What are antibiotics?

Antibiotics are medications derived from naturally occurring chemicals produced by bacteria and molds to inhibit the growth of competing microorganisms.  Penicillin was discovered in 1929 by Alexander Fleming and its popular derivative amoxicillin remains effective for 80% of acute bacterial sinus infections and 99% of strep throat infections.  Although 60% of episodes of acute bacterial sinusitis will resolve without treatment, antibiotics have been consistently demonstrated to shorten the course of illness and reduce the frequency of complications from sinusitis.

When should antibiotics be used?

Antibiotics are recommended for acute bacterial sinusitis lasting longer than 10 days, or getting worse after the first week.  The most common symptoms include facial pain or pressure, nasal stuffiness or congestion, and thick, discolored nasal drainage.  Antibiotics are also commonly prescribed for chronic sinusitis, although many cases of chronic sinusitis are not caused by bacteria.

Why will my doctor not prescribe antibiotics over the phone?

Studies have shown that 80% of patients with acute sinusitis will improve in a week on antibiotics, while 73% of patients treated with placebo will improve.  Furthermore, antibiotics will do nothing to shorten the course of the common cold.  Overuse of antibiotics can breed resistant strains of bacteria and induce drug allergies in susceptible patients. Accordingly, we do not recommend antibiotics for sinus symptoms that appear to be improving spontaneously within the first 7-10 days. If you abuse antibiotics now, we may not have any options left when you really need them!

What is antibiotic resistance?

Bacterial antibiotic resistance is a significant problem in Richmond, Virginia, and throughout the United States. Many of the common bacteria that can cause sinusitis carry a gene for antibiotic resistance that can be turned on in the presence of antibiotics. After a few days of treatment, the gene becomes activated and can even travel between bacteria (in a capsule called a plasmid), creating resistance among a large population of bacteria. If you are not responding to a course of antibiotics within 4-7 days, you may have a resistant strain of bacteria. Consult your physician for an examination and possible culture or DNA analysis of your sinuses.  DNA analysis of sinus drainage allows us to identify the most dangerous resistant strains within 24 hours and to provide a complete analysis of all bacteria in your nose within 1 week.

Read more about DNA analysis of chronic ENT infections 

What are the most common antibiotics used for sinusitis?

Amoxicillin remains the drug of choice for acute, uncomplicated bacterial sinusitis.  Amoxicillin is most effective when given frequently enough to sustain adequate levels in the infected tissue.  While often prescribed twice daily, it is even more effective if taken in 3 or 4 divided doses.  Amoxicillin is typically prescribed for 7-10 days at a time.  While it is critical to finish the entire 10 day course of antibiotics when treating strep throat, there is evidence that shorter courses of treatment may be sufficient for most cases of sinusitis.  Amoxicillin is closely related to the parent compound penicillin and should not be prescribed in patients who are penicillin allergic.

Azithromycin is an alternative treatment for patients who are allergic to amoxicillin.  The principal advantage of the azithromycin is convenience — the recommended treatment for acute sinusitis is 500 mg once daily for only 3 days.  Unlike amoxicillin, the effectiveness of a azithromycin is enhanced by giving a large single dose rather than spreading the doses out.  For this reason, a course of azithromycin should be completed in 3 days or less for sinusitis (as in a Zithromax Tri-Pak), and should not be spread out over 5 days (as in a Zithromax Z-Pak).  Azithromycin induces antibiotic resistance to itself quickly if prescribed in doses that are too low to kill the bacteria.  This resistance lasts at least 3 months, so Zithromax should not be prescribed twice within 3 months . Alternatives related to azithromycin include clarithromycin (Biaxin), which is commonly taken twice daily for 10 days, and the older medications erythromycin and clindamycin which require 3-4 doses per day.

Cephalosporins and Augmentin (amoxicillin with clavulanic acid) are considered “broad-spectrum antibiotics”  because they have enhanced effectiveness against a wider range of bacteria, including those that are resistant to ordinary penicillin or amoxicillin.  If the patient does not improve within the first week on amoxicillin, a change to Augmentin or to a cephalosporin such as Ceftin, Cefzil, Omnicef, or Suprax is reasonable.  Although these drugs have a similar mechanism of action to penicillin, they generally can be taken in adequate doses once or twice daily.  These medications should be used with extreme caution in patients with a history of penicillin allergy, as cross-reaction may occur.

Cipro, Levaquin, and Avelox are generally considered third line antibiotics for uncomplicated sinusitis.  These medications still have a very low rate of resistance and are often our last resort before considering surgical intervention.  Allergic reactions are infrequent, but joint pain and tendon rupture have been described with patients taking these medications.  They also have increased complexity interacting with other medications.

Bactrim and tetracycline are older medications which do not routinely cover the broad-spectrum of bacteria that may grow in the sinuses.  However, they may have occasional use for patients with infections caused by known, resistant bacteria.  In particular, these medications are prescribed for staphylococcal infections that are resistant to cephalosporins and other penicillin derivatives.  This infection is known as methicillin-resistant staph aureus, or MRSA.

Topical antibiotics are a relatively new treatment option that has become popular for post surgical patients with chronic resistant bacteria.  A variety of antimicrobials including vancomycin and aminoglycosides that cannot be administered by mouth are available as a nasal spray or wash.  Recent studies have suggested that large volume nasal washes do a better job delivering antibiotics into the sinuses than nebulized sprays.  These antibiotics can be combined with potent antifungal medications and steroids, each of which will be selected by your physician based on culture results, and  custom mixed for you by a compounding pharmacist.  Bactroban nasal cream (mupirocin) can be applied inside the nostrils to reduce colonization with methicillin-resistant staph aureus (MRSA).

Additional resources:

Clinical practice guideline: adult sinusitis.   Rosenfeld RM, Andes D, Bhattacharyya N, Cheung D, Eisenberg S, Ganiats TG, Gelzer A, Hamilos D, Haydon RC 3rd, Hudgins PA, Jones S, Krouse HJ, Lee LH, Mahoney MC, Marple BF, Mitchell CJ, Nathan R, Shiffman RN, Smith TL, Witsell DL.  Otolaryngol Head Neck Surg. 2007 Sep;137(3 Suppl):S1-31.

Clinical practice guideline for the diagnosis and management of acute bacterial sinusitis in children aged 1 to 18 years.   Wald ER, Applegate KE, Bordley C, Darrow DH, Glode MP, Marcy SM, Nelson CE, Rosenfeld RM, Shaikh N, Smith MJ, Williams PV, Weinberg ST; American Academy of Pediatrics.  Pediatrics. 2013 Jul;132(1):e262-80.

Current concepts in topical therapy for chronic sinonasal disease.   Harvey RJ, Psaltis A, Schlosser RJ, Witterick IJ.  J Otolaryngol Head Neck Surg. 2010 Jun;39(3):217-31. Review.

Treatment options for chronic rhinosinusitis.   Suh JD, Kennedy DW.  Proc Am Thorac Soc. 2011 Mar;8(1):132-40. doi: 10.1513/pats.201003-028RN. Review.