From the Guidelines
Phenylephrine is the most effective drug that shrinks membranes and causes local vasoconstriction to decrease blood flow in upper respiratory tract infections. This medication is commonly found in over-the-counter nasal decongestants and works by stimulating alpha-adrenergic receptors in blood vessels of the nasal mucosa, causing them to constrict 1. When these blood vessels narrow, there is reduced blood flow to the nasal passages, which decreases swelling, congestion, and mucus production. Typical formulations include nasal sprays (0.25-1% concentration) and oral tablets (10mg), with nasal sprays providing more immediate and targeted relief. However, nasal spray forms should not be used for more than 3-5 days to avoid rebound congestion, as prolonged use can lead to rhinitis medicamentosa 1. Oral forms may be taken every 4-6 hours but have more systemic effects and potentially more side effects including increased blood pressure.
Some key points to consider when using phenylephrine include:
- It is less efficacious compared to pseudoephedrine as an orally administered decongestant due to extensive metabolism in the gut 1
- It should be used with caution in patients with certain conditions, such as arrhythmias, angina pectoris, coronary artery disease, cerebrovascular disease, and hyperthyroidism 1
- It may raise intraocular pressure (IOP) and its efficacy as an oral decongestant has not been well established 1
- Topical decongestants, including phenylephrine, are appropriate for short-term use in nasal congestion associated with acute bacterial or viral infections, exacerbations of allergic rhinitis, and eustachian tube dysfunction 1
Overall, phenylephrine is a useful medication for providing temporary relief of nasal congestion associated with colds, sinusitis, and allergies, but its use should be carefully considered and monitored, especially in patients with certain underlying conditions 1.
From the FDA Drug Label
Purpose: Nasal Decongestant The answer is oxymetazoline (IN), as it is used as a nasal decongestant, which can help shrink membranes and decrease blood flow in the upper respiratory tract, providing relief from congestion 2.
- Key points:
- Nasal decongestant properties
- Used in upper respiratory tract infections
- Shrinks membranes and decreases blood flow
From the Research
Drug Used in Upper Respiratory Tract Infections
- Pseudoephedrine is a drug that shrinks membranes and causes local vasoconstriction, which decreases blood flow, used in the treatment of upper respiratory tract infections 3, 4, 5.
Mechanism of Action
- Pseudoephedrine works by reducing nasal congestion associated with common cold and allergy, and its efficacy has been demonstrated in several studies 3, 4, 5.
Combination Therapies
- Combination therapies of pseudoephedrine with other drugs such as paracetamol or aspirin have been shown to be effective in treating symptoms of upper respiratory tract infections, including nasal congestion and pain-related symptoms 4, 5.
Treatment of Upper Respiratory Tract Infections
- The treatment of upper respiratory tract infections typically involves symptom management with over-the-counter drugs, and pseudoephedrine is one of the commonly used drugs for this purpose 6.