Are antibiotics effective for the treatment of Lyme disease affecting the nervous system?
In humans, a bacterium called Borrelia burgdorferi causes Lyme disease. People become infected when bitten by ticks carrying the bacterium. The person may experience symptoms in the joints, skin, muscles, and nervous system (peripheral nerves (nerves outside the brain and spinal cord), the brain, and the spinal cord). Without antibiotic treatment, neurological Lyme disease either may resolve or cause long-term problems. Neurological Lyme disease differs between Europe and the United States, probably because of differences in B. burgdorferi. Limited information exists about which antibiotics are better for the treatment of neurological Lyme disease.
We found seven trials studying antibiotic treatments for neurological Lyme disease. All but one trial compared different antibiotics. The other trial compared the treatment effects of oral amoxicillin to placebo following initial ceftriaxone treatment. The trials included 450 Europeans. The antibiotics tested were penicillin G, doxycycline, ceftriaxone, and cefotaxime. One of the trials involved children only, while the others included mostly adults. We only selected studies in which treatment allocation was determined by chance (randomly), as such studies provide the best information for comparing the effects of different treatments. Most studies were not blinded (meaning that those taking part and the study staff knew the treatment being given). We could not find any studies of antibiotic treatments for neurological Lyme disease from the United States. No studies assessed the effects of delaying the start of treatment.
Key results and quality of the evidence
The seven studies were too different for their results to be combined, so we analyzed them individually.
None of the studies provided clear evidence that one antibiotic was better than another. One study failed to find evidence that a second and longer treatment with an oral antibiotic (amoxicillin) offered any extra benefit following initial intravenous treatment with ceftriaxone. As none of the other studies used a dummy treatment (placebo), the extra benefit offered by antibiotic treatment over recovery that occurs naturally is unknown. In general, the treatment was tolerated well, although the quality of adverse event reporting in most studies appeared to be low.
The results indicate that treatment with any of the four antibiotics produced similarly good outcomes for treatment of neurological Lyme disease in Europe. A second treatment with amoxicillin does not appear to provide added benefit to ceftriaxone. We found no trials of antibiotics for treatment of neurological Lyme disease in the United States.
The evidence is current to October 2016.
There is mostly low- to very low-quality clinical evidence from a limited number of mostly small, heterogeneous trials with diverse outcome measures, comparing the relative efficacy of central nervous system-penetrant antibiotics for the treatment of LNB. The few existing randomized studies have limited power and lack consistent and well-defined entry criteria and efficacy endpoints. It is not possible to draw firm conclusions on the relative efficacy of accepted antibiotic drug regimens for the treatment of LNB. The majority of people are reported to have good outcomes, and symptoms resolve by 12 months regardless of the antibiotic used. A minority of participants did not improve sufficiently, and some were retreated. These randomized studies provide some evidence that doxycycline, penicillin G, ceftriaxone, and cefotaxime are efficacious in the treatment of European LNB. No evidence of additional efficacy was observed when, in one study, an initial antibiotic treatment with intravenous ceftriaxone was followed by additional longer treatment with oral amoxicillin. There is a lack of evidence identified through our high-quality search strategy on the efficacy of antibiotics for treatment of LNB in the United States.
Various central nervous system-penetrant antibiotics are bactericidal in vitro and in vivo against the causative agent of Lyme neuroborreliosis (LNB), Borrelia burgdorferi. These antibiotics are routinely used clinically to treat LNB, but their relative efficacy is not clear.
To assess the effects of antibiotics for the treatment of LNB.
On 25 October 2016 we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase. We searched clinical trial registers on 26 October 2016. We reviewed the bibliographies of the randomized trials identified and contacted the authors and known experts in the field to identify additional published or unpublished data. There were no language restrictions when searching for studies.
Randomized clinical trials of antibiotic treatment of LNB in adults and children that compared any antibiotic treatment, including combinations of treatments, versus any other treatment, placebo, or no treatment. We excluded studies of entities considered as post-Lyme syndrome.
We used standard methodological procedures expected by Cochrane.
We identified seven randomized studies involving 450 European participants with LNB for inclusion in this systematic review. We found no trials conducted in the United States. Marked heterogeneity among these studies prevented meta-analysis. None of the studies included a placebo control on the initial antibiotic treatment, and only one was blinded. None were delayed-start studies. All were active comparator studies, and most were not adequately powered for non-inferiority comparison. The trials investigated four antibiotics: penicillin G and ceftriaxone in four studies, doxycycline in three studies, and cefotaxime in two studies. One study tested a three-month course of oral amoxicillin versus placebo following initial treatment with intravenous ceftriaxone. One study was limited to children. The trials measured efficacy using heterogeneous physician- or patient-reported outcomes, or both. In some cases cerebrospinal fluid analysis was included as an indirect biomarker of disease and outcome. None of the studies reported on our proposed primary outcome, 'Improvement in a measure of overall disability in the long term (three or more months).' None of the trials revealed any between-group differences in symptom resolution in response to active treatment. In general, treatment was tolerated well. The quality of adverse event reporting, however, was low.