X-Message-Number: 26680
Date: Sat, 23 Jul 2005 08:46:32 -0400
From: Thomas Donaldson <>
Subject: re: D Skrecky's Msg 26669

For Doug Skrecky:

The trouble with phenformin is that it had toxic effects on humans when
they tried it for their diabetes.

However there is an experiment going on right now (and which may have
actually concluded by now) with a related antidiabetic drug,
metformin. A lifespan test funded by the LIFE EXTENSION FOUNDATION
is now going on with metformin. Its importance comes from the fact
that it may work in humans too, because metformin doesn't have the
same toxic effects as phenformin.

I discuss metformin briefly in the latest version of the GUIDE TO
ANTIAGING DRUGS, in Appendix 2: DRUGS WAITING  IN THE WINGS. When I
get full references on the result of this lifespan experiment I will
put together one more chapter on it (or add it to Chapter 11).

Among other points these experiments tell us that even rats and
mice aren't always close enough to us that results with them 
translate over with no problems. And looking at toxicity of a drug
in humans takes far less time than testing its lifespan effect
in humans!

I don't know if buformin has ever been used in humans. Diphenylhydantoin
is an alternative name for what is popularly called dilantin, and
does increase lifespan in tests on rats (Chapter 11 of the GUIDE,
again).

               Best wishes and long long life to all,

                      Thomas Donaldson

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