A 24-year-old man with allergic rhinitis uses an over-the-counter nasal spray containing oxymetazoline, a selective α1-agonist, three times daily for 5 days and develops rebound nasal congestion. On examination, he is hypertensive (BP 148/92 mmHg) and tachycardic (HR 108 bpm). Pupils measure 6 mm bilaterally with intact accommodation. He denies chest pain or dyspnea. Urinalysis shows no glycosuria, and serum electrolytes are within normal limits. Which of the following additional physiologic effects is most likely produced by this drug?
- A)Increased gastrointestinal motility
- B)Detrusor contraction
- C)Decreased peripheral vascular resistance
- D)Bronchoconstriction
- E)Mydriasis without cycloplegiaGABARITO
Explicação
Phenylephrine is a selective alpha 1 agonist that causes vasoconstriction and mydriasis by stimulating the radial muscle of the iris. Because it does not affect muscarinic receptors, it does not cause cycloplegia. Ver explicação completa e trilha adaptativa →