Can i nurse while taking azithromycin for a sinus infection?

Check with pediatric: You should check with a pediatrician, or your doctor for this. Some medications can be secreted in breast milk and thus effect the baby.

Yes: Zithromax is an antibiotic we can give to infants aged 3 months or older. Have not heard of any significant reason to stop breastfeeding just because mom is taking Azithromycin (zithromax)... Which means any changes seen in the baby are probably a coincidence and not caused by the small amounts of antibiotic in the breast milk.