I take beta blockers and synthroid, (thyroxine) is it ok to take phenylephrine if i have a cold?

Avoid it: Oral nasal decongestants, such as sudafed (pseudoephedrine) and sudafed pe (phenylephedrine), can increase blood pressure by increasing your heart rate and by causing blood vessels to narrow, also known as vasoconstriction. These effects are greater with immediate release products and higher doses. Pseudoephedrine and phenylephedrine can also be found in many cold, cough, and flu medicines.