Which of the following is an antihistamine drug ?

Options

A. Chlorpheniramine
B. Ciprofloxacin
C. Chloramphenicol
D. chloroquine

Answer

To determine which of the given options is an antihistamine drug, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Antihistamine**: Antihistamines are drugs that counteract the effects of histamine in the body. Histamine is a chemical involved in allergic reactions, causing symptoms such as itching, sneezing, and swelling.

**Hint**: Recall that antihistamines are used to treat allergies and related symptoms.

2. **Analyze the Given Options**: We have four options to consider:
- A) Chlorpheniramine
- B) Ciprofloxacin
- C) Chloramphenicol
- D) Chloroquine

**Hint**: List the functions of each drug to identify their categories.

3. **Evaluate Each Option**:
- **Chlorpheniramine**: This is known to be an antihistamine that reduces the effects of histamines, thereby alleviating allergy symptoms.

**Hint**: Look for the drug that specifically mentions its role in treating allergies.

- **Ciprofloxacin**: This is an antibiotic used to treat bacterial infections, not related to histamine.

**Hint**: Antibiotics typically target bacteria, not histamine.

- **Chloramphenicol**: Another antibiotic, used for bacterial infections, not an antihistamine.

**Hint**: Consider the primary use of this drug; it’s not for allergies.

- **Chloroquine**: This medication is primarily used to treat malaria, not allergies or histamine-related conditions.

**Hint**: Remember that malaria treatment does not involve antihistamines.

4. **Conclusion**: Based on the analysis, the only drug that functions as an antihistamine is **Chlorpheniramine**.

**Final Answer**: The correct answer is **A) Chlorpheniramine**.