# Calculation

1. A desired dose for crystapen is 2.5 Mg, Q.i.d per 24 hours. If a drug on hand is 5iu.
Find the one dose

Joined: Nov '17; Posts: 5; Likes: 2

3. I am just curious who made up this question.
4. Quote from bjwojcik
I am just curious who made up this question.
This is so weird! I never had an IU question like this!!

I've never even heard of Crystapen? I looked it up and it says its benzylpenicillin:
Benzylpenicillin sodium (a derivative of Benzylpenicillin) is reported as an ingredient of Crystapen in the following countries:

• Malta
• United Kingdom

Is that correct? So, this isn't a brand in the U.S? Would this be Penicillin G Sodium in the U.S.?
Last edit by OneWhisper on Mar 15
5. I don't think this brand is available in the US. It is available in 600 mg vials which is equivalent to 1,000,000 units. That dose would be maybe appropriate for a grasshopper. Also, you would need to know how the 5 units was reconstituted. Just a dumb question that only served to cause confusion for the poor students.
6. Quote from bjwojcik
I don't think this brand is available in the US. It is available in 600 mg vials which is equivalent to 1,000,000 units. That dose would be maybe appropriate for a grasshopper. Also, you would need to know how the 5 units was reconstituted. Just a dumb question that only served to cause confusion for the poor students.
I don't think it is either. I found the 600 mg vial equivalent to 1,000,000 units and I did the calculations and came up with 0.003 mg as the answer. I then used the site Wuzzie gave and it gave the same thing that I came up with (0.003 mg). Not sure if that's right because this is definitely a dumb confusing question! I really wish instructors would try harder to make more REAL WORLD examples for students!
7. Well, the dose was 2.5 mg which is 4167 units or 833 of the 5 unit "on hand" vials, which does not make sense. The correct answer is 'Find one dose my a**. I will find one dose when you learn to write a dosage calculation problem that makes sense.
8. Thanks a lot