December 1997
SAN FRANCISCO - A committee of the Infectious Diseases Society of America (IDSA) has developed practice guidelines for Lyme disease.
The committee, chaired by Benjamin Luft, MD, professor and chairman of the department of medicine, State University of New York (SUNY) at Stonybrook, divided its guidelines into several categories - tick bite prophylaxis, early Lyme disease, late Lyme disease and chronic Lyme disease.
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Treatment options for tick bite prophylaxis include:
The tick bite prophylaxis panel reviewed three studies that, when combined, included about 600 patients. Different regimens were used in each study, comparing penicillin or amoxicillin, or penicillin and tetracycline against placebo. The results showed that in the placebo group the risk of infection after a tick bite varied from 1% to 3%, with the overall chance of infection being 1.8%.
In two studies, there were no asymptomatic seroconversions. The committee recommended that there be no routine use of antimicrobial prophylaxis following tick bites. It further recommended that persons who develop rash, flu-like illness or signs or symptoms consistent with Lyme disease within a month after a tick bite seek prompt medical attention.
Lastly, the committee recommended that health care practitioners, particularly in endemic areas, become familiar with the clinical manifestations and recommended treatment for Lyme disease.
"There were two treatment options considered regarding early Lyme disease," Luft said. One was therapy with oral penicillin, tetracycline, amoxicillin, doxycycline, azithromycin (Zithromax, Pfizer) or clarithromycin (Biaxin, Abbott). The other was therapy with intravenous ceftriaxone (Rocephin, Roche).
Nadelman et al did a multicenter study comparing cefuroxime with doxycycline for the treatment of early Lyme disease. Both agents demonstrated about 90% efficacy. However, some patients later developed Lyme-related manifestations, so the overall efficacy was about 80%.
Another study compared 500 mg of azithromycin for seven days with 500 mg of amoxicillin for 20 days, and found that amoxicillin was more effective, with an overall efficacy of 88%. Amoxicillin was also more effective in preventing later manifestations of the disease.
A recent study in the New England Journal of Medicine comparing ceftriaxone given for 14 days with doxycycline given for 21 days. The study demonstrated that ceftriaxone and doxycycline were roughly equivalent in the treatment of early disseminated Lyme disease; with an 88% efficacy for doxycycline and an 85% efficacy for ceftriaxone.
The committee's recommendation for early Lyme disease was a 21-day course of doxycycline given at 100 mg twice daily, or amoxicillin given at 500 mg three times daily.
"Cefuroxime is a reasonable alternative, being as effective as doxycycline and amoxicillin, but it is more expensive," Luft said.
"To treat a patient with objective central nervous system infection, the recommendation is ceftriaxone for 14 to 28 days, although there are no good comparative North American trials on which to base this expert opinion," said Luft. "Macrolides are not recommended as first-line treatment for early Lyme disease, but they may be a useful alternative for patients who cannot tolerate b-lactams or tetracycline."
Most of the studies done on late Lyme disease have used ceftriaxone. A study by Detwhiler showed that seven patients responded well when treated with ceftriaxone. A subsequent study of 23 patients compared penicillin to ceftriaxone and found that ceftriaxone was 92% effective, while penicillin was 50% effective.
A multicenter, randomized study of 201 patients, sponsored by Hoffman LaRoche, compared two weeks of ceftriaxone to four weeks of ceftriaxone. The two-week regimen was found to have an efficacy of approximately 76%, while the four-week regimen was 70% effective.
The recommendation for late Lyme disease is ceftriaxone given at 2 g daily for 14 days. A 30-day course of doxycycline or amoxicillin may provide a cost-effective alternative, but further studies need to be performed, Luft said.
For patients with Lyme arthritis who continue to have joint swelling, a second course of oral therapy or ceftriaxone is recommended, along with nonsteroidal anti-inflammatory agents. If the persistent joint swelling is painful or limits function, arthroscopic synovectomy may reduce the period of joint swelling.
"There have been no treatment studies published on chronic Lyme disease," Luft said. "However, there are currently four randomized, controlled trials being conducted that will hopefully provide answers for how to manage patients with post-Lyme disease syndrome.
For more information:
- Luft B. Lyme disease. Presented at the Infectious Diseases Society of America 35th Annual Meeting. Sept. 13-16. San Francisco.
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