Editing Nicotine (section)

===Cardiovascular system===

Nicotine exerts several significant effects on the [[cardiovascular system]]. Primarily, it stimulates the [[sympathetic nervous system]], leading to the release of [[catecholamine]]s. This activation results in an increase in [[heart rate]] and [[blood pressure]], as well as enhanced [[myocardial contractility]], which raises the workload on the heart.  Additionally, nicotine causes systemic [[vasoconstriction]], including constriction of coronary arteries, which can reduce blood flow to the heart. Long-term exposure to nicotine may impair [[endothelial]] function, potentially contributing to [[atherosclerosis]]. Furthermore, nicotine has been associated with the development of [[cardiac arrhythmia]]s, particularly in individuals who already have underlying heart disease.<ref name="Benowitz 2016" />

The effects of nicotine can be differentiated between short-term and long-term use. Short-term nicotine use, such as that associated with [[nicotine replacement therapy]] (NRT) for smoking cessation, appears to pose little cardiovascular risk, even for patients with known cardiovascular conditions. In contrast, longer-term nicotine use may not accelerate atherosclerosis but could contribute to acute cardiovascular events in those with pre-existing cardiovascular disease.  Many severe cardiovascular effects traditionally associated with smoking may not be solely attributable to nicotine itself. Cigarette smoke contains numerous other potentially cardiotoxic substances, including [[carbon monoxide]] and oxidant gases.<ref name="Benowitz 2016" />

A 2016 review of the cardiovascular toxicity of nicotine concluded, "Based on current knowledge, we believe that the cardiovascular risks of nicotine from e-cigarette use in people without cardiovascular disease are quite low. We have concerns that nicotine from e-cigarettes could pose some risk for users with cardiovascular disease."<ref name="Benowitz 2016">{{cite journal | vauthors = Benowitz NL, Burbank AD | title = Cardiovascular toxicity of nicotine: Implications for electronic cigarette use | journal = Trends in Cardiovascular Medicine | volume = 26 | issue = 6 | pages = 515–523 | date = August 2016 | pmid = 27079891 | doi = 10.1016/j.tcm.2016.03.001 | pmc = 4958544 }}</ref>

A 2018 [[Cochrane (organisation)|Cochrane]] review found that, in rare cases, nicotine replacement therapy can cause non-[[ischemic]] chest pain (i.e., chest pain that is unrelated to a [[myocardial infarction|heart attack]]) and [[heart palpitation]]s, but does not increase the incidence of serious cardiac adverse events (i.e., myocardial infarction, [[stroke]], and [[cardiac death]]) relative to controls.<ref name="Cochrane NRT 2018">{{cite journal | vauthors = Hartmann-Boyce J, Chepkin SC, Ye W, Bullen C, Lancaster T | title = Nicotine replacement therapy versus control for smoking cessation | journal = The Cochrane Database of Systematic Reviews | volume = 5 | pages = CD000146 | date = May 2018 | issue = 5 | pmid = 29852054 | pmc = 6353172 | doi = 10.1002/14651858.CD000146.pub5 | quote = There is high-quality evidence that all of the licensed forms of NRT (gum, transdermal patch, nasal spray, inhalator and sublingual tablets/lozenges) can help people who make a quit attempt to increase their chances of successfully stopping smoking. NRTs increase the rate of quitting by 50% to 60%, regardless of setting, and further research is very unlikely to change our confidence in the estimate of the effect. The relative effectiveness of NRT appears to be largely independent of the intensity of additional support provided to the individual.<br />A meta-analysis of adverse events associated with NRT included 92&nbsp;RCTs and 28&nbsp;observational studies, and addressed a possible excess of chest pains and heart palpitations among users of NRT compared with placebo groups (Mills 2010). The authors report an OR of 2.06 (95%&nbsp;CI 1.51 to 2.82) across 12&nbsp;studies. We replicated this data collection exercise and analysis where data were available (included and excluded) in this review, and detected a similar but slightly lower estimate, OR 1.88 (95%&nbsp;CI 1.37 to 2.57; 15&nbsp;studies; 11,074&nbsp;participants; OR rather than RR calculated for comparison; Analysis 6.1). Chest pains and heart palpitations were an extremely rare event, occurring at a rate of 2.5% in the NRT groups compared with 1.4% in the control groups in the 15&nbsp;trials in which they were reported at all. A recent network meta-analysis of cardiovascular events associated with smoking cessation pharmacotherapies (Mills 2014), including 21&nbsp;RCTs comparing NRT with placebo, found statistically significant evidence that the rate of cardiovascular events with NRT was higher (RR&nbsp;2.29 95%&nbsp;CI 1.39 to 3.82). However, when only serious adverse cardiac events (myocardial infarction, stroke and cardiovascular death) were considered, the finding was not statistically significant (RR&nbsp;1.95 95%&nbsp;CI 0.26 to 4.30). }}</ref>

====Blood pressure====
In the short term, nicotine causes a transient increase in [[blood pressure]]. Long term, epidemiological studies generally show increased blood pressure and [[hypertension]] among nicotine users.<ref name="Benowitz 2016" />