Allergies are a common problem worldwide, affecting millions of people every year.

They are an immune response to certain substances called allergens, and the symptoms can vary from mild to severe, including sneezing, itching, coughing, hives, and even anaphylaxis.

The treatment of allergies depends on the severity of the symptoms and the type of allergen. In general, the first line of treatment includes allergen avoidance and medication, such as antihistamines, decongestants, and corticosteroids.

What are antihistamines?

Antihistamines are medications that block the action of histamine, a chemical that is released by the body in response to allergens. Histamine is responsible for causing many of the symptoms of allergies, such as itching, swelling, and redness.

Antihistamines are available in different forms, including tablets, liquids, nasal sprays, and eye drops. They can be classified as first-generation or second-generation antihistamines, depending on their properties and side effects.

How do antihistamines work?

Antihistamines work by binding to histamine receptors in various body tissues, such as the skin, airways, and blood vessels. By blocking the action of histamine, they can reduce the symptoms of allergies, such as itching, sneezing, and runny nose.

They can also prevent the release of other chemicals that contribute to the allergic response, such as leukotrienes and prostaglandins.

What are the types of antihistamines?

: First-generation antihistamines

First-generation antihistamines, also known as sedating antihistamines, were developed in the 1940s and 1950s. They are so called because they can cause drowsiness and other side effects, such as dry mouth, blurred vision, and constipation.

Examples of first-generation antihistamines include:.

Chlorpheniramine
Diphenhydramine
Brompheniramine
Hydroxyzine
Promethazine

First-generation antihistamines are still used in some cases, such as for their sedative properties in patients with insomnia or anxiety. However, they are less commonly used for the treatment of allergies, especially in children and older adults.

: Second-generation antihistamines

Second-generation antihistamines, also known as non-sedating antihistamines, were developed in the 1980s and 1990s. They are so called because they have fewer side effects and are less likely to cause drowsiness than first-generation antihistamines.

Examples of second-generation antihistamines include:.

Cetirizine
Fexofenadine
Loratadine
Desloratadine
Levocetirizine

Second-generation antihistamines are the preferred treatment for allergies, especially seasonal allergic rhinitis and chronic urticaria.

They have a longer duration of action than first-generation antihistamines and are more effective in reducing the symptoms of allergies, such as nasal congestion and eye itching.

How to use antihistamines?

Antihistamines should be used according to the instructions of your healthcare provider or the label of the medication. They are usually taken orally, once or twice daily, with or without food.

Some antihistamines, such as nasal sprays or eye drops, are applied directly to the affected area.

Antihistamines should not be used in larger amounts or for longer than recommended. They can cause side effects, such as drowsiness, dizziness, headache, and dry mouth.

They can also interact with other medications, such as sedatives, antidepressants, and antipsychotics.

Antihistamines are generally safe for most people, including pregnant and breastfeeding women, but they should not be used in infants younger than six months without medical advice.

Conclusion

Antihistamines are an important component in the treatment of allergies. They work by blocking the action of histamine, a chemical that causes many of the symptoms of allergies.

Antihistamines are available in different forms and can be classified as first-generation or second-generation antihistamines, depending on their properties and side effects. Second-generation antihistamines are the preferred treatment for allergies, due to their efficacy and safety profile.

However, antihistamines should be used cautiously and according to the instructions of your healthcare provider or the label of the medication.