Patient safety first alert—epinephrine and phenylephrine in surgical settings

AORN Journal,  April, 2003  by Suzanne C. Beyea,  Rodney W. Hicks

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   phenylephrine may be applied first as 1/4 to 1
   percent nose drops or the solutions may be
   mixed and applied together (4 percent lidocaine
   and 1 percent phenylephrine in a 3:1
   combination to yield a 3 percent lidocaine/0.25
   percent phenylephrine solution). (14)

The intranasal application of phenylephrine, however, may result in unpredictable medication absorption. (15) When used as a local vasoconstrictor, a total phenylephrine dose of 2 mg to 4 mg is recommended. Phenylephrine usually is available as a 1% solution containing 10 mg/mL. The maximal total recommended dose of 2 mg is achieved by adding 0.2 mL of 1% solution to the total volume of local anesthetic to be used. (16)

WHAT ARE THE EFFECTS OF RECEIVING TOO MUCH PHENYLEPHRINE?

Phenylephrine can cause restlessness, anxiety, nervousness, weakness, palpitation, tachycardia, premature ventricular contractions, increased perspiration, hypertension, and respiratory distress. Overdose can cause hypertension, headache, seizures, cerebral hemorrhage, palpitations, paresthesia, vomiting, severe bradycardia, and decreased cardiac output. (17)

ARE THERE CERTAIN PATIENTS WHO ARE MORE SENSITIVE TO PHENYLEPHRINE?

Patients taking certain medications, including alpha- and beta-adrenergic blocking agents, oxytocic medications, sympathomimetic agents, general anesthetics, and monoamine oxidase inhibitors are more sensitive. Atropine, digitalis, ergot alkaloids, and diuretics may interact with phenylephrine. (18)

ISSUES SPECIFIC TO THESE MEDICATIONS IN THE OR AND OTHER SURGICAL SETTINGS

Clinicians working the OR and other perioperative settings confront unique practice issues when handling and administering these medications. Problems encountered involve epinephrine and phenylephrine being transferred into unlabeled containers and syringes. Furthermore, both topical and parenteral solutions of these medications are available for use in the OR, and their indications and the correct administration procedures can be misinterpreted easily. Another problematic common practice is that physicians and surgeons may ask to have epinephrine diluted according to their preference for use as an irrigating solution or for injection purposes, which can result in clinicians incorrectly diluting the solution.

Epinephrine and phenylephrine are provided in various concentrations, strengths, and percentages, and their labels may be subject to misinterpretation by clinicians. Epinephrine and phenylephrine may be used for significantly different purposes and in different strengths in the OR, leading to possible misinterpretation when accessing and administering these medications. The fact that in many ORs medications often are chosen from stock supplies without direct pharmacist involvement further contributes to the potential for error.

Epinephrine also is used in local anesthetics, leading to the possibility of misinterpretation of its appropriateness as the right product when a local anesthetic with a dilute solution of epinephrine is indicated. For example, plain epinephrine 1:1,000 may be used when lidocaine with epinephrine 1:100,000 is indicated. Unpredictable absorption rates of both epinephrine and phenylephrine when administered in the nasal submucosal area during surgery also can result in unexpected patient outcomes. (19) There are reports of topical ocular phenylephrine 10% causing adverse effects, including severe hypertension, subarachnoid hemorrhage, and ventricular arrhythmias. (20) These factors, alone or in combination, may result in adverse clinical events.