There is very little literature available re the use of colchicine and safety in breastfeeding. I would suggest to discuss with your specialist re an alternative drug if you are keen to continue breastfeeding. I am unable to comment re safety of pump and dump as it would depend on the exact pharmacokinetics of the drug ( how it is metabolised in the body, your body weight, peripheral binding, half life, what dosage you are on etc).
Sorry, not a terribly useful answer, but colchicine is not one of the those very common drugs breastfeeding mothers take!
