Role of Decongestants in Allergic Rhinitis

By: Nirali Patel PharmD. Rph.

Allergic rhinitis is a common chronic respiratory illness that affects quality of life, productivity, and other comorbid conditions, including asthma. It is an immunoglobulin E–mediated disease, thought to occur after exposure to indoor and outdoor allergens such as dust mites, insects, animal dander, mold, and pollen. Symptoms include rhinorrhea, nasal congestion, obstruction, and pruritus.

Treatment options for allergic rhinitis include oral and topical decongestants which improve the nasal congestion associated with allergic rhinitis by acting on adrenergic receptors, which causes vasoconstriction in the nasal mucosa, resulting in decreased inflammation. The most commonly available decongestants are phenylephrine, oxymetazoline (Afrin), and pseudoephedrine.

Nasal spray decongestants work within about 10 minutes and may provide relief for up to 12 hours. Common adverse effects that occur with the use of intranasal decongestants are sneezing and nasal dryness and nasal bleeding. Therefore, duration of use of nasal decongestants for more than three to five days is usually not recommended, because patients may develop rhinitis medicamentosa or have rebound or recurring congestion. However, a study of 35 patients found no rebound when oxymetazoline was used for 10 days.

Oral decongestants work within 30 minutes and may provide relief for up to 24 hours. Oral decongestants may cause potentially serious adverse effects, such as: headache, elevated blood pressure, tremor, urinary retention, dizziness, tachycardia, anxiety and insomnia. Therefore, patients with underlying cardiovascular conditions, glaucoma, or hyperthyroidism should only use these medications with close monitoring. A study of 25 patients with controlled hypertension provides some reassurance about the use of oral decongestants; compared with placebo, this randomized crossover study found minimal effect on blood pressure with pseudoephedrine use.

In geriatric patients, decongestants should only be considered when congestion is not controlled by other agents.

Caution is advised in patients with diabetes mellitus, ischemic heart disease, unstable hypertension, prostatic hypertrophy, hyperthyroidism, and narrow-angle glaucoma.

Oral decongestants are contraindicated with co-administration with monoamine oxidase inhibitors (MAOIs), and in patients with uncontrolled hypertension, severe coronary artery disease and benign prostatic hyperplasia (BPH).