What common cold medication can increase blood pressure?

Decongestants, such as pseudoephedrine, work by constricting blood vessels in the nasal passages, which reduces swelling and congestion. This vasoconstriction is effective for alleviating symptoms of nasal congestion but can also lead to increased blood pressure. Pseudoephedrine specifically stimulates alpha-adrenergic receptors, causing blood vessels to narrow and potentially resulting in elevations in blood pressure, especially in individuals who may already have hypertension or are sensitive to these effects.

In contrast, antihistamines primarily target histamine receptors to alleviate allergy symptoms without significantly affecting blood pressure. Antipyretics mainly reduce fever and have little to no impact on vascular tone. Cough suppressants, while they may influence cough reflex and mucus production, do not contribute to changes in blood pressure. Therefore, among the choices, decongestants are the agents clearly associated with an increase in blood pressure.