Is It Safe To Take The Medicine For Microscopic Colitis During Breastfeeding?

I am a 32 year old, my weight is 125 and my height is 5 foot. I am very healthy but I have been suffering with a problem for a year now. I have just been diagnosed with microscopic colitis. I am breastfeeding my almost 6 month old baby. The pharmacist says that the medicine my doctor wants me to take is not recommended and for me to take it at my own risk. Should I quit breastfeeding or is it safe to take the medicine and breastfeed?