High blood pressure

Answered January 09, 2012 06:32. In short -- no. Diet Dots contain an ingredient called synephrine which can cause blood vessel spasm and elevated pulse (to name just 2 side effects). In a bigger sense, diet pills are almost always a bad idea for anyone, but especially for those with a history of heart disease, high blood pressure, and thyroid disease. Bear in mind that there is no evidence that any diet pill, be it over the counter or prescription, has ever been shown to help a person loose weight AND keep it off.