Rhinitis medicamentosa (or RM, also known as rebound congestion) is a condition of rebound nasal congestion suspected to be brought on by extended use of topical decongestants (e.g., oxymetazoline, phenylephrine, xylometazoline, and naphazoline nasal sprays) and certain oral medications (e.g., sympathomimetic amines and various 2-imidazolines) that constrict blood vessels in the lining of the nose, although evidence has been contradictory.

[1] The characteristic presentation of RM involves nasal congestion without rhinorrhea, postnasal drip, or sneezing following several days of decongestant use.

[2] Direct acting sympathomimetic amines, such as phenylephrine, stimulate alpha adrenergic receptors, while mixed-acting agents, such as pseudoephedrine can stimulate both alpha and beta adrenergic receptors directly and indirectly by releasing norepinephrine from sympathetic nerve terminals.

Cold turkey is the most effective treatment method, as it directly removes the cause of the condition, yet the time period between the discontinuation of the drug and the relief of symptoms may be too long and uncomfortable for some individuals (particularly when trying to go to sleep when they are unable to breathe through their nose).

A study has shown that the anti-infective agent benzalkonium chloride, which is frequently added to topical nasal sprays as a preservative, aggravates the condition by further increasing the rebound swelling.