‘Decongestants commonly used by people with allergies, such as pseudoephedrine (eg Actifed) and phenylephrine (eg Sudafed PE), constrict small blood vessels in the nose. Although this eases nasal congestion and improves breathing, the effect isn’t limited to the nose’. Blood vessels all over the body are constricted causing the heart to work that much harder pumping blood all over the body. Excessive use of nasal decongestants can lead to rebound nasal congestion after the decongestant is stopped. And so, one ends up with the same situation they were trying to solve from the beginning plus an elevated blood pressure!  So, if you must, do not use your nasal decongestants for more than three days.

Read! https://www.health.harvard.edu/heart-health/can-allergies-cause-high-blood-pressure