The choice of drugs for treatment of allergic rhinitis depends on the severity of symptoms and whether they are intermittent or persistent (see Table 1).

Patients with seasonal allergies often experience nasal itching and congestion, sneezing, rhinorrhea, and itchy, watery eyes. Oral, intranasal, and ophthalmic preparations are widely available over the counter (OTC) for relief of symptoms. Prescription products for management of allergic rhinitis and allergic conjunctivitis are reviewed separately.

The FDA has approved the selective alpha_1A-adrenergic receptor agonist oxymetazoline as a 1% cream (Rhofade – Allergan) for topical treatment of persistent facial erythema of rosacea in adults. Brimonidine, a selective alpha₂-adrenergic receptor agonist, was approved in 2013 as a 0.33% gel (Mirvaso) for the same indication. Like Mirvaso, Rhofade is not indicated for treatment of inflammatory lesions of rosacea. Oxymetazoline has been available over the counter for many years as a nasal decongestant spray (Afrin, and others).

Allergic rhinitis can be classified as seasonal, perennial, or episodic. It is often associated with allergic conjunctivitis, rhinosinusitis, and asthma.

H₁-ANTIHISTAMINES — Oral – Oral second-generation H₁-antihistamines are the preferred first-line treatment for relief of the itching, sneezing, and rhinorrhea that characterize mild-to-moderate allergic rhinitis. They are less effective for nasal congestion.

In 2007, an FDA advisory committee asked that placebo-controlled, dose-ranging trials be conducted to establish the efficacy of the oral decongestant phenylephrine (Sudafed PE, and others), which is sold over the counter (OTC) as a single agent and in combination with other drugs for treatment of cold and allergy symptoms. Phenylephrine replaced pseudoephedrine (Sudafed, and others) in many OTC formulations when access to pseudoephedrine-containing products was restricted in an effort to reduce their use in the synthesis of methamphetamine.

CLINICAL STUDIES — In a randomized, open-label, dose-ranging trial in 539 patients with seasonal allergic rhinitis, phenylephrine doses up to four times the recommended dose of 10 mg were no more effective than placebo in reducing symptomatic nasal congestion.1 Other recent studies have also found oral phenylephrine no more effective than placebo in reducing nasal congestion.2-4

ALTERNATIVES – Oral pseudoephedrine reduces nasal congestion, but has no effect on other symptoms such as sneezing, itching, or rhinitis, and tolerance to its effects can occur with repeated use. Potential adverse effects include insomnia, excitability, headache, nervousness, anorexia, palpitations, tachycardia, arrhythmias, hypertension, nausea, vomiting, and urinary retention. Pseudoephedrine should be used cautiously in patients with cardiovascular disease, hypertension, diabetes, hyperthyroidism, narrow-angle glaucoma, or bladder neck obstruction.

Intranasal decongestants such as oxymetazoline (Afrin, and others) are effective and less likely than pseudoephedrine to cause systemic adverse effects, but they can cause stinging, burning, sneezing, dryness of the nose and throat, and, if used for more than 3-5 consecutive days, rebound congestion (rhinitis medicamentosa). Intranasal corticosteroids are the most effective drugs available for prevention and relief of nasal congestion and other seasonal allergic rhinitis symptoms.5

CONCLUSION — Oral phenylephrine is not effective for treatment of nasal congestion.

1. EO Meltzer et al. Oral phenylephrine HCl for nasal congestion in seasonal allergic rhinitis: a randomized, open-label, placebo-controlled study. J Allergy Clin Immunol Pract 2015; 3:702.
2. EO Meltzer at al. Phenylephrine hydrochloride modified-release tablets for nasal congestion: a randomized, placebo-controlled trial in allergic rhinitis patients. Ann Allergy Asthma Immunol 2015 November 7 (epub).
3. F Horak et al. A placebo-controlled study of the nasal decongestant effect of phenylephrine and pseudoephedrine in the Vienna Challenge Chamber. Ann Allergy Asthma Immunol 2009; 102:116.
4. JH Day et al. Efficacy of loratadine-montelukast on nasal congestion in patients with seasonal allergic rhinitis in an environmental exposure unit. Allergy Asthma Immunol 2009; 102:328.
5. Drugs for allergic disorders. Treat Guidel Med Lett 2013; 11:43.

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