Problem 12 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Which one of the following is used as Antihistamine? (a) Omeprazole (b) Chloranphenicol (c) Diphenhydramine (d) Norethindrone

Step-by-Step Solution

Answer

Diphenhydramine is used as an antihistamine.

Step 1: Understanding Antihistamines

Antihistamines are drugs used to treat allergic reactions. They work by blocking the action of histamines, which are chemicals released in the body during an allergic reaction, causing symptoms like itching, sneezing, and runny nose.

Step 2: Identifying the Function of Each Option

- Omeprazole is a proton pump inhibitor used to reduce stomach acid. - Chloranphenicol is an antibiotic used to treat bacterial infections. - Diphenhydramine is an antihistamine used to treat allergy symptoms. - Norethindrone is a synthetic hormone used in birth control pills.

Step 3: Selecting the Correct Answer

Based on the functions identified in the previous step, Diphenhydramine is used as an antihistamine to treat symptoms related to allergies.

Key Concepts

Allergic Reactions

Allergic reactions occur when the immune system overreacts to a substance that is normally harmless, known as an allergen. Common allergens include pollen, dust mites, pet dander, and certain foods. The body's defense mechanism mistakenly identifies these substances as threats and releases chemicals like histamines. This release of histamines can cause uncomfortable symptoms:

• Itching
• Sneezing
• Hives
• Swelling
• Runny nose

Understanding these symptoms is crucial for managing allergies effectively. Recognizing the early signs of an allergic reaction can lead to quicker relief with the appropriate medication.

Histamines

Histamines play a central role in the allergic response. They are naturally occurring chemicals in the body that are involved in the immune system's response to foreign invaders. When an allergen enters the body, the immune system releases histamines in large amounts. The effect of histamines in the body can result in:

• Dilation of blood vessels
• Increased mucus production
• Constriction of airway muscles

These responses aim to expel the allergen from the body, but they often lead to uncomfortable symptoms. By blocking histamines' actions, antihistamines can alleviate these allergic symptoms.

Diphenhydramine

Diphenhydramine is a widely used antihistamine. It works by blocking histamines from binding to their receptors in the body, effectively easing the symptoms associated with allergies. Often available over the counter, it is found in many forms such as tablets, capsules, and liquids. Additional benefits of diphenhydramine include:

• Alleviating motion sickness
• Relieving cold symptoms
• Providing mild sedation

It is important to use diphenhydramine as directed, as it can cause drowsiness. Being aware of these side effects helps users avoid activities that require full alertness, such as driving.

Pharmacology

Pharmacology is the branch of science concerned with the study of drugs and their interactions with living organisms. It involves understanding how drugs work, their side effects, benefits, and how they are metabolized by the body. Antihistamines, like diphenhydramine, are a key focus in the pharmacological treatment of allergies. Key aspects of pharmacology include:

• Drug action mechanisms
• Therapeutic effects
• Drug metabolism
• Potential interactions with other drugs

Pharmacologists aim to develop effective medications with minimal side effects. Their research helps ensure that antihistamines are safe and effective for individuals suffering from allergies, enhancing their quality of life.