Background: Many studies have reported the effect of metronidazole on reducing blood lipids in different ways, but there is no comprehensive estimation about its effect. Therefore, this study aimed to determine the effect of metronidazole on reducing blood lipid by meta-analysis method.

Methods: This is a systematic review based on the reliable local and international websites including SID, Magiran, Iranmedex, ISI, Pubmed and Scopus. The keywords used for searching were metronidazole, blood lipid, cholesterol, triglyceride, low density lipoprotein (LDL) and height density lipoprotein (HDL). All articles published until the end of March, 2015, about the effect of metronidazole on blood lipids reduction which met the inclusion criteria were reviewed. Three independent reviewers checked studies for quality and eligibility and finally extracted the data. The collected data were analyzed by meta-analysis method (random effects model) and by means of Stata, ver. 11.1 (College Station, TX, USA) with a significance level of less than 5%.

Results: In 10 researches, 292 people had been studied and after taking metronidazole, the calculated amount of reduction in blood lipids was 11% (95% CI: 6%-16%) for cholesterol, 14% (95% CI: 4%-24%) for triglyceride and 8% (95% CI: 1%-15%) for low density lipoprotein (LDL) which was statistically significant (P= 0.001). The amount of increase in high density lipoprotein (HDL) was also calculated to be 1% (95% CI: 1%-2%) which was not statistically significant (P= 0.08).

Conclusion: The results of this study showed that, using metronidazole leads to decrease in the amount of cholesterol, triglyceride and low density lipoprotein (LDL) but it seems that it has not any effect on the increase in high density lipoprotein (HDL).