Flagyl is metabolized thru the dehydrogenase pathways, like alcohol. When taken together there can be side effects like antabuse has with alcohol.

The only suggestion I have is to support the metabolic pathway with thiamine (as we do for alcohol).
300mg of thiamine a day in divided doses may help. Thiamine is Vitamin B1 and very benign with no side effects.
Benfotiamine is an improved longer acting type of thiamine which is better, and costs a little more.

You can find it online here...
http://www.iherb.com/Search.aspx?kw=Benfotiamine
I use the Doctor's Best form, and it works for me. Local stores do not carry this as a rule.
If you choose this, I'd start with 300mg a day for a month, and if you see improvement, you may reduce to 150mg a day.

I believe that people who react to Flagyl, have an inherent weakness in the metabolism of this drug (and hence may not be metabolizing alcohol well either). The buildup of the aldehydes is what may be doing the damage. So I would not use alcohol at all while you do this treatment. You may not be able EVER to handle alcohol.

Not everyone gets this effect. So something in YOU is different from the majority.
This article suggests that some people do not metabolize this drug in the liver properly and it accumulates to toxic levels:
http://www.theannals.com/cgi/content...act/34/11/1273

And this paper...reports a toxic event in the cerebellum (which controls movement)...causing ataxia:
http://www.ajnr.org/cgi/content/abstract/24/8/1615