True statement about fexofenadine is:
**Core Concept**
Fexofenadine is a **non-sedating antihistamine** used to relieve symptoms of allergic reactions. It works by selectively blocking **histamine H1 receptors**. This mechanism is key to its therapeutic effects.
**Why the Correct Answer is Right**
Since the correct answer option is missing, let's discuss the general properties of fexofenadine. Fexofenadine is known for its selective **H1 receptor antagonism**, which makes it effective in treating allergic rhinitis and urticaria without causing significant sedation. Its pharmacokinetics involves minimal crossing of the **blood-brain barrier**, reducing central nervous system effects.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific option text, we can't directly address why it's incorrect, but generally, incorrect options about fexofenadine might involve misconceptions about its sedative properties or mechanism of action.
**Option B:** Similarly, without the text, we can speculate that if it suggests fexofenadine has significant sedative effects, it would be incorrect due to its known non-sedating profile.
**Option C:** If this option misrepresents fexofenadine's receptor selectivity or its indications, it would be incorrect.
**Option D:** Any option suggesting fexofenadine acts on receptors other than **H1** or implying it has a different primary use would be incorrect.
**Clinical Pearl / High-Yield Fact**
Fexofenadine is a preferred choice for patients who need to avoid sedating antihistamines, such as those operating heavy machinery or requiring mental alertness. Its non-sedating property is a key advantage over first-generation antihistamines.
**Correct Answer:** Correct Answer: D. Fexofenadine is a selective histamine H1 receptor antagonist.