Sinus cavities, the hollow spaces found in the face, are normally free of bacteria, but discomforts such as congestion can allow bacteria to invade and reproduce. The result is called a sinus infection or sinusitis. According to the University of Maryland Medical Center, a sinus infection is classified as chronic when it lasts 12 weeks or longer. Physicians sometimes prescribe antibiotics to treat chronic sinusitis, but the Mayo Clinic suggests these infections are usually caused by something other than bacteria.
Amoxicillin
The Mayo Clinic points out that various brands of amoxicillin are prescribed to treat a sinus infection. Doctors often prescribe this drug for 10 to 14 days or longer, despite symptoms improving. It is important to finish the full prescription to prevent the development of antibiotic-resistant bacteria. Individuals with allergies to penicillin drugs should not take amoxicillin because of similarities between the two drugs.
Trimethoprim-Sulfamethoxazole
Trimethoprim-sulfamethoxazole is a combination antibiotic prescribed to treat sinus infections. The University of Maryland Medical Center points out that like amoxicillin, this combination drug is considered a broad-spectrum antibiotic, which means that it can kill a variety of strains of bacteria. Drugs.com points out that drugs of this type are given to treat long-lasting infections or more severe bacterial infections.
Doxycycline
American Family Physician indicates that nearly all cases of bacterial sinusitis treated with antibiotics resolve. While amoxicillin is the first-line therapy, doxycycline is an alternative when the infection does not respond to other drugs or is severe. Patients should use antibiotics only for moderate symptoms that do not improve after 10 days or that get worse after five to seven days.
Other Antibiotics
The University of Maryland Medical Center explains that when standard broad-spectrum antibiotics do not resolve a sinus infection within 21 to 28 days, doctors may prescribe another drug. Some choices include clarithromycin, azithromycin or levofloxacin. These drugs are often aggressive and begin with a larger dose on the first day of the prescription and continue with a steady dose for seven to 10 days or longer.
