Antibiotics May Prevent Lyme Disease
June 12, 2001 -- New findings released Tuesday show that an antibiotic taken within 72 hours of being bitten by a deer tick carrying Lyme disease can prevent people from developing the illness.
Only about 3% of people who are bitten by ticks will develop Lyme disease, which is characterized by persistent fatigue and pain. But the new study confirms that the risk is highest for people bitten by ticks that haven't yet reached the adult stage and are at least partially engorged with blood. Although the study will not be published until next month, The New England Journal of Medicine released it early because of the treatment potential.
"The important thing I think is that Lyme disease can be prevented," says the study's author Robert B. Nadelman, MD, of New York Medical College and the Lyme Disease Diagnostic Center at Westchester Medical Center in Valhalla, N.Y.
He tells WebMD that although antibiotics won't be recommended for everyone with tick bites this summer, knowing they work gives doctors and patients a much-needed addition to their prevention methods.
The best-known ways to prevent Lyme disease are avoiding areas known to be infested with deer ticks; wearing clothing that covers your skin when you are potentially going to be exposed to ticks; and checking your body, hair, and clothes carefully for any signs of a tick after being in the woods or other areas where ticks are prevalent.
In Nadelman's study of nearly 500 adults, a single dose -- two pills -- of the antibiotic doxycycline taken within 72 hours of being bitten was 87% effective in preventing Lyme disease.
But because the antibiotic treatment causes side effects like nausea and vomiting in about 30% of people, experts say doctors shouldn't give it unless the person is fairly certain the tick that bit them was fat -- as opposed to flat, meaning it was somewhat engorged -- and that it was indeed a tick.
"Many persons living in areas where there is a lot of Lyme disease are experts at identifying ticks," says Nadelman. "But on the other hand there are many people ... bringing in what they think are ticks but which many times are debris, dirt, spider mites, or perhaps other kinds of ticks that are not deer ticks."
If you've been infected with Lyme disease without realizing it, a characteristic 'bulls-eye' rash will develop at the site of the bite within days to weeks. At that point, a 10- to 21-day course of antibiotics will be started and the success rate of treatment is about 95% or better, according to Eugene D. Shapiro, MD, of Yale University School of Medicine in New Haven, Conn.
"There's a myth that Lyme disease produces these horrible, intractable symptoms," he says. "But the therapy is extremely effective."