What adverse effect is commonly associated with intranasal antihistamines?

Intranasal antihistamines are specifically designed to relieve symptoms of allergic rhinitis by blocking histamine receptors in the nasal passages. A common adverse effect associated with their use is a bitter taste. This phenomenon can occur because when the medication is sprayed into the nasal cavity, it can drain down the back of the throat (post-nasal drip), leading to a taste sensation that many patients describe as unpleasant or bitter.

This side effect is particularly relevant for patients who may be sensitive or averse to certain tastes, impacting their adherence to the medication regimen. While other side effects can occur, the bitter taste is notably more prevalent and recognized among users of intranasal antihistamines, distinguishing it as a key consideration in their therapeutic use.