Decongestants have a number of side effects on the body. One of most commonly observed side effects of this medication is an increased blood pressure. This is because most of the nasal decongestants show their efficacy by constricting the blood vessels in the nasal cavity. This tends to reduce the size of the swollen blood vessels and allow the normal passage of the air. It is but obvious that when these medicines shrink the size of blood vessels, the rate of heart beat also increases. Consequently, a higher heart beat rate leads to high blood pressure. This is the reason why this medicine must be avoided by heart patients and pregnant women.

Decongestants are both prescription based and over-the-counter medicines. They are potent ant-inflammatory drugs popularly used for allowing easy breathing. These medicines when consumed on regular basis and large quantities considerably decrease the function of the kidneys. This imposes greater stress levels on the kidneys and heart. As a result, the blood pressure rises higher.  Some of the most popular decongestants known for increasing the blood pressure as one of their side effects are oxymetazoline hydrochloride, phenylephrine hydrochloride and pseudoephedrine hydrochloride. These medicines are available in form of nose drops, nasal sprays, tablets and liquids.