Most runny noses are caused by allergies or by viruses. While Z Pak (oral azithromycin) is indeed an antibiotic used in the treatment of bacterial sinusitis - usually differentiated fro the above causes by the presence of high fever, severe pain behind the eyes, and thick greenish mucus - it would usually work. If it did not work for you, it is most likely that your symptoms were not caused by a bacteria. If you still have any of the signs of bacterial sinusitis (described above) you should see your doctor. If not, I would usually tell my patients to try over-the-counter cold and flu medication or an antihistamine. You could use some Vaseline on the skin around you nose to better protect the skin.