Synthetic drug(seldane) Terfenadine work with histamine

Options

A. inc stimulation of histamine
B. drugs that bind to receptor site & inhibit its natural function
C. inc reactivity of Histamine
D. This drugs mimic that naturl messenger by switching on the receptor

Answer

To solve the question about how the synthetic drug Terfenadine (Seldane) works with histamine, we will analyze the options given and determine which one accurately describes the mechanism of action of Terfenadine.

### Step-by-Step Solution:

1. **Understanding Histamine**:
- Histamine is a chemical in the body that plays a crucial role in allergic reactions. It is released during an allergic response and causes symptoms such as itching, swelling, and redness.

2. **Understanding Terfenadine**:
- Terfenadine is an antihistamine drug used to treat allergic reactions. Its primary function is to counteract the effects of histamine in the body.

3. **Analyzing the Options**:
- **Option A**: "Increases the stimulation of histamine" - This is incorrect because Terfenadine does not increase histamine activity; it works against it.
- **Option B**: "Drug that binds to receptor site and inhibit its natural function" - This is correct. Terfenadine binds to histamine receptors and inhibits their activation by histamine, thereby reducing allergic symptoms.
- **Option C**: "Increases reactivity of histamine" - This is incorrect as Terfenadine does not increase histamine reactivity; it reduces the body's response to histamine.
- **Option D**: "This drug mimics that natural messenger by switching on the receptor" - This is also incorrect. Terfenadine does not mimic histamine; instead, it competes with histamine for binding to its receptors.

4. **Conclusion**:
- Based on the analysis, the correct answer is **Option B**, which states that Terfenadine is a drug that binds to the receptor site and inhibits its natural function.

### Final Answer:
**The correct option is B: Drug that binds to receptor site and inhibit its natural function.**

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