What are the common side effects of pseudoephedrine?

Pseudoephedrine is an oral decongestant that works by stimulating alpha-adrenergic receptors in nasal blood vessels, causing vasoconstriction and reducing nasal congestion. Common side effects include insomnia, restlessness, nervousness, elevated blood pressure, tachycardia, and headache. It is contraindicated in patients with uncontrolled hypertension, severe coronary artery disease, and those taking monoamine oxidase inhibitors. Pseudoephedrine is kept behind pharmacy counters in the United States because it can be used to manufacture methamphetamine.