Pharmacology Eye & Ear Meds #6

Question

The nurse is preparing a patient for cataract surgery and administers phenylephrine hydrochloride drops in the surgical eye prior to the procedure. What is the expected outcome?

Answers

  1. Dilation of the pupil and constriction of the vessels.
    • Rationale:

      This answer is correct because phenylephrine hydrochloride is a mydriatic drug which dilates the pupil. It is used before certain eye surgeries, such as cataract surgery, as a mydriatic drug. The iris is dilated to prevent complications during and after cataract surgery. Phenylephrine hydrochloride also constricts small blood vessels in the eye due to its decongestant action. This action causes the small blood vessels of the eye to constrict, decreasing redness.

  2. Dilation of the pupil and dilation of the vessels.
    • Rationale:

      This answer is not correct because phenylephrine hydrochloride is a mydriatic drug which dilates the pupil; however, it also constricts (not dilates) small blood vessels in the eye. The pupil is dilated to prevent complications during and after cataract surgery.

  3. Constriction of the pupil and constriction of the blood vessels.
    • Rationale:

      This answer is not correct because phenylephrine hydrochloride is a mydriatic eye drop, which means it dilates the pupil. This is done during cataract surgery to help prevent complications during and after the surgery. Phenylephrine hydrochloride is also in the class of medications called decongestants. It causes the small blood vessels of the eye to constrict, decreasing redness.

  4. Constriction of the pupil and dilation of the blood vessels.
    • Rationale:

      This answer is not correct because phenylephrine hydrochloride is a mydriatic drug which dilates the pupil. It is used before certain eye surgeries, such as cataract surgery, as a mydriatic drug. The iris is dilated to prevent complications during and after cataract surgery. Phenylephrine hydrochloride also constricts small blood vessels in the eye due to its decongestant action. This action causes the small blood vessels of the eye to constrict, decreasing redness.

Overview

Phenylephrine hydrochloride is a mydriatic drug which dilates the pupil; however, it also constricts small blood vessels in the eye.

Explanation

The correct answer is A. Phenylephrine hydrochloride is a mydriatic drug which dilates the pupil; however, it also constricts small blood vessels in the eye. The other choices are incorrect.

Learning Outcomes

Phenylephrine hydrochloride is in the class of medications called decongestants. It causes the small blood vessels of the eye to constrict, decreasing redness. It is also used before certain eye surgeries, such as cataract surgery, as a mydriatic drug. Mydriatic drugs dilate the patient’s pupil. It dilates the pupil due to the alpha-adrenergic, sympathetic stimulation of the dilator muscle of the iris. The iris is dilated to prevent complications during and after cataract surgery.

Test Taking Tip

If you get mydriasis and miosis mix up, mydriasis is a larger word compared to the smaller word of miosis, so miosis indicates a smaller pupil (constricted) compared to mydriasis indicating a larger (dilated) pupil.

Video Rationale