Why does amoxicillin after 5 days still not seem to be working for my child's sinus infection?

SINUSITIS: Amoxil (amoxicillin) rx for sinusitis should be given for 10 days. Consult your doctor.

Is it sinusitis?: Sinusitis is diagnosed in kids with cough & nasal discharge for >10 days OR fever (> 102.2) & thick nasal discharge > 3 days; Most get better within a week w/o treatment. Sinuses don't have a good blood supply so it can be difficult to treat, which is why antibiotics should be for 10-21 days. If this is a viral illness, antibiotics won't help. See your Dr. if not better in 2 days, sooner if worse