I think the intended use for Dioralyte is for diarrhoea sufferers, but it’s good for any general re-hydration use, such as caused by the diuretic effects of Diamox.
Re-hydration is not limited to Dioralyte. Any soluble tablet or powder with the required vitamins, minerals and electrolytes are good. For my last trip out, I bought some generic fizzy tablets from Snow and Rock, which actually went some way to masking the taste of my chlorinated water.
This, plus Imodium should save you should you eat something dodgy on the trail.
Afterthoughts:
This stuff is pretty rank. I only used one sachet and stuck with my Zero tablets after that. I’d probably still take some in my first aid kit, but otherwise don’t bother. (Blackcurrant flavour my arse …)