# drug computation.. help!

Published

The order is digoxin 0.325 mg and the stock is 0.25 mg/tab.. how many tab/s to give?

A. 2 tabs

B. 3

C. 1.5

D. 3/4

Per answer key the answer is 3/4 but no explanation. I want to know how did it come up to that answer. Tnx

The order is dilantin 5 mg/kg in a 50 lbs patient to be divided in 3 equal doses. Stock is 125 mg/ml. Waht is the current amt to be administered?

A. 3 ml

B. 2

C. 4

D 2.0

865 Posts

Specializes in Critical Care. Has 8 years experience.

Remember that the formula is dose ordered/dose on hand multiplied by volume/tabs.

So for number one you have .325mg/.250mg x 1 tab = 1.3 tab. Your book may have keyed that incorrectly. A way to check is see how much smaller or bigger your dose on hand is. In this case .250 is less than .325 so you know you're going to need at least 1 tab to get there.

Convert 50lbs to kg, 50lbs/2.2= 22.72. then multiple 5mg x 22.72= 113.75. Now you can continue with the formula, 113.75mg/125mg x 1ml = .91ml

844 Posts

I get 0.3mL for the second problem.

6 Posts

Hi okami i came up with the same answers but i'm just wondering why they are not included in the choices which makes me crazy like ___.

844 Posts

I am curious as to why you're getting 0.91mL for the second problem? If it's three divided doses wouldn't the admin amount be 0.3mL? (And it drives me crazy too when stuff is keyed wrong...though I understand things happen!)

3,833 Posts

Are you sure that you copied the questions correctly, as none of the answer choices you have provided are correct.

4,104 Posts

Specializes in NICU. Has 8 years experience.

I am assuming that the second problem should be 50 kg instead of 50 pounds. Unless your giving a pediatric patient Dilantin.

5 X 50= 250

250/ 125= 2mL per day

2/ 3= 0.67 mL

not one of the choices

4 Articles; 20,908 Posts

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma. Has 43 years experience.

You need to check the questions...I think you typed something wrong.

163 Posts

Specializes in Neuro Intensive Care. Has 1 years experience.

Yeah....... none of the given choices are correct. I hate it when that happens.

6 Posts

To everyone: yeah i made sure i copied it correctly. I was thinking about it and wonder why its none of the choices.. anyway thanks for your effort guys. At least i know i'm not the only one who came up with a different answer.

4 Articles; 20,908 Posts

Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma. Has 43 years experience.

As far as I am concerned the answers are not in the choices.....check with your instructor...if she says the answer is there let us know how she figured the problem.

Guests

Guest

0 Posts

OP, regardless of what choices appear and what the answer key says, the correct answers to the questions posed are as noted below. Any deviation from the answers that I've provided are either an error of transcription or an error of calculation.

Question 1: Answer = 1.5 tablets (as shown below)

[TABLE=width: 253]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]1 tab[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center]0.375 mg[/TD]

[TD=align: center]x[/TD]

[TD=align: center]----[/TD]

[TD=align: center]=[/TD]

[TD=align: center]1.5 tab[/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]0.25 mg[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[/TABLE]

Question 2: Answer = 0.9 mL (as shown below)

[TABLE=width: 244]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]1.0 kg[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center]50 lb[/TD]

[TD=align: center]x[/TD]

[TD=align: center]----[/TD]

[TD=align: center]=[/TD]

[TD=align: center]22.7 kg[/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]2.2 lb[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]5 mg[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center]22.7 kg[/TD]

[TD=align: center]x[/TD]

[TD=align: center]----[/TD]

[TD=align: center]=[/TD]

[TD=align: center]113.6 mg[/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]1.0 kg[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]1 mL[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[TR]

[TD=align: center]113.6 mg[/TD]

[TD=align: center]x[/TD]

[TD=align: center]----[/TD]

[TD=align: center]=[/TD]

[TD=align: center]0.9 mL[/TD]

[/TR]

[TR]

[TD=align: center][/TD]

[TD=align: center][/TD]

[TD=align: center]125 mg[/TD]

[TD=align: center][/TD]

[TD=align: center][/TD]

[/TR]

[/TABLE]

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