Sympathomimetics and Nasal Congestion

• Sympathomimetics reduce nasal congestion from allergic rhinitis, sinusitis, and the common cold, but do not help with sneezing, itching, or allergic rhinitis.
• Phenylephrine is the prototype sympathomimetic medication.
• Pseudoephedrine and ephedrine are other sympathomimetic medications, though their use is limited due to abuse potential.

Pharmacologic Action

• Sympathomimetics activate alpha1-adrenergic receptors in the nose, mimicking the sympathetic nervous system.
• This activation causes vasoconstriction and shrinks nasal turbinates, opening nasal passages to relieve congestion.
• Topical sympathomimetics provide quick relief, but overuse can cause rebound congestion, requiring more frequent use.

Adverse Drug Reactions

• Side effects stem from adrenergic receptor stimulation.
• Oral administration can cause CNS stimulation, leading to agitation, anxiety, and insomnia.
• Systemic vasoconstriction may result in hypertension, arrhythmias, and heart palpitations.
• Pseudoephedrine and ephedrine have abuse potential.
• Overuse of nasal applications can lead to rebound congestion.

Interventions

• Administer sympathomimetics only when necessary due to side effects and rebound congestion from prolonged use as an intranasal decongestant.
• Monitor for agitation, anxiety, and insomnia due to CNS stimulation.
• Increased heart rate, blood pressure, and palpitations may indicate overdosage.
• Recommend a nasal glucocorticoid when discontinuing intranasal sympathomimetics after prolonged use to minimize rebound congestion.
• Inform clients taking pseudoephedrine or ephedrine about the risk for abuse and the importance of adhering to dosage and therapy length.

Safety Alert

• Sympathomimetic medications can increase heart rate and blood pressure.
• Clients with cardiac dysrhythmias, hypertension, or coronary artery disease should be monitored and may need to discontinue use if blood pressure rises or dysrhythmias occur.

Administration

• Do not exceed the recommended dose of oral sympathomimetics.
• Advise clients to take medication only when necessary to prevent overstimulation and CNS side effects.
• Limit topical sympathomimetic use to 3 to 5 days to avoid rebound congestion.

Client Instructions

• Notify the provider of excessive CNS stimulation symptoms like agitation, anxiety, or insomnia.
• Short-term use of a hypnotic or sleep aid may be necessary, or consider alternative medication.
• Report prolonged tachycardia or heart palpitations, which may indicate overdosage.
• Avoid using nasal preparations for more than 3 to 5 days due to the risk of rebound congestion.
• When discontinuing intranasal preparations, taper use by extending the time between administrations, or use the medication in one nostril while the other recovers.
• Regularly check blood pressure for clients with hypertension taking sympathomimetics.

Contraindications and Precautions

• Contraindicated for chronic rhinitis due to not being designed for long-term use.
• Pseudoephedrine and ephedrine are contraindicated due to high risk for abuse.
• Contraindicated in clients with narrow-angle glaucoma, uncontrolled heart disease, hypertension, or dysrhythmia.
• Administer cautiously in clients with coronary artery disease or hypertension.
• Over-the-counter medications must provide a written warning label.
• Use caution in older adults due to vasoconstrictive effects and potential for decreased excretion.

Interactions

• MAOI antidepressants potentiate sympathomimetics; avoid giving within 3 weeks of each other.
• Beta2-adrenergic agonists and other stimulants potentiate hypertensive effects.

Sympathomimetics, like phenylephrine, reduce nasal congestion by activating alpha1-adrenergic receptors, causing vasoconstriction in nasal turbinates. Topical application offers rapid relief, but overuse may lead to rebound congestion. Oral administration can cause CNS stimulation and systemic vasoconstriction, resulting in hypertension and arrhythmias.