SATURDAY, Dec. 20, 2003 (HealthDayNews) -- When most people get a prescription filled for antibiotics, the last thing they're thinking about is how the medicine will get to where it's supposed to work.
All they're thinking about is relief.
But the way an antibiotic is delivered is important, because it can affect both the strength of the medicine as well as the risk of side effects.
If your infection is on or near the surface of the skin, your doctor will often prescribe a topical antibiotic, which means you apply it directly to the infection. Conjunctivitis and vaginal yeast infections are typical of such problems.
But most infections reside inside the body. So they require so-called systemic antibiotics, which -- like pills or intravenous medicines -- are taken internally and travel through the body to the infection site.
"There have been topical antibiotics for a long time, but they have a limited number of uses," says Dr. David Calfee, an epidemiologist at Mount Sinai Medical Center in New York City. "The majority of infections require systemic antibiotics."
Still, topical antibiotics can be quite valuable, Calfee adds.
"Topical antibiotics have the advantage of delivering high concentrations of medicine to a specific site," he says, while systemic antibiotics have to be weaker to reduce the risk of side effects to the whole body.
Another plus to topicals, says Calfee: Because they are targeted against specific ailments, their use is less likely to lead to antibiotic abuse or resistance.
Tuberculosis, gonorrhea, malaria and childhood ear infections are just some of the health problems that have become increasingly resistant to the antibiotics created to treat them. That's because bacteria and other infection-causing germs are resilient and can develop ways to survive drugs meant to destroy or weaken them, according to the U.S. Food and Drug Administration.
Calfee says "topicals may reduce antibiotic resistance" because many commonly used systemic antibiotics are designed to fight a number of bacteria. And they're often prescribed without knowing exactly which germ is causing the infection.
"They're used for superficial infections of the skin and ailments like conjunctivitis and vaginal yeast infections," Calfee says. "You have to be very comfortable that the infection is very superficial."
But doctors are finding new ways to deliver topical antibiotics to more-difficult-to-reach areas of the body.
For instance, some physicians are using topically delivered antibiotics in the deep nasal cavity for the treatment of severe sinusitis, an inflammation of the sinuses, says Dr. Winston Vaughan, director of Stanford University's Sinus Center.
In this method, a patient uses a machine called a nebulizer to deliver an aerosolized version of medications -- including antibiotics -- by breathing through the nose to target the lining of the sinuses. The treatment takes about 20 minutes and is done two or three times daily for three weeks, he says.
"Its use is very limited: for people who have failed with oral or intravenous antibiotics," Vaughan says. But, he adds, this system of delivery allows the drugs to get directly to the infection site.
Vaughan, who has published research on medications used with the delivery system, says the technique has offered relief to some long-term sinusitis sufferers who failed to find relief from oral or intravenous antibiotics.
Dr. Christopher Shaari, an otolaryngologist at Hackensack University Medical Center in New Jersey, has also had success with this topical delivery of antibiotics to treat severe sinusitis.
"I reserve this for those with chronic sinusitis who have not responded to oral antibiotics," says Shaari, who has no connection with the manufacturer.
"This delivery has fewer systemic side effects and will not worsen underlying illnesses, like inflammatory bowel disease," he adds. "Also, you can administer a stronger dosage, and it's relatively easy to do. There are no catheters or other IV [intravenous] apparatus."
Still, Shaari says, this is an exceptional use of topical medicines.
"This is a unique mechanism for treating the mucosal cavity," he says, "but only when you've exhausted the oral treatments."
Topical antibiotics aren't for everyone or every ailment. But the next time you're battling a bug, ask your doctor if they might be an option for you.
More information
Visit the U.S. Food and Drug Administration for information about how best to take your medicines. The National Institutes of Health has an interesting booklet on how drugs are developed.
