Review Question - QID 100593

The most likely complication of chronic topical nasal decongestant use is persistent congestion due to drug tachyphylaxis.

Overuse of topical nasal decongestants (alpha-adrenergic agonists that work by causing nasal mucosa vessel constriction) can result in tachyphylaxis. Tachyphylaxis is a diminished effect of the drug due to negative feedback resulting in decreased norephinephrine synthesis and secretion. When used briefly (<3–5 days consecutively), a-adrenergic decongestants provide fast and effective relief of nasal congestion. However, with chronic use, rebound nasal congestion can occur and can be severe. This phenomenon is known as rhinitis medicamentosa.

In order to answer this question, you only need to know a few fundamental concepts about infection/inflammation and drug desensitization. The question stem provides the function of a drug that is being used to manage seasonal allergies, namely vasoconstrictors. Since swelling is a function of vasodilation or "leaky vessels" related to infection or inflammatory response, the objective of this medication is to stop the swelling that results in congestion. Constricting the blood vessels will limit the blood flow to the area and thus the "leakiness" of the vessels reducing the swelling and thus resolving the congestion. The nature of topical vasoconstrictors is such that they do not impact systemic hypertension. Vasoconstriction reduces blood flow and thus epistaxis is not an issue, nor do they act on or impact the cribiform plate. Patients may develop tolerance to any medication, and so the only answer remaining is "rebound" or persistent congestion, the exact opposite of the desired effect.

Illustration A is shows an example of rhinitis medicamentosa. Note the erythematous nasal mucosa.

Incorrect Answer:
Answer 1: Epistaxis, or nose-bleeding, would likely be relieved by intranasal vasoconstrictors.
Answer 2: Hypertension is not a potential complication, as intranasal absorption is not significant enough to affect the systemic vasculature.
Answer 3: Permanent loss of smell is a potential complication of high dose intranasal zinc administration.
Answer 4: Persistent nasal crusting would not be expected as a consequence of chronic topical nasal decongestants.

Congestion is one of the most frequent complaints related to the common cold, for which topical (intranasal) and oral nasal decongestants have been shown to be effective in relieving nasal symptoms in adolescents and adults. Current recommendations state to limit use to three days so as to prevent tachyphylaxis (1).