[CARPA] Fwd: Re: swapping to Metformin XR

[Mark Dunn]

Hi Fran

There has been some discussion on the on AusPharmList recently

May I post your comments below?

I'll make sure the post gives the CARPA list a plug

Cheers...............Mark

At 11:27 AM 19/04/2007, you wrote:
>The pharmacokinetics of metformin is tricky. Metformin is absorbed in
>the upper GI tract and is water soluble making it hard to release the
>drug slowly in a XR form and to keep it in the right place long enough
>to release and be absorbed.
>
>Thus it was necessary to formulate it into a polymer that forms a
>gelatinous mass in the stomach. The size of this mass, a concurrent meal
>and the natural diurnal slowing of the GI tract at night together
>provide the best conditions for absorption because of delayed passing
>through the gut. There is also a saturation effect with doses greater
>than 2g not having a proportional increase in absorption. One also
>wonders about the impact of 6 "gelatenous masses" in the gut at the same
>time?
>
>All the trials on the XR formulation were done with dosing with the
>evening meal and I have wondered by how much this is reduced in reality
>if given with a morning meal. And whether a reduction in absorption is
>more than offset by an increase in compliance. In other words, is
>morning metformin XR 2g better than morning regular metformin 1g (the
>evening dose being forgotten?).
>
>I'd be interested to hear if there are actual clinical benefits like
>lower HbA1cs in your patients?
>
>The other issue is one of side effects. Having a smaller amount of drug
>released into solution in the gut at any one time might logically be
>associated with less GI side effects. The trials showed no difference
>between XR and regular metformin but the numbers were low. Has anyone
>noticed an impact on GI side effects?
>
>Fran Vaughan
>Pharmacist
>
> >>> <MichaelW.Nixon at nt.gov.au> 19/04/2007 9:24 am >>>
>I am finding such a lot of non-compliance amongst the Aboriginal
>diabetic
>population and I'm slowly changing all my patients over to SR metformin
>
>(up to 2gms) in the hope that there may be more compliance by a once
>daily
>dose in the morning - to be had with their weetbix or porridge! - So
>far
>seems to be working. Just watch the Kidneys! - Mike.
>
>Dr Michael W Nixon
>DMO Reg.  Rm 126,  Block 4, RDH
>(Chair MSHR, Ethics Research Committee)
>Box 40596
>CASUARINA NT 0811
>Ph 892 28358 Mob 0427 618 915
>
>
>
>
>"Alex Hope" <wombat at octa4.net.au>
>Sent by: carpa-bounces at ozdocit.org
>18/04/2007 09:36 PM
>Please respond to
>Central Australian Rural Practitioners Association <carpa at ozdocit.org>
>
>
>To
>carpa at ozdocit.org
>cc
>
>Subject
>[CARPA] Fwd: Re: swapping to Metformin XR
>
>
>
>
>
>
>Would be good to have input from a few more people on this topic.
>I haven't tried it with any of my patients yet.
>Alex
>(scroll down for email exchange)
>Dr Alex Hope
>
>Community GP,
>Ltyentye Apurte Community Government Council Health Centre,
>CMB Santa Teresa,
>via Alice Springs,
>NT 0872.
>
>Ph  08 8956 0911
>Fax 08 8956 0910
>Mobile 0408 085 143
>
>
>
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>
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>
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>
>***********Here Followeth a  Forwarded Message***********
>
>On 18/04/2007 at 8:18 PM Ciara.OSullivan at nt.gov.au
><Ciara.OSullivan at nt.gov.au> wrote:
>
> >Hi there
> >
> >The recommended maximum dose of metformin XR is 2 g daily, which is
>pretty
> >much in line with the total dose of standard metformin we are mostly
>using
> >now.
> >
> >Ideally metformin XR is taken nocte ... but this is not very practical
>
>and
> >I think we just have to compromise over this detail.
> >
> >Cheers - Ciara
> >
> >-----Christine Connors/THS/NTG wrote: -----
> >
> >To: Ciara O'Sullivan/THS/NTG at NTGeMAG
> >From: Christine Connors/THS/NTG
> >Date: 04/16/2007 10:01AM
> >cc: Alan Evans/THS/NTG at NTGeMAG, Heinz Deiter/THS/NTG at NTGeMAG, John
> >Hester/THS/NTG at NTGeMAG, Louise Elliott/THS/NTG at NTGeMAG, Nick
> >Tyllis/THS/NTG at NTGeMAG, russell.thompson at wynhealth.org.au, Stephen
> >Brady/THS/NTG at NTGeMAG, Stephen Foster/THS/NTG at NTGeMAG,
>wombat at octa4.net.au
> >Subject: Re: swapping to Metformin XR
> >
> >so what is other people's experience
> >will patients take the 4 tabs to make 2gm daily or do they prefer the
> >usual 1gm bd?
> >
> >Ciara: apart from the obvious issue of big tablets, is there any
>issues
> >taking metformin XR as 3gm single daily dose?
> >
> >
> >Dr. Christine Connors
> >Program Director PCD
> >NT Department of Health & Community Services
> >Phone: (08) 8922 8218
> >Fax: (08) 8922 7714
> >Mobile: 0401 116 121
> >email: christine.connors at nt.gov.au
> >
> >
> >
> >
> >
> >
> >
> > Ciara O'Sullivan/THS/NTG
> >
> >
> >Ciara O'Sullivan/THS/NTG
> >
> >14/04/2007 07:31 PM
> >To
> >
> >Alan Evans/THS/NTG at NTGeMAG, Stephen Foster/THS/NTG at NTGeMAG, John
> >Hester/THS/NTG at NTGeMAG, Louise Elliott/THS/NTG at NTGeMAG, Nick
> >Tyllis/THS/NTG at NTGeMAG, Heinz Deiter/THS/NTG at NTGeMAG,
> >russell.thompson at wynhealth.org.au
> >
> >cc
> >
> >Christine Connors/THS/NTG at NTGeMAG, wombat at octa4.net.au, Stephen
> >Brady/THS/NTG at NTGeMAG
> >
> >Subject
> >
> >Re: swapping to Metformin XR
> >
> >
> >
> >Hi team
> >
> >Metformin XR is now available in most remote clinics.
> >
> >I would like to emphasise that metformin XR and standard metformin 500
>mg
> >tablets are equivalent and when swapping from a usual treatment dose
>of
> >standard metformin of 1 g bd, you need to prescribe metformin XR 4
>tablets
> >daily. No down-titration is needed with subsequent up-titration.
> >
> >YES!!! The metformin XR tablets are pretty big and are actually the
>same
> >size (but bulkier) than metformin 1 g tablets. You need to show the
> >patients what they are getting as some patients are horrified and
>refuse
> >to swap.
> >
> >I think using metformin XR in usual treatment doses of 2 g per day is
>
>very
> >useful for patients on few other tablets. However use of metformin XR
> >poses some real problems for us as clinicians; on the one hand we want
>to
> >provide convenient once daily medications (improves compliance) but on
>
>the
> >other hand, prescribing 4 whoppers in addition to a handful of other
> >morning medications is very off putting for many patients (reduces
> >compliance).
> >
> >This is the doctors' s dilemma. However, the solution is not to
>prescribe
> >half the previous standard dose of meformin (ie swapping from
>metfrormin
>1
> >g bd to metformin XR 1 g od) which potentially deprives the patient
>of
> >useful treatment, and this is what I am seeing on a lot of the scripts
>at
> >the moment!
> >
> >Cheers - CIara
>
>*********** END FORWARDED MESSAGE  ***********
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