Antibiotics fight the bacteria that are causing the sinus infection. They are prescribed by your physician and are used for 10 to 14 days. It is very important to finish the antibiotics even if you are feeling better. Failure to do so may result in the return of sinusitis, and it may be harder to treat. If you do not get better after the first course of antibiotics, a second antibiotic will be tried, often for a longer period of time.
Decongestants help clear the infection by draining the infected sinsuses.
They are available without a prescription and are most effective within the first 3 to 5 days of treatment. Antihistamines are not helpful unless you have allergies. This is because they may make your secretions thicker and harder to drain. Symptoms which are getting much worse despite treatment.