Contac® Cold + Flu advises patients suffering from heart disease, high blood pressure and/or diabetes to consult with their doctor before using Contac. Decongestants in cold medicines decrease the size of enlarged blood vessels in nasal passages, but they can also affect blood vessels in the rest of your body and raise blood pressure.
For most people, this increase isn’t significant. However, some people (especially those who already have high blood pressure) can have exaggerated responses to decongestants, contributing to dangerously high blood pressures.
As stated on the label, check with your doctor before using Contac® Cold + Flu if you have liver disease, heart disease, thyroid disease, diabetes, glaucoma, high blood pressure, trouble urinating due to an enlarged prostate gland (if male), or a breathing problem such as emphysema or chronic bronchitis.