Physicians prescribe hundreds of millions of dollars worth of antibiotics each year for people with sinusitis. These bacteriaslaying medications generally are effective.

In most cases, antibiotics eliminate the infection-causing bacteria, allowing inflamed nasal mucous membranes to shrink and your sinuses to drain. Unfortunately, it’s not always so straightforward.

Antibiotics sometimes fail to do away with the offending bacteria or provide only temporary improvement, with a return of symptoms as soon as you stop taking the medication.

Also, antibiotics can be expensive and they have side effects. So let’s take a look at the world of antibiotics for sinusitis: how they work, the different types that are available, and their benefits and drawbacks.

Symptom Relief

Taken in pill form, antibiotics are absorbed in the stomach and distributed through the body via the bloodstream. As a result, they are effective in areas of the body that have a good blood supply.

The well-vascularized mucous membranes inside your sinuses can deliver an adequate dose of antibiotic to rapidly kill bacteria for most sinus infections. You typically notice an improvement in symptoms within forty-eight hours.

Pain subsides, swelling goes down, and thick mucus becomes thinner. You may note a temporary increase in postnasal drip a sign the antibiotic is working. However, with a severe infection that fills a sinus cavity with mucus or pus, there may not be an adequate blood supply in the center of the sinus to deliver the antibiotic.

Bacteria living in the fluid may continue to multiply, so it takes weeks, instead of days, to kill enough bacteria to allow the sinuses to fully open and drain the offending microorganisms. Also, antibiotics sometimes fail because bacteria are resistant to them.

If an infection fails to show signs of improvement after ten days or if an infection goes away but comes back within a few weeks, your doctor has two options: having you take the first antibiotic again for a longer period of time or trying a different antibiotic that kills a larger variety of bacteria (what’s known as a broad-spectrum antibiotic).

For chronic sinus infections, it’s not unusual for an antibiotic to be prescribed for three or more weeks. To improve the likelihood of success, it’s important to complete the full course.

Choosing an Antibiotic

From a physician’s perspective, selecting the “best” antibiotic for a given case of sinusitis can be a guessing game. Why is this so? First, there’s an appalling lack of information on the effectiveness of different antibiotics for the treatment of chronic sinusitis.

You may be surprised to learn that the U.S. Food and Drug Administration (FDA) has yet to approve even one antibiotic for the treatment of chronic sinusitis. Many antibiotics are approved to treat acute sinusitis, and doctors simply prescribe these same antibiotics for chronic sinusitis.

As a result, there’s little economic incentive for drug manufacturers to seek government approval a difficult and expensive proposition, because chronic sinusitis is not one disease but a spectrum of many diseases.

Therefore, we don’t have scientific data demonstrating one antibiotic’s superiority over another for chronic sinusitis, nor do we know the optimal dose or dose duration.

A second treatment dilemma relates to the offending bacteria. Recall from previus article that one of three bacteria causes most cases of acute sinusitis: Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.

Chronic sinusitis is more complicated. There are more potential culprits, and infections are often polymicrobial, meaning two or more bacteria contribute to the infection.

We know that Staphylococcus aureus (also referred to as Staph aureus, or simply as staph) is the critter found most often when cultures of chronic sinus infections are taken, arising in about half of all cases.

A host of other bacteria with strange-sounding names may also be present, including Pseudomonas, Klebsiella, Peptostreptococcus, Fusobacterium, and Bacteroides. It’s not even that uncommon to find Escherichia coli (E. coli) growing in chronically infected sinuses.

You may remember that bacterium from 1993, when hamburger meat contaminated with E. coli caused several fatalities at fast-food restaurants.

Fortunately, it’s not the same strain of E. coli that causes sinus infections, which is relatively easy to treat with proper antibiotics. Because of the large variety of bacteria that can cause a chronic infection, culture-directed therapy is the most accurate way to select the proper antibiotic.

In cases where the ENT doctor sees pus flowing from a sinus during an endoscopic examination, a sample can be taken with a small Q-tip. This sample is immediately placed on a culture plate and incubated.

Five to seven days later, a lab technician identifies the bacteria that have grown and runs tests to see which antibiotics are effective against them. Armed with this information, the ENT doctor can prescribe an antibiotic that has a high likelihood of working.

Classes of Antibiotics

There are four major classes of antibiotics used to treat chronic sinusitis penicillins, cephalosporins, macrolides, and quinolones as well as a few other minor categories. Table below shows you the generic and brand names of many of these antibiotics.

