Actions and Uses

Intranasal glucocorticoids are the most effective drugs for prevention and treatment of seasonal and perennial rhinitis. Because of their antiinflammatory actions, these drugs can prevent or suppress the major symptoms of allergic rhinitis: congestion, rhinorrhea, sneezing, nasal itching, and erythema in 90% of patients who use them properly. Seven intranasal glucocorticoids are available (Table 61.2). Three of these—budesonide [Rhinocort Aqua], fluticasone propionate [Flonase], and triamcinolone [Nasacort Allergy 24 hours]−are available in the United States without a prescription. All appear equally effective.

Adverse Effects

Adverse effects of intranasal glucocorticoids are generally mild. The most common are drying of the nasal mucosa and a burning or itching sensation. Sore throat, epistaxis, and headache may also occur.

Systemic effects are possible but are rare at recommended doses. Of greatest concern are adrenal suppression and slowing of linear growth in children (whether final adult height is reduced is unknown). Systemic effects are least likely with ciclesonide, fluticasone, and mometasone, which have very low bioavailability (see Table 61.2).

Preparations, Dosage, and Administration

Intranasal glucocorticoids are administered using a metered-dose spray device. Benefits are greatest when dosing is done daily, rather than irregularly. Full doses are given initially (see Table 61.2). After symptoms are under control, the dosage should be reduced to the lowest effective amount. For patients with seasonal allergic rhinitis, maximal effects may require a week or more to develop. However, an initial response can be seen within hours. For patients with perennial rhinitis, maximal responses may take 2 to 3 weeks to develop. If nasal passages are blocked because of nasal congestion, they should be cleared with a topical decongestant before glucocorticoid administration.

Oral Antihistamines

Oral antihistamines (histamine-1 [H₁] receptor antagonists) are first-line drugs for mild to moderate allergic rhinitis. For therapy of allergic rhinitis, antihistamines are most effective when taken prophylactically and less helpful when taken after symptoms appear.

Preparations, Dosage, and Administration

Dosages for some popular H₁ antagonists are presented in Table 61.3. A more complete list appears in Chapter 54.

TABLE 61.3

Some Antihistamines for Allergic Rhinitis

Generic Name	Trade Name	Dosage
ORAL ANTIHISTAMINES
First Generation (Sedating)
Chlorpheniramine	Chlor-Trimeton Allergy, Chlor-Tripolon , others	Adults and children 12 yr and older: 4 mg every 4–6 hr Children 6–11 yr: 2 mg every 4–6 hr
Diphenhydramine	Benadryl, others	Adults: 25–50 mg every 4–6 hr Children under 10 kg: 12.5–25 mg 3 or 4 times/day
Second Generation (Nonsedating)
Cetirizine*	Zyrtec, Reactine	Adults and children 6 yr and older: 5 or 10 mg once daily
Levocetirizine	Xyzal	Adults and children 12 yr and older: 5 mg once daily Children 6–11 yr: 2.5 mg once daily
Fexofenadine	Allegra	Adults and children 12 yr and older: 60 mg twice daily or 180 mg once daily
Loratadine	Claritin, Alavert	Adults and children 6 yr and older: 10 mg once daily
Desloratadine	Clarinex, Aerius	Adults and children 12 yr and older: 5 mg once daily
INTRANASAL ANTIHISTAMINES
Second Generation (Nonsedating)
Azelastine*	Astelin, Astepro	Adults and children 12 yr and older: 2 sprays/nostril twice daily Children 5–11 yr: 1 spray/nostril twice daily†
Olopatadine	Patanase	Adults and children 12 yr and older: 2 sprays/nostril twice daily (665 mcg/spray)

Intranasal Antihistamines

Two antihistamines—azelastine [Astelin, Astepro] and olopatadine [Patanase]—are available for intranasal administration. Both drugs are indicated for allergic rhinitis in adults and children older than 12 years. Both drugs are supplied in metered-spray devices. The usual dosage is 2 sprays in each nostril twice daily. With both drugs, systemic absorption can be sufficient to cause somnolence. Additionally, some patients experience nosebleeds and headaches with both azelastine and olopatadine. These drugs can also cause an unpleasant taste.

Actions and Uses

For treatment of allergic rhinitis, intranasal cromolyn [NasalCrom] is extremely safe but only moderately effective. Benefits are much less than those of intranasal glucocorticoids. Cromolyn reduces symptoms by suppressing release of histamine and other inflammatory mediators from mast cells. Accordingly, the drug is best suited for prophylaxis and hence should be given before symptoms start. Responses may take a week or two to develop; patients should be informed of this delay. Adverse reactions are minimum—less than with any other drug for allergic rhinitis.

Preparations, Dosage, and Administration

For treatment of allergic rhinitis, cromolyn sodium is available in a metered-dose spray device that delivers 5.2 mg/actuation. The usual dosage for adults and children over 2 years is 1 spray (5.2 mg) per nostril 4 to 6 times a day. If nasal congestion is present, a topical decongestant should be used before cromolyn. Like the antihistamines and glucocorticoids, cromolyn should be dosed on a regular schedule throughout the allergy season.