Antihistamines

What Are Antihistamines?

Antihistamines are a class of medicine that limits your body’s allergic responses to irritants like pollen, dust, and dander. They block receptors on your cells that cause allergic responses. Some types of antihistamines block multiple types of receptors to target a range of responses, while others only target a single kind of receptor. Histamine proteins communicate with the body by connecting to receptor proteins on the outside of cell walls. Antihistamines block these receptor proteins so histamine molecules can’t make a connection. This prevents the histamine signal from reaching the cells, therefore preventing allergic reactions. Antihistamines reduce the effectiveness of your body’s histamines, which your immune system releases when it encounters allergens and irritants. Histamines also influence your sleep cycle and carry messages between different parts of the body, so it’s normal to have some level of histamines at all times. High histamine levels, such as those released in response to allergens, can cause the following allergy symptoms:

• Itching
• Swelling
• Hives
• Low blood pressure
• Rapid heart rate
• Flushing
• Pain
• Sneezing, coughing, or runny nose
• Bronchoconstriction (tightening of the airways)
• Vasodilation (expansion of blood vessels)

First Generation Antihistamines

First-generation antihistamines bond with histamine receptors as well as muscarinic receptors on cell walls. Muscarinic receptors are involved in a range of processes including bronchodilation, or constricting the lungs and breathing passages. By blocking the muscarinic receptors, first-generation antihistamines may reduce breathing problems like wheezing and shortness of breath. This type of medicine also crosses the blood-brain barrier to interact directly with histamine and muscarinic receptors in the medulla. First-generation antihistamines reduce sneezing, runny nose, mucus, and sometimes cough. They cause side effects including drowsiness, dizziness, headaches, and dry mouth. These medicines are often suggested to relieve cold symptoms. Examples of first-generation antihistamines include:

• Brompheniramine
• Dimenhydrinate
• Diphenhydramine
• Doxylamine
• Chlorpheniramine

Second Generation Antihistamines

Second generation antihistamines primarily bond with histamine receptors, not with muscarinic receptors. They also do not cross the blood-brain barrier so they do not interact with receptors in the brain. Second-generation antihistamines are less effective at relieving symptoms than first-generation antihistamines. However, they also cause fewer side effects. They’re typically prescribed for ongoing preventative allergy relief. Second-generation antihistamines include:

• Loratadine
• Ceterizine
• Desloratadine (Aerius)
• Fexofenadine

Why Are Antihistamines Becoming More Expensive In The USA?

Antihistamine prices have been increasing recently. There are several reasons behind these higher costs. First, “allergy season” is growing longer every year. Plants are producing more pollen because of rising temperatures. Unseasonably warm winters cause plants to start blooming earlier than usual. This causes a rise in outdoor allergy symptoms. The longer outdoor allergy season also causes allergy symptoms to feel worse. Prolonged irritation and inflammation stresses the immune system and makes it hard to recover. This can lead to infections and other illnesses. People are buying more antihistamines in response to the longer allergy season and their more serious symptoms. This new trend causes increased demand, but drug manufacturers can’t make enough antihistamines to keep up. Prices have gone up in response.