Danilon is apparently more effective, dunno about the sugar content but unless you're giving lots I doubt it will heat him up or exacerbate eg laminitis.
You could also try Devils claw if it's a lameness issue.
If you're looking for herbal alternatives then there are the devils claw, and cat claw remedies though not sure how 'proven' they are at actually managing pain??????
Unless you are competing under rules why not use the real thing. It does exactly what it says on the tin and has kept millions of horses comfortable for a very long time.
One of my friends at the yard swears by Nobute for her mare. Shes been on it a few month and she thinks it works better than bute. Not sure abiout the sugar content of it though
How about Boswellia Seratta, you can buy it as this or a Pegasus suppliment called Nature Bute. It is also available for humans and is supposed to be very effective.
Do you have a willow tree? horses like to eat the leaves and bark as it is a natural aspirin to them or you can get white willow bark and make 'tea' with it, once it is fused in the water drain the bark out and pour the liquid on some chaff. Devils claw is very good also plus the Boswelia (sp).