Anti-allergic agent

Drugs used to treat allergic reactions

Anti-allergic agents

Anti-allergic agents, also known as antiallergics, are a class of drugs used to prevent or treat allergic reactions. These agents work by various mechanisms to reduce or block the effects of allergens on the body, thereby alleviating symptoms associated with allergic reactions such as itching, swelling, and nasal congestion.

Mechanisms of action

Anti-allergic agents can be classified based on their mechanism of action:

Antihistamines

Antihistamines are the most common type of anti-allergic agents. They work by blocking the action of histamine, a chemical released during an allergic reaction that causes symptoms such as itching, swelling, and redness. Antihistamines are often used to treat conditions like allergic rhinitis, urticaria, and conjunctivitis.

Levocetirizine, a common antihistamine

Mast cell stabilizers

Mast cell stabilizers prevent the release of histamine and other inflammatory mediators from mast cells. These agents are used in the prevention of allergic reactions, particularly in conditions like asthma and allergic conjunctivitis.

Corticosteroids

Corticosteroids are powerful anti-inflammatory agents that reduce inflammation and suppress the immune response. They are used in the treatment of severe allergic reactions and chronic allergic conditions. Corticosteroids can be administered orally, topically, or via inhalation.

Corticosteroids are used to reduce inflammation

Decongestants

Decongestants are used to relieve nasal congestion associated with allergic reactions. They work by constricting blood vessels in the nasal passages, reducing swelling and congestion.

Nasal decongestants help relieve congestion

Common anti-allergic agents

Some commonly used anti-allergic agents include:

• Cetirizine - A second-generation antihistamine used to treat hay fever and urticaria.
• Loratadine - Another second-generation antihistamine with fewer sedative effects.
• Fluticasone - A corticosteroid used in nasal sprays to treat allergic rhinitis.
• Pseudoephedrine - A decongestant often combined with antihistamines in allergy medications.

Zyrtec-D, a combination of cetirizine and pseudoephedrine

Side effects

The side effects of anti-allergic agents vary depending on the class of drug. Common side effects of antihistamines include drowsiness, dry mouth, and dizziness. Corticosteroids can cause weight gain, increased blood pressure, and mood changes with long-term use. Decongestants may cause insomnia, increased heart rate, and elevated blood pressure.

Related pages

• Allergy
• Histamine
• Immune system
• Inflammation