Why should decongestants such as pseudoephedrine be used cautiously in patients with hypertension or arrhythmias?

• A. They reduce heart rate and blood pressure.
• B. They have no effect on blood pressure.
• C. They can cure hypertension.
• D. They cause alpha-adrenergic vasoconstriction and tachycardia, potentially elevating BP and aggravating arrhythmias.

Answer: (D)

Decongestants like pseudoephedrine are sympathomimetic agents. They work by stimulating alpha-adrenergic receptors in the nasal vasculature to cause local vasoconstriction, but they also increase sympathetic nervous system activity by promoting norepinephrine release. This leads to systemic vasoconstriction and an increase in heart rate (tachycardia). In someone with hypertension, this raises blood pressure further and can worsen cardiovascular risk. In someone with arrhythmias, the added sympathetic drive and faster heart rate can trigger or worsen abnormal rhythms. So the combination of alpha-adrenergic vasoconstriction and tachycardia explains why these drugs should be used cautiously in those patients.

The other statements don’t fit because decongestants do not lower blood pressure or cure hypertension, and they do have a hemodynamic effect—often increasing BP and HR rather than having no effect.