The effects of opium on the cardiovascular system: a review of side effects, uses, and potential mechanisms

Background In Iran, as in many other Asian and Middle Eastern countries, some believe that opium has beneficial effects on cardiovascular system. Dependent patients suppose that opium has positive effects on cardiovascular function and can prevent or improve cardiovascular diseases; however, only few comprehensive studies evaluating such effects have been performed. Objectives In this study, we sought to clarify the effect of opium on cardiovascular problems by incorporating the previous findings and the current information on the issue and to explain the possible mechanisms of this effect. Methods The available human studies published up to October 30, 2019, were searched in different databases. Case-control, cohort, and cross-sectional studies were retrieved. Papers published in English or those with an English abstract were included. The risk of bias for each included study was assessed based on the Newcastle-Ottawa Scale (NOS). We then categorized the effects of opium on cardiovascular problems along with its probable underlying mechanisms of action. Results In this study, most of the published articles suggested the adverse effects of opium on the cardiovascular system, including atherosclerosis, myocardial infarction, arrhythmia, low ejection fraction, and cardiovascular mortality; however, some articles reported the beneficial or impartial effects of opium on the cardiovascular system. In this article, we have categorized all the effects of opium on cardiovascular system; also, the proposed mechanisms of action of opium in each of the above-mentioned disorders are summarized. Conclusion Although the available evidences were incoherent, it was mostly suggested that opium use does not protect against or improve cardiovascular problems.