My 8 yr old takes loratadine syrup everyday for allergies, but her sinuses are very congested, is it ok to give her children's mucinex (guaifenesin) with it?

Yes it is ok: Yes it may be ok to give musinex along with loratadine.

Nasal congestion: You can but a better treatment is a saline nasal spray that should help with the congestion.

Ok but: It is ok to give Mucinex (guaifenesin) but unless it's Mucinex (guaifenesin) d it would not do anything to decongest your child's "sinuses". Consult your doctor for a rx nasal spray or allergist to find out what your child may be allergic to.

Yes: you can give them together. Loratadine though doesn't help congestion, it helps control sneezing, runny nose and nasal itching, Mucinex would loosen the mucus secretions, also saline nasal washes can help some, if no improvement , better see her doctor for assessment, wish you both wellness