Hi all

I am currently doing my Nurse prescribing and am looking at methadone - I have looked all over the net and am struggling to find a good resource that will explain the pharmacodynamics of methadone - i know it acts upon the opioid receptors ( primarily the mu opioid) but im struggling to find what happens from there - in depth - the only info im getting is the obvious effects ie resp depression etc but nothing saying HOW that actually happens - im also finding it hard to find info that says how it effects other neurotransmitters - ie seratonin, GABA etc

I have also found several articles with confilicting 'first pass metabolism'info some say methadone undergoes extensive first pass metablism and some say it doesnt hardly at all

please please can someone suggest either a web site ( or sites) or a decent book that explains all this

I have Rang - pharmacology but even that doesnt really explain what i need

Thanks

Hi my favourite read is Karch's Pathology of drug abuse by Steven B. Karch it's isbn number is isbn 0-8493-0343-5
It might be better to get it from a library as there is a new book out later this year.
This goes into good detail but I think i've some links at home I'll post them later.
Good luck with the course
Simon

quote:

Reply

I too am a fan of Karch. They have at least one copy at the Ian Smith drug reference Library in salford. I note you are from Lancs so this should not be too far away. They have a very helpful librarian called John Brooke who is a bit of a superstar.

Methadone pharmacology is very complicated. You can get a quick summary from the SPC ( summary of product charcteristics) but you can also look at Martindale - the complete drug reference. All hospital pharmacies keep a copy and many community pharmacies will too - I'm sure if you ask around someone will let you have a look at theirs - i doubt they will let you take it away though as it is a very large/expensive reference.

Hi

many thanks for your replies - they have a copy of Karch at my Uni library ( just searched online) i will pick it up tomorrow.
Simon - if you do have the links also i'd be very grateful

many thanks again

Jo,
Is this of use ?
http://opioids.com/overdose/index.html
There was also something on University of Dundee website but doesn't seem to be there anymore.
Karch is great ! I e -mailed him recently and got a reply. I understand he is doing some lectures in UK and also at IHRA conference.

Regarding the first pass metabolism Jo I'd put something like "compared to buprenorphine, methadone does not undergo extensive first pass metabolism and can therefore be taken orally, unlike buprenorphine which for the treatment of drug dependence needs to be taken sublingually". All of first pass metabolism is relative so by comparing it to the other commonly prescribed drug for opiate substitution nobody can criticise you.

Glad I didn't have to do anything like that when I did the prescribing course!

Simon - thanks the l;ink definately helped as did the Karch book - lol thats one HEAVY book!!!!
Nat - thanks for the idea - didnt think of that, a great way to get round saying exactly how first pass affects methadone

thanks all again

Jo,
Karch might be heavy but isn't it a great read?
I cannot wait for the new one with a chapter on Suboxone. I think some of it is hard going and needs another book to expalain what it means. It certainly gives me a thirst to learn more about finer points of how drugs work. I think reading it has given me a few Eureka moments.
How are yoy going with the course ?

I know this thread was some time ago but ...

I'm just coming to the end of my NMP course (I'm a pharmacist). I have found this resource really good - here's the link for all those who are interested.

http://www.painphysicianjournal.com/2008/march/2008;11;...4e3898e1b167697e8c33

I think it is great Rachel... and it colour too!