Is It Safe To Take Onecan For Nail Infection While Breastfeeding?

I am advised to take onecan 150 mg 1 tab per week for 3 months to treat a nail infection (nail is bit swollen and turned brown in shape with whitish powder like skin under the toenail) on my toe. It has been there since last 3 years....I am 30 years old and am breastfeeding my child who is one year old...