Professors and R. Nurses. How to do dosage calculations and conversions in dosage calculations?

Question

Example: 2.5g Doctor order 750 mg/ tablet drug available. How many tablets to give?

.025mg Doctors orders 50 mcg/ tablet drug available. How many tablets to give?

100 mg Doctor ordered 200mg/tsp. drug available. How many ML to give?

0.65g Doctors orders 225 mg/ Tablet drug available. How many tablets you give?

Those are some of the questions I am getting, I just cant figure out how to come out with the correct answer. I will appreciated if any one can teach me an easy way in how to resolve this calculations or any others.

Hi Thanks for your answer. I am a student to become an RN and this are the questions we are getting in our test, so as a R.nurse we are suppose to know this calculations i just thought there have to be an easier way to resolve the calculations...without the pharmacist assitance. :)
But now I know how they do in hospitals that is a relieve.

Answer 1

Actually Sybil's answer isn't entirely correct.
Legally a nurse is still responsible for giving the incorrect dosage of a drug even if the pharmacist or physician figured out the dosage.
A nurse has to know how to calculate to double check that they are giving the right dose.
There are also times when a nurse has to calculate because some meds are mixed or drawn up at the bedside.
So it's not 100% true that the pharmacists are responsible for it.

Answer 2

I'm not a doctor, RN or a professor. I'm a pharmacy tech and I do this everyday. The rule of thumb is that you always give the closest does as long as it is lower than the desired does:

2.5g ordered, 750mg tab available: to get the exact does you have to give 3.333 tabs which is impossible. So you go with 3 tabs.

0.025mg ordered and 50mcg tab available:
1mg =1000mcg
0.025mg = x mcg
x = 250mcg
So you give 5 tablet

100mg ordered, 200mg/ teaspoon available, give 1/2 teaspoonful which is 2.5ml

0.65g ordered 225mg tab available:
0.65g = 650 mg
650/225 = 2.888888 you can either give 2 and 3/4 tablet for a total of 618.75mg or ask a doctor for a does change to 675mg and give 3 tabs if possible.

Answer 3

Actually, when a Dr. dispenses this, the Pharmarcist figures it out. Not the nurse. We can, but, we don't have to. The guy behind the counter at the Pharmacy is responsible to give the correct doseage, Not the RN's. ~~~~

Answer 4

Nursechick is right. Never forget, you are the last line of defense for your patient. It is your responsibility to catch everyone elses mistakes before they make it to your patient and speak up to prevent them from happening. Good nurses always advocate for their patients, even if it means calling out someone elses mistakes.