Medications for Allergy

When symptoms of allergic rhinitis require continuous therapy, intranasal corticosteroids are the most effective agents available for nasal symptoms and are more potent than oral antihistamines. Corticosteroids inhibit both the early-phase (cytokine release) and late-phase (migration of mast cells, basophils and eosinophils to the nasal mucosa) allergic reactions. They also decrease microvascular permeability, edema and mucus secretion.

Corticosteroids are available in oral and nasal dosage forms (Table 4). Nasal corticosteroids are effective in reducing congestion, sneezing, rhinorrhea, thick postnasal discharge and nasal pruritus (Table 1) and should be reserved for moderate to severe allergic rhinitis. Their onset of action is not seen until 12 hours after the first dose, with maximal efficacy achieved between three to 14 days of therapy. Side effects with nasal corticosteroid usage are minimal and include nasal irritation, nasal burning and drying. Instructing patients to direct the spray away from the nasal septum can prevent these side effects; however, if a patient develops nasal irritation or bleeding, the nasal steroid should be discontinued. Pharmacists should instruct patients that nasal dryness can be minimized with the use of nasal saline prior to administring the nasal spray. The aqueous nasal corticosteroid preparations (fluticasone propionate, beclomethasone dipropionate, and triamcinolone) are most effective for patients with “drier” noses and predominant nasal congestion. The nonaqueous preparations (beclomethasone, budesonide, triamcinolone acetonide) are most efficacious in patients with rhinorrhea or “wet” noses. At recommended doses, nasal steroids are associated with low systemic absorption, with the exception of dexamethasone sodium phosphate. To maximize effectiveness, treatment with intranasal corti-costeroids should be started prior to allergen exposure and be administered on a regular rather than on an as needed basis. Nasal steroids can be given to patients who should not receive antihistamines or decongestants (e.g., patients with glaucoma, hypertension, prostatic hypertrophy) and the lowest dose that provides relief of symptoms should be used.

A meta-analysis of randomized clinical trials comparing the efficacy of regular-use intranasal corticosteroids to oral antihistamines, supports the superiority of intranasal corticosteroids in relieving nasal congestion, sneezing, postnasal drip and pruritus.A clinical trial comparing the efficacy of as-needed use of loratadine (oral H1 receptor antagonist) with fluticasone propionate (intranasal corticosteroid), showed superiority with the intranasal corticosteroid in the treatment of seasonal allergic rhinitis.

Oral steroids primarily affect the late-phase reaction and because of the risk of systemic effects (adrenal axis suppression, slowed bone growth in children, osteoporosis), should be reserved for patients with severe symptoms that are refractory to intranasal steroids. The corticosteroids of choice are prednisone or methylprednisolone for five to seven days of treatment. Oral steroids should be avoided in patients with hypertension, diabetes, glaucoma and peptic ulcer disease.

This entry was posted on Wednesday, May 4th, 2011 at 8:53 am and is filed under Management of Allergies. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.