Adrenergic Agonists · Pharmacology

Phenylephrine is frequently used as a nasal decongestant. What is its primary mechanism of action?

  1. Beta-2 mediated relaxation of bronchial smooth muscle
  2. Alpha-1 mediated vasoconstriction of nasal mucosa
  3. Inhibition of histamine release from mast cells
  4. Alpha-2 mediated reduction in mucus production
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Correct answer: Alpha-1 mediated vasoconstriction of nasal mucosa

Phenylephrine is a selective Alpha-1 agonist. By causing vasoconstriction of the small blood vessels in the nasal passages, it reduces mucosal edema and congestion.

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