tyramine
n. a biogenic amine found in high concentrations in a variety of sources, including ripe cheese, broad beans, ergot, mistletoe, some wines, and many foodstuffs that are aged or produced via enzymatic action. Tyramine is derived from the amino acid tyrosine and is sympathomimetic, causing an increase in blood pressure and heart action. Foods containing tyramine react with monoamine oxidase inhibitors, preventing normal metabolism of the tyramine and resulting in significantly elevated blood pressure and possibly a hypertensive crisis.