Autonomic Nervous System Regulation
4.9 Alpha-1 Agonists
Pseudoephedrine and phenylephrine are Alpha-1 agonists.
Mechanism of Action: 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.
Indications for Use: These drugs are commonly used for symptomatic relief in upper respiratory infections.
Nursing Considerations Across the Lifespan:
There is limited data on whether pseudoephedrine can be used in children under the age of 4 years old, so it should be avoided. It is safe to use in older adult populations, and no dosage adjustments are required for renal or liver dysfunction.
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. Both should be used cautiously in clients with glaucoma, hypertension, or an enlarged prostate gland and are contraindicated in clients taking monoamine oxidase inhibitors (MAOIs), an older class of medication used to treat depression. Monitor for elevated blood pressure, urinary retention, nervousness, or difficulty sleeping. Do not administer within 2 hours of bedtime.
Patient Teaching & Education: 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.[1]
Phenylephrine and Pseudoephedrine Medication Card
Now let’s take a closer look at the medication grid on phenylephrine and pseudoephedrine in Table 4.9.[2][3] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.
Medication Card 4.9.1: Phenylephrine and Pseudoephedrine
Class: Alpha-1 Agonist
Prototypes: Phenylephrine and Pseudoephedrine
Therapeutic Effects
- hypotension, shock, nasal congestion, decrease secretions
Administration
- PO or IV
- Contraindicated with MAOIs
- Use cautiously in patients with glaucoma, hypertension, or enlarged prostate
Indications
- Hypotension/shock: Treatment of hypotension, vascular failure in shock.
- Hypotension during anesthesia: As a vasoconstrictor in regional analgesia.
- Nasal congestion: As a decongestant.
Side Effects
- hypertension
- urinary retention
- anxiety, dizziness
- dyspnea
Nursing Considerations
- Monitor blood pressure (or mean arterial pressure), heart rate; cardiac output (as appropriate), intravascular volume status, pulmonary capillary wedge pressure (as appropriate);
- monitor infusion site closely
- uCentral from Unbound Medicine. https://www.unboundmedicine.com/ucentral ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- UpToDate (2021). Phenylephrine. https://www.uptodate.com/contents/search ↵