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Medicating Lyme Disease Before It Starts and After It Ends
Can antibiotics prevent the development of Lyme disease after a tick bite? Can they be used to treat some of its controversial late sequelae? New findings say "yes" to the first question and "no" to the second.
In the first study, 482 people (age, 12 or older) in areas endemic for Lyme who were bitten by ticks were randomized to receive a single 200-mg dose of doxycycline or placebo (after confirmation that the ticks were species capable of transmitting Lyme). Erythema migrans developed in 1 doxycycline recipient and 8 placebo recipients -- a significant difference. No patients in either group experienced other clinical manifestations of Lyme or asymptomatic seroconversion. Only bites from partially engorged nymphal ticks resulted in Lyme. Side effects, primarily gastrointestinal, occurred in 30 percent of doxycycline recipients.
In the second study, antibiotics were found to be ineffective in patients with confirmed histories of Lyme and symptoms (e.g., arthralgia, fatigue, memory loss) that had persisted for a mean of 4.7 years. Patients (78 seropositive for Lyme, 51 seronegative) were randomized to receive either placebo or 30 days of intravenous ceftriaxone followed by 60 days of oral doxycycline. None had spinal fluid cultures or PCR assays positive for Lyme spirochetes. The study was stopped when no significant improvement in intensity of symptoms or in quality of life was evident in the antibiotic groups at 30, 90, or 180 days after enrollment.
Comment: These results add important data to the Lyme disease literature but are unlikely to resolve controversial questions. Antibiotic prophylaxis after tick bites does reduce overall risk for infection, but it is certain to perform far worse in ordinary practice, where ticks rarely are submitted for analysis. An editorialist suggests that prophylaxis be reserved for high-risk bites that occur in high-risk areas. As for the persistent asthenia ascribed to chronic Lyme, advocates of lifelong antibiotics for afflicted persons are unlikely to be swayed by good scientific evidence arguing against it.
— A Zuger
Published in Journal Watch General Medicine July 6, 2001
Citation(s):
Nadelman RB et al. Prophylaxis with single dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N Engl J Med 2001 Jul 12 345 79-84.
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- Medline abstract (Free)
Klempner MS et al. Two controlled trials of antibiotic treatment in patients with persistent symptoms and a history of Lyme disease. N Engl J Med 2001 Jul 12 345 85-92.
- Original article (Subscription may be required)
- Medline abstract (Free)
Shapiro ED. Doxycycline for tick bites -- Not for everyone. N Engl J Med 2001 Jul 12 345 133-134.