AimThe aim of this systematic review was to assess the quality and outcomes of clinical trials investigating the effect of St John's wort extracts on the metabolism of drugs by CYP3A.
MethodsProspective clinical trials assessing the effect of St John's wor t (SJW) extracts on metabolism by CYP3A were identified through computer-based searches (from their inception to May 2005) of Medline, Cinahl, PsycINFO, AMED, Current Contents and Embase, hand-searches of bibliographies of relevant papers and consultation with manufacturers and researchers in the field. Two reviewers selected trials for inclusion, independently extracted data and recorded details on study design.
ResultsThirty-one studies met the eligibility criteria. More than two-thirds of the studies employed a before-and-after design, less than one-third of the studies used a crossover design, and only three studies were double-blind and placebo controlled. In 12 studies the SJW extract had been assayed, and 14 studies stated the specific SJW extract used. Results from 26 studies, including all of the 19 studies that used high-dose hyperforin extracts ( > 10 mg day − 1 ), had outcomes consistent with CYP3A induction. The three studies using low-dose hyperforin extracts ( < 4 mg day − 1 ) demonstrated no significant effect on CYP3A.
ConclusionThere is reasonable evidence to suggest that high-dose hyper forin SJW extracts induce CYP3A. More studies are required to determine whether decreased CYP3A induction occurs after low-dose hyperforin extracts. Future studies should adopt study designs with a control phase or control group, identify the specific SJW extract employed and provide quantitative analyses of key constituents.
Objective: To evaluate the efficacy of Lactobacillus rhamnosus GG in the prevention of antibiotic-associated diarrhoea. Data Sources: A computer-based search of MEDLINE, CINAHL, AMED, the Cochrane Controlled Trials Register and the Cochrane Database of Systematic Reviews was conducted. A hand-search of the bibliographies of relevant papers and previous meta-analyses was undertaken. Review Methods: Trials were included in the review if they compared the effects of L. rhamnosus GG and placebo and listed diarrhoea as a primary end-point. Studies were excluded if they were not placebo-controlled or utilised other probiotic strains. Results: Six trials were found that met all eligibility requirements. Significant statistical heterogeneity of the trials precluded meta-analysis. Four of the six trials found a significant reduction in the risk of antibiotic-associated diarrhoea with co-administration of Lactobacillus GG. One of the trials found a reduced number of days with antibiotic-induced diarrhoea with Lactobacillus GG administration, whilst the final trial found no benefit of Lactobacillus GG supplementation. Conclusion: Additional research is needed to further clarify the effectiveness of Lactobacillus GG in the prevention of antibiotic-associated diarrhoea.
Herbal products are popular among women during the perinatal period. St John's wort (SJW), Hypericum perforatum, is a common remedy for mild depression, a problem prevalent in this population. Although the safety of herbal products must be investigated, ethical issues constrain intervention studies in humans. Hence, animal studies often inform clinical decisions. The objective of this study is to systematically review rodent studies assessing the safety of SJW during the perinatal period. A literature search to November 10, 2017, identified 10 rodent studies that met a priori inclusion criteria. Study quality was evaluated according to both the Systematic Review Centre for Laboratory animal Experimentation tool for assessing bias and recommendations for appropriate reporting of herbal medicine research. Significant methodological limitations were found in each of the studies reviewed. These limitations include the lack of botanical verification and omission of extract characterization, inadequate explanation of dosage rationale, and absence of bias limiting protocols. Critical appraisal with contemporary tools indicates that each of the reviewed studies lacks appropriate rigour, rendering the results unreliable. Despite this, these papers are used in the rationale for recommending or contraindicating SJW during pregnancy and lactation.
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