wouldn't it be 1/2 mL.

1/100 per 1 mL = 1/200 per x mL so x/100 = 1/200 then 200x = 100....x = 1/2

Am I thinking the wrong way on this one?

0.5 ml

The 1st one you know that gr 1/100 per 1 ml and you need gr 1/200 of atropine. So since the 100 is half of the 200 your going to give 2ml of the medication

100 is half of 200 yes when talking about WHOLE numbers. BUT we are talking 1/100ths and 1/200'ths..fractions

1/200 is less than 1/100 it is not double it. You'd give 0.50mL.

divide 1 by 100 you get 0.01

divide 1 by 200 you get 0.005

so you'd set it up 0.01/mL = 0.005/x

cross multiply to get 0.01x=0.005..isolate x, so you divide by 0.01

0.005 divided by 0.01 = 0.50mL

Physician ordered gr. 1/200 (0.005) of Atropine. Label reads gr. 1/100 (0.01) per 1 mL. How many mLs would you administer?

x = ([1/200] / [1/100]) * 1 mL

x = ([1/200] * [100/1]) * 1 mL

x = 100/200 * 1 mL

x = ½ * 1 mL

x = 0.5 mL

To clarify the steps, I have attached a word document in which all fractions in the formulas are expressed as fractions, rather than linearly.

I hope this information was helpful.

Atropine gr 1 200.doc

i agree, it should be 0.5ml for the first calc/

1/200=0.005

1/100=0.01

what you need is 0.005, what you have is .01/ml

0.01x = 0.005

x = 0.005/0.01

x = 0.5