new nurse! need help with some dosage calculations

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Would love some help with any or all of the following questions from a practice medication test....

1.) A patient is transferred from another hospital on a Nitro gtt (50 mg in 500 ml D5W). The gtt is infusing at 8 ml/hr. How many mcg/min of Nitro is the patient receiving?

Hint: the drug constant for this concentration of Nitro is 1.67.

Must show all work.

2.) What is the drug constant for Dopamine 400 mg in 250 ml of D5W?

3.) The doctor orders you to start a Dopamine gtt at 5 mcg/kg/min on a patient that weighs 163 lbs. How many ml/hr would you infuse?

Must show all work.

4.) The drug constant for Dobutamine is 33.34. What would the patient constant be for a 138 lb. patient?

Must show all work.

5.)The order is to give 2 mg of Rocephin in 100 ml of NS over 45 minutes. What is the infusion rate in ml/hr?

Must show all work.

6.) You have an order to give 500 ml of D51/2 NS over a 12 hour period. You are using 15 gtt/ml tubing. The hospital has no available IV pumps. What should the drip rate be in gtt/min?

Must show all work.

7.) The order is to give 0.15 mg of medication. The dosage strength available is 200 mg/ml. How many ml do you give?

Must show all work.

8.) Dramamine 35 mg is ordered. You have Dramamine 50 mg/cc. How many cc do you give?

Must show all work.

9.)80mg Solu-Medrol is ordered. You have a vial which contains 125 mg in 2 cc. How many cc's do yo give?

Must show all work.

10.) About the drug Amiodarone. Which of the two following descriptions would be most appropriate for this drugs' uses. 1-Indicated for VF/pulseless VT. Also used for stable VT, wide complex tachycardias of uncertain type, wide-comples PSVT. (Class IIb).

or 2-Used in a wide variety of atrial and ventricular tachyarrhythmias and for rate control of rapid atrial arrhythmias in patients with impaired LV function when digoxin has proven ineffective.

1 or 2?

Any help is much appreciated!

Still learning, Katyj:balloons:

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you can teach me something, what does the term "drug constant" mean?....and #7 doesnt appear to be a reasonable question, are you sure the decimals are in the right places and/or are the units of measure correct?

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Specializes in icu, er.

dear new nurse::welcome:

two formulas will serve you well to get drip answers. There are bunches out there so to avoid confusion pick and stick to one way. here's one I like: don't get discouraged.

FIRST: you must know the concentration per solution: (see below)

CONCENTRATION PER SOLUTION FORMULA:

It's dopamine: you understand that dopamine runs at mcq/kg/min so,

look at the bag of dopamine. at 400mg in 250 cc here is the

formula for concentration per solution:

400 x 1000 (to make it into mcq now)

= 4000/250 cc per solution = 1600 mcq per solution.

this 1600 must be plugged into the formula.

NOW we can start to figure either the RATE or the DOSE.

(you will see it's really just one formula tweeked)

facts: pt weight 65 kg.

there are 60 minutes in one hour.

the offgoing RN told you the drip is running at 7 mcq(kg/min).

The gtt is running at 17 cc/h.

Is she correct? Lets find out.

RATE: 7 x 60 x 65 /1600 = 17 ? yes (see facts to plug in numbers)

DOSE: 17 / 60 / 65 x 1600 = 7? yes

:idea: If your drug runs at mcq/min - just leave out the kg. If your drug runs at mg/min just don't change it into mcq. If it runs at mg/hour, just use a 1 (for one hour) instead of 60 (for 60 minutes).

hope this helps.

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#7 is as appears on my pre-test. As for a constant, the only definition in Mosby's I found was "one that remains the same, unchanged". I didn't learn this one in Pharm math.............how about any of the others?

Thanks!

you can teach me something, what does the term "drug constant" mean?....and #7 doesnt appear to be a reasonable question, are you sure the decimals are in the right places and/or are the units of measure correct?
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yes, I am blonde but..........which one is the drug constant? This was all for the same problem correct? number 2 on my original posting?

Thanks!

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#7 is as appears on my pre-test. As for a constant, the only definition in Mosby's I found was "one that remains the same, unchanged". I didn't learn this one in Pharm math.............how about any of the others?

Thanks!

#7 works out to be0.00075 ml.......unless you dilute and remeasure?

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Specializes in icu, er.

I think what is meant by the contstant factor is the "C" factor.

also known as the "X" factor.

if so it goes like this:

using dopamine again...400 mg in 250 cc

(and dopamine runs at mcq/kg/min.)

400 x 1000 (because must change mg to mcq because this is the way dopamine is supposed to infuse AND you can change mg to mcq by x 1000.) = 400,000

400,000 / 250 cc = 1600 (again we have solved 1st for the concentration of the solution.)

1600 / 60 (minutes in one hour because it runs in "min") = 26.6666666.

26.666666 / 65 kg (that's the pt weight) = 0.41

NOW...0.41 is our x factor or c factor whatever you want to call it.

what's great about having the x factor is that you take it and x it by the cc running in your iv...say it's 15 cc.

0.41 x 15 cc = 6.15. that means the gtt is running at 6.2 mcq/kg/min.

if it is running at 20 cc hour that is: 0.41 x 20 = 8.2 mcq/kg/min.

regards,

trish

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Specializes in Diabetes ED, (CDE), CCU, Pulmonary/HIV.
Would love some help with any or all of the following questions from a practice medication test....

1.) A patient is transferred from another hospital on a Nitro gtt (50 mg in 500 ml D5W). The gtt is infusing at 8 ml/hr. How many mcg/min of Nitro is the patient receiving?

Hint: the drug constant for this concentration of Nitro is 1.67.

Must show all work.

2.) What is the drug constant for Dopamine 400 mg in 250 ml of D5W?

3.) The doctor orders you to start a Dopamine gtt at 5 mcg/kg/min on a patient that weighs 163 lbs. How many ml/hr would you infuse?

Must show all work.

4.) The drug constant for Dobutamine is 33.34. What would the patient constant be for a 138 lb. patient?

Must show all work.

I've never heard the terms "drug constant" and "pt constant" but from what I see above, drug constant must be the amt of drug deliverered per unit of volume or per unit of time. The nitro is 1.67 mcg/min.

The drug constant for the dopamine 400mg/250 ml would be 26.67. (26.67 mcg/min). If the pt weighed 65 kg as in tpk66's example, pt constant would be 0.41 as shown in her example. If pt weighed 74 kg (162.8 or about 163 lbs) as in # 3, the pt constant would change (26.67/74). But pt constant would change if pt's wt changed--so not sure how constant that would be--especially in pt with CHF.

Then based on this, pt constant for #4 would be 33.34/63 kg - 0.53

Of course, I'm just thinking out loud. I've always used factor labeling and do each calculation individually.

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