Antibiotics Used to Treat Sinusitis

Class	Examples	Brand Name	Cost*
Penicillins	Amoxicillin	(Generic)	$
	Amoxicillin clavulanate	Augmentin	$$
Cephalosporins	Cephalexin	Keflex	$
	Cefdinir	Omnicef	$$
	Cefixime	Suprax	$$
	Cefpodoxime	Vantin	$$
	Cefuroxime	Ceftin	$$
Macrolides	Erythromycin	(Generic)	$
	Azithromycin	Zithromax	$$
	Clarithromycin	Biaxin	$$
	Telithromycin	Ketek	$$
Quinolones	Ciprofloxacin	Cipro	$$$
	Gatifloxacin	Tequin	$$$
	Levofloxacin	Levaquin	$$$
	Moxifloxacin	Avelox	$$$

*Cost: $ low cost; $$ moderate cost; $$$ expensive.

• Penicillins - Old-fashioned penicillin is no longer used for sinusitis, because it has lost its effectiveness against numerous bacteria. Instead, we now use amoxicillin, a variant of penicillin.

Amoxicillin is usually effective, but about one-third of patients will have resistant bacteria. Even so, because of its low cost and minimal side effects, amoxicillin is often the first antibiotic prescribed when someone is diagnosed with chronic sinusitis.

If amoxicillin fails or if a physician believes it might a common alternative is Augmentin, which combines amoxicillin with clavulanate, a drug that inhibits an enzyme that would ordinarily render amoxicillin inactive.

A ten-to twenty-one-day course of Augmentin is effective treatment for most people with chronic sinusitis who develop an infection.

• Cephalosporins - Cephalosporins are a good alternative to penicillins for the treatment of sinusitis; they are commonly used for cases of chronic sinusitis that don’t respond to amoxicillin or Augmentin.

Cephalosporins are effective against Staph aureus about 90 percent of the time. Because staph is a common source of postoperative infection, a course of cephalosporin is commonly prescribed immediately following sinus surgery.

• Macrolides - Macrolides are a powerful class of antibiotics known for their high effectiveness in patients with sinusitis. They are useful for patients with an allergy to penicillin or amoxicillin.

Zithromax and Ketek (which actually belongs to a similar class of antibiotics called ketolides) are available in prepackaged five-day courses for acute flare-ups.

• Quinolones - Quinolones are another powerful class of broad-spectrum antibiotics.

They are particularly effective against what are known as gram-negative bacteria, such as Pseudomonas, which can be the cause of resistant sinus infections.

For this reason, they’re usually used as a last resort, when a sinus infection hasn’t responded to other classes of antibiotics.

• Others - A few other antibiotics are also used for sinusitis.

The combination of trimethoprim and sulfamethoxazole (Septra, Bactrim) is effective but contains sulfa, which is a common cause of allergic reactions, some of which can be serious.

Clindamycin (Cleocin) is particularly active against a robust type of bacteria known as anaerobes, which do not need oxygen to survive. With prolonged use, this antibiotic can cause a severe form of diarrhea.

Linezolid (Zyvox) is effective in treating sinusitis caused by a resistant form of staph (called methicillin-resistant Staph aureus, or MRSA) but is extremely expensive, so it’s reserved for the most difficult cases.

Minimizing Side Effects

All antibiotics put you at risk for side effects, with the broadspectrum antibiotics tending to have more severe side effects. Your doctor will likely discuss side effects for any antibiotic he or she prescribes. Rather than cover every side effect here, I’ll discuss the most common ones:

• Allergic reactions. True allergic reactions in which people’s immune systems are triggered into action when they take antibiotics are rare, accounting for only 5 to 10 percent of all side effects.

But these reactions can be severe. The most serious allergic reaction involves the onset of hives, swelling of the throat, and difficulty breathing shortly after taking the medication.

These symptoms, known as anaphylaxis, are similar to those that occur in people with severe allergies to peanuts or bee stings and require immediate treatment in an emergency room.

A more common but less serious allergic reaction from antibiotics is the development of a rash. Most rashes occur within a few days of starting the medication. If one occurs, stop taking the antibiotic immediately and inform your doctor.

• Stomach problems. Gastrointestinal disorders, including nausea and diarrhea, are the most common side effect of antibiotics. Such problems are more common with cephalosporins, macrolides, and quinolones than with penicillins.

Diarrhea can occur because in addition to killing the bacteria in your sinuses, antibiotics do away with bacteria in your bowel that help you digest food.

