Enhanced analgesic activity by cyclodextrins - a systematic review and meta-analysis.

INTRODUCTION: Analgesics can be ineffective in treating some types of pain, hence, improved drug delivery systems could optimize their efficacy. AREA COVERED: The authors conducted a systematic review to evaluate the analgesic activity of compounds complexed in cyclodextrins, analyzing whether these complexes improved analgesic efficacy. The search terms 'analgesics', 'cyclodextrins' and 'drug effects' were used to retrieve articles in SCOPUS, PUBMED and EMBASE. A total of 22 papers were identified. In the clinical studies, there was greater efficacy in the complexed drug when compared with control groups, with differences ranging from 25 to 83%. Through a meta-analysis, the preclinical studies showed that the complexed drug had a significantly (p < 0.01) greater effect than the non-complexed drug. EXPERT OPINION: The use of cyclodextrins can improve the efficacy of analgesic compounds, and they are an important tool in the search for greater analgesic effect. They may also be a way to reduce the therapeutic doses, and hence increasing the potential of the drug.