Nicotine: An alkaloid (a nitrogen-containing chemical) made by the tobacco plant or produced synthetically. Nicotine has powerful pharmacologic effects (including increased heart rate, heart stroke volume, and oxygen consumption by the heart muscle), as well as powerful psychodynamic effects (such as euphoria, increased alertness, and a sense of relaxation). Nicotine is also powerfully addictive.
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Last Editorial Review: 5/13/2016