Which of the following can be a result of chronic use of antihistamines?

• A. Increased appetite
• B. Dry mucous membranes
• C. Heightened energy levels
• D. Improved dental hygiene

Answer: (B)

Chronic use of antihistamines can lead to dry mucous membranes, which is a common side effect of these medications. Antihistamines work by blocking the action of histamines, which are substances in the body that cause allergic symptoms. In doing so, they can also inhibit the normal function of bodily secretions, leading to reduced saliva production in the mouth and decreased moisture in mucous membranes throughout the body. This can result in dry mouth, dry nasal passages, and overall dryness of other mucous membranes, potentially leading to discomfort or complications such as oral health issues.

In contrast, while increased appetite, heightened energy levels, and improved dental hygiene are factors that could be mentioned in other contexts, they are not typically associated with the use of antihistamines. Increased appetite is often linked to other medications or conditions, heightened energy levels are generally not a characteristic of these sedating medications, and improved dental hygiene does not result from antihistamine use, as they can actually contribute to oral health problems like dry mouth.