4.8 Alpha-1 Agonists V2
Phenylephrine is an alpha-1 agonists. It has a variety of uses, depending on the route of application. Pseudoephedrine is another med in this class, but is seen less often now.
Mechanism of Action
It is a direct acting sympathomimetic acts as an alpha-1 adrenergic receptor agonist.
Nasal congestion: Alpha-1 agonists stimulate alpha receptors in the respiratory tract, causing constriction of blood vessels and shrinkage of swollen nasal mucous membranes, thus increasing airway patency and reducing nasal congestion. For hypotension, vasoconstrictor of veins and arteries to raise mean arterial pressure. For ophthalmic uses, ointment used to facilitate mydriasis and to vasoconstrict conjunctival blood vessels.
Indications for Use
Numerous uses depending on the route. It elevates blood pressure due to vasodilation (septic shock, anesthesia). Also used as a decongestant for sympathomimetic relief in upper respiratory infections, ophthalmic application for mydriasis & to vasoconstrict conjunctival blood vessels. Used in topical application for hemorrhoid relief.
Nursing Considerations
Pseudoephedrine has had recent limitations placed on its use because it is a common ingredient in the illicit manufacturing of the drug methamphetamine. Pharmacies now require individuals to provide identification to purchase pseudoephedrine and must track the number of purchases. As a result, most over-the-counter decongestants now contain phenylephrine.
Monitor for elevated blood pressure, urinary retention, nervousness, or difficulty sleeping.
Do not administer within 2 hours of bedtime.
Pediatrics: There is limited data on whether pseudoephedrine can be used in children under the age of 4 years old, so it should be avoided.
Older adult: It is safe to use in older adult populations, and no dosage adjustments are required for renal or liver dysfunction.
Cautions: Phenylephrine and pseudoephedrine both should be used cautiously in clients with glaucoma, hypertension, or an enlarged prostate gland;
Drug interactions:
- contraindicated in clients taking monoamine oxidase inhibitors (MAOIs), an antidepressant.
Client Teaching
- Clients should be instructed to take medication as prescribed and be careful not to double-dose.
- If they experience nervousness, breathing difficulties, or heart rate changes, they should notify their healthcare provider.
- This med has numerous drug Interactions, ensure to consult with your prescriber if there is any change in your medications.
Phenylephrine Medication Card
Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.
Downloadable file (.docx): Phenylephrine and Pseudoephedrine Medication Card