GI side effects tend to be worse on an empty stomach, so taking antibiotics with food can help you avoid or lessen these side effects. Eating a six-ounce cup of yogurt once or twice a day, which replenishes bacteria that aid in digestion, can also be helpful.

• Yeast infection in women. Antibiotics also may alter the balance of microorganisms that normally reside in the vagina. Antibiotics suppress bacteria that have an antifungal effect, resulting in an overgrowth of yeast.

Antifungal medications to treat such yeast infections are available over the counter in topical ointments and by prescription in pill form.

• Sensitivity to sunlight. While taking a quinolone antibiotic, your skin is unusually susceptible to sunlight.

If you’re exposed to the sun while taking Cipro or a similar antibiotic, you may suffer a particularly bad sunburn, so be sure to wear a hat and use sunscreen.

• Unpleasant taste. Some macrolides, such as Biaxin, can produce a metallic taste.

• Drug interactions. Antibiotics may interact with other drugs you’re taking, particularly blood pressure, bloodthinning, and seizure medications. Always inform your physician of any medications you take.

• Effects on pregnancy. All medications, including antibiotics, present a risk during pregnancy. Your obstetrician can advise you on which antibiotics are considered safest during pregnancy.

Short- and Long-Term Dosing Regimens

A typical course of antibiotics for sinusitis lasts from ten to fourteen days. For more severe infections, the course can be extended to three to six weeks. However, in some circumstances, patients may benefit from antibiotic regimens that are either shorter or longer than the typical course.

On the short end are the newer, powerful antibiotics such as Zithromax and Ketek that come in three- and five-day packages. Such short-dosing regimens are effective for people with acute sinusitis as well as those with chronic sinusitis who experience acute flare-ups.

However, they may be less effective for individuals with severe infections. At the other extreme is a low-dose, long-term strategy, which may be appropriate for patients who continue to develop sinus infections even after repeated courses of antibiotics for conventional durations.

Such regimens involve half the normal daily dosage and last for two to six months. In theory, keeping the bacteria count down for a long stretch allows time for inflamed mucous membranes to heal. The sinuses can then drain better, and the likelihood of future infections is reduced.

Physicians started using this tactic based on its success among children with persistent ear infections. The potential drawback is that bacteria may develop resistance to the antibiotic, so the risk of this side effect must be carefully weighed against the potential benefit.

Topical and Intravenous Antibiotics

Although antibiotics are usually prescribed in pill form, they don’t have to be. In special circumstances, they may be more effective when administered topically or intravenously.

Topical Antibiotics

In theory, topical application of antibiotics directly into the nasal and sinus cavities makes a lot of sense, because the medication is applied in a relatively high dose where it’s needed. Furthermore, side effects should be less than with oral antibiotics, because the medication does not pass through the stomach or bloodstream.

In years past, you could have your local drugstore prepare a nasal spray from a powdered antibiotic mixed with saline. Nowadays, such compounding is too time-consuming and not costeffective for most pharmacists. Instead, private companies offer this service.

With a doctor’s prescription, they create an antibiotic solution and ship it to you with a nebulizer, which delivers the medication in a suspension of tiny droplets inhaled through the nose. If you frequently use antibiotics, you may wish to ask your physician about this method.

Companies active in this area include SinusPharmacy (which markets a device under the name Sinu- NEB) and SinusDynamics (which calls its nebulizer SinusAero). Some antibiotics are available as ointments that can be applied inside the nose.

Intravenous Antibiotics

Intravenous (IV) administration of antibiotics is only considered for the most severe sinusitis cases. The two most common scenarios are:

• people who do not respond to oral antibiotic therapy but are not good candidates for surgery.
• people whose infection spreads from the sinuses to surrounding tissue in the skin, eyes, or brain.

IV administration increases the medication’s effectiveness, because the level of antibiotic in the blood is higher than it would be with oral administration.

Cases requiring IV administration may be handled by an infectious disease specialist in consultation with an ENT specialist. Although IV administration often starts in a hospital, where the patient can be monitored for the initial dose, it continues at home, where a visiting nurse can provide assistance.

Patients can usually resume most daily activities, taking breaks to administer the antibiotic two to four times a day. In some cases, the patient wears a pump that automatically administers the dosage throughout the day. Courses of therapy usually range from ten days to six weeks.

Next, we’ll consider how everyday issues, such as diet, smoking and drinking, and the work environment, can affect your sinuses.