Allopurinol and Colchicine are both for treating gout, what are the ingredients and effects of them?

I heard that colchicine is for treating acute gout, and you should stop taking if you have no pain, and should chage to taking Allopurinol to control the disease, is this true? And What are the side effects for the two drugs? Can the two drugs be taken at the same time?

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