It is my kind advice for you that you should make appointment with a lady doctor as early as possible. Ask the doctor the above question. you will get the right answer.
When breastfeeding a mother should not take any drugs at all without consulting with her doctor first. All drugs can get into the milk supply and therefore get to the baby. If you need something to help with your medical problem dont take Imodium unless you stop breastfeeding or your doctor says it is alright to take it.
Immodium is considered to usually be safe during breastfeeding. It uses loperamide. However, Kaopectate, which uses kaolin-pectin, is considered more safe. Check with your doctor for the final word.
I'm breastfeeding my daughter and I haven't taken anything short of prenatal vitmains because I don't trust anything and I'm not sure if its safe or not. So to be safe rather than sorry I've made the concious decision not to take anything.