The pharmacists and doctors on line can respond better, but Pseudoephedrine
(sudafed) is a decongestant, not an antihistamine.  Therefore I do not think
it has as much drying effects, altho when I take it I seem to experience a
mild diuretic effect.
In general, II think it is better for bf moms to take a single med remedy
(like this one) rather than a multi-symptom one when they can.  I also think
it makes sense to  look at the meds our babies/toddlers take (like
pseudoephedrine, chlorpheniramine, brompheniramine, diphenhydramine -
ingredients in many OTC kids meds for colds, etc) when deciding what would be
safe to take.  At least that is what I do.

Laurie Wheeler, rnc, mn, ibclc