What are common undesirable side effects of decongestants?

Decongestants, commonly used to relieve nasal congestion by constricting blood vessels in the nasal passages, can lead to several undesirable side effects. Shakiness, increased heart rate, and blurred vision are particularly noted among these side effects due to the stimulating effects of many decongestants, which often contain adrenergic agonists. These stimulatory effects can lead to heightened physical responses, such as increased heart rate and sensations of shakiness, as they activate the sympathetic nervous system.

Blurred vision can occur as a result of increased blood pressure and altered blood flow dynamics in the eyes, which may also be influenced by these active ingredients. Understanding these potential side effects is crucial for identifying how decongestants might affect an individual's overall well-being and alertness, especially in contexts that require focus and clear vision.