4.8 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: These drugs are commonly used for symptomatic relief in upper respiratory infections.

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. 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 two hours of bedtime.

Side Effects/Adverse Effects: Alpha-1 agonists can cause headache, bradycardia, excitability, and restlessness. Rebound congestion may occur with nasal sprays.

Health Teaching & Health Promotion: Clients should be instructed to take medication as prescribed and be careful not to double doses. If they experience nervousness, breathing difficulties, or heart rate changes, they should notify their health care provider.^[1]

Now let’s take a closer look at the medication grid on phenylephrine and pseudoephedrine in Table 4.8.^[2]

Table 4.8 Phenylephrine and Pseudoephedrine Medication Grid