Abstract: 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. 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.

Plain-language summary: 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. 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.