Penicillin Reconstitution Help

[Amander]

Hello Everyone, 

I am having problems answering two questions regarding Penicillin Reconstitution and my professor is not answering my email. Can you please explain the problem and your reasoning behind the answer/mls used?

1. Order: Penicillin 700,000 units IM q4h.
The label on a five million unit vial contains the following reconstitution guide:
18.2 ml solution to make 250,000 units/ml
8.2 ml solution to make 500,000 units/ml
3.2 ml solution to make 1,000,000 units/ml
Circle the number of mls you will use to reconstitute the penicillin.

After mixing with this amount, how many mls should you withdraw from the vial in order to give and infant 700,000 units?

Answer: 700,000/1,000,000 x 1 ml = 0.7ml

2. Order: Penicillin 450,000 units IM q4h.
You find a 5 million unit vial with the following reconstitution guide:
18.2 ml solution to make 250,000 units/ml
8.2 ml solution to make 500,000 units/ml
3.2 ml solution to make 1,000,000 units/ml

After reconstituting, how many mls should you withdraw in order to give 450,000 units?

Answer: Use the 3.2 ml solution
450,000 units/ 1,000,000 units x 1 ml = 0.45 ml

I am seriously struggling with these questions and I appreciate any assistance received. 

[chare]

2 hours ago, Amander said:

[...]

I am seriously struggling with these questions and I appreciate any assistance received. 

Are you having difficulty with the reconstitution, the calculation, or both?

And, did you calculate the answers included in the post, or were they provided to you?

[Amander]

The answers were provided by my prof but she did not explain how she came to the conclusion that she did. I guess I am having problems with the reconstitution? I am trying to figure out how the certain ml was chosen for reconstitution. Once I get the ml I understand how to do the math it is just selecting the correct ml is what I am having problems with. Thank you so much Chare

[amoLucia]

Re reconstitution - think about it. But don't OVERthink it. NOT rocket science!

INFANT and IM injection. You want the SMALLEST volume to use to mix your soln. You then give a small volume injection dose to an itty-bitty body. (They still use thigh muscles as primary inj sites, yes?) 

If you were administering the med IV, you'd still prob want a small amt of drug (incl IV fluids). You certainly wouldn't want to fluid-over load the itty-bitty.

If your pt were an adult, you'd have some more reconstituting wiggle-room. For an adult, your inj would be in the deltoid or butt muscle. More accepting.

Some times, the simplest, most obvious answer is just staring at you!  ?

[Amander]

THANK YOU SO MUCH! When I tell you, you just saved my sanity you did. Okay, so the reason why those are the answers is because we want to administer the lowest ml? Thank you so much, I was racking my brain why I couldnt understand it. Thank you so much, I seriously cant thank you enough ❤️ 

[amoLucia]

Like I said, if it got any more simple, it would bite you.

Real critical-thinking  ;))

[Amander]

Thank you so much, I completely agree LOL. I hope you enjoy the rest of you day and thank you again ?

[Abkr80]

Remember you are dealing with units per ml. So 3.2 ml makes 1000000u/ml 

you want 700000u 

one ml is 1000000 units  so divide 1000000/700000 units = 0.07 ml 
 

[Abkr80]

Just remember 3.2 milliliters makes 1000000 units PER 1 milliliter 

 

I think that’s where you are getting hung up