Understanding Equianalgesics

Daytonite, BSN, RN · May 10, 2006

i've never had to work with these and change dosages around before. i was able to find one instruction sheet as well as a pocket guideline that seems to have some instructions on it for changing between drugs. you can also access the opioid conversion tool on the johns hopkins site, but you have to register (it's free). looks like you would be able to play around with the converter and see what kind of drug equivalencies it gives you for various dosages of different opioids. if you are still having problems figuring these out, you might post on the cancer (oncology) nurses forum and see if someone there can help you out.

http://floridapain.org/instre2%7e.doc - an instruction sheet for making opioid equianalgesic conversion

http://sccpi.coh.org/pocketcard/2005/sccpi%20card.pdf - this is a pocket card of an equianalgesic chart with some guidelines about making conversions on it

http://www.hopweb.org/ - this is a opioid conversion tool from the cancer center of johns hopkins. you need to register to use it, but registration is free and you can input quite a number of opioids and their dose and it will give you alternative opioids and doses to use.

http://www2.mc.duke.edu/9200bmt/equianalgesia.htm - equianalgesic chart

AussieKylie · May 11, 2006

I need an understanding of how to work out ratios of parenteral medication to oral dose

eg: Codeine

Parenteral 130mg

Oral 200mg

Oxycodone

Parenteral 15mg

Oral 20-30mg

I will be happy if anyone can help me on this.

:confused: :paw:

CYR · May 11, 2006

I need an understanding of how to work out ratios of parenteral medication to oral dose
eg: Codeine
Parenteral 130mg
Oral 200mg

Oxycodone
Parenteral 15mg
Oral 20-30mg
I will be happy if anyone can help me on this.
:paw:

In what you've provided you already have a ratio. So if you are told either the oral or parenteral amount, you can then calculate the other. If you have say 75mg of parenteral Codeine and you want to know how this converts to oral amount? Set up your ratio as 130 over 200 (or the other way around; doesn't matter as long as you match your orals and parenterals) and this is equal to 75 over x (your unknown oral amount.) Now you cross-multiply 75 X 200 and divide by 130 and that is your oral amount when parenteral is 75mg. the answer would be 115mg of oral which makes sense when you look at it. Is this helpful or is your question something else?

AussieKylie · May 11, 2006

Thanks CYR

You have helped alot with the parenteral to oral conversion. I do understand the theory of it all, its the conversions that have stumped me. More practice and I will be a ok with it.

Um, may I also get your help and find out about medications that patients take orally and then go to IV. How to calculate the amount?

Thank you once again

:paw:

Daytonite, BSN, RN · May 11, 2006

I think some of that information was on the charts I gave you links to. Did you try the Johns Hopkins site to see if you could get this kind of information?

AussieKylie · May 12, 2006

Hi Daytonite

I did register for the hopkins site. I checked it out and was getting confused again.

:confused:

CYR · May 12, 2006

Hi confused down-unda

Its the exact same concept. If you are give the ratio between 2 different routes of medication and you are told the amount to be given for one of the routes but you want to know the other route, you set up the problem in the exact same way as I showed you. My college has a math lab with tutoring available...if you can get someone to tutor you and actually show you how to do these calculations I think that's better than having it typed out. Good luck!

AussieKylie · May 12, 2006

The confused part is on the hopkins site is that they show the calculation and it comes up with a conversion factor of 0.05 or 0.08 for parenteral and i am thinking a big HUH:confused: :chair:

It was going okay until I saw those conversion factors and wondering how it got that

Daytonite, BSN, RN · May 12, 2006

I really don't know anything about using these tables. Is there someone who works on an oncology unit that can help you with this? Perhaps a friendly doctor, an oncology nurse, or a pain specialist?

AudryC · May 12, 2006

In what you've provided you already have a ratio. So if you are told either the oral or parenteral amount, you can then calculate the other. If you have say 75mg of parenteral Codeine and you want to know how this converts to oral amount? Set up your ratio as 130 over 200 (or the other way around; doesn't matter as long as you match your orals and parenterals) and this is equal to 75 over x (your unknown oral amount.) Now you cross-multiply 75 X 200 and divide by 130 and that is your oral amount when parenteral is 75mg. the answer would be 115mg of oral which makes sense when you look at it. Is this helpful or is your question something else?

..As well, if you want to go more simple (as general rule) .. you know that for 1 mg oral Codeine ... you'll have 0,65 mg parenteral! Make this sens?

xxCheers

A.

Daytonite, BSN, RN · May 14, 2006

Found one more website that you might find helpful:

http://www.childcancerpain.org/content.cfm?content=pharm18