health

Finding Relief with Antihistamine First-Generation vs. Second-Generation

By Alpro Pharmacy

July 17, 2024

Imagine this: You’re walking at the park on a Sunday morning, the sun is shining, the birds are chirping, the wind is breezing, and everything is perfect—until the pollen attacks. Hachoo!! Suddenly, your nose is leaking, your eyes turn red and watery, and you’re sneezing uncontrollably. Your perfect Sunday morning is now ruined, and you have to rush back home to rest. For those who have experienced something similar to this situation, I assume you’re familiar with the word “antihistamines”. To some people, antihistamines are the heroes of the allergy season. These tiny pills, which look like a grain of rice, sure know how to save your day from worsening. But how does this tiny pill magically solve your allergy symptoms in an hour or so? I bet this question will sometimes cross your mind once.

How does antihistamines work?

In scientific explanation, antihistamines block the effects of histamine. Duh! It’s obvious, right? But what is histamine? The human body is very protective; whenever it detects something harmful, such as infection, it releases histamine through an immune response. This histamine causes our blood vessels to expand and the skin to swell, which helps protect our body through inflammation.

However, in individuals with allergies, the body incorrectly identifies a harmless substance—like pollen, pet hair, or household dust—as a danger and releases histamine in response. The histamine triggers an allergic reaction, leading to uncomfortable symptoms such as itchiness, watery eyes, a runny or congested nose, sneezing, and skin rashes. Thus, antihistamine medication can either stop the reaction if you come into contact with the substance you’re allergic to or reduce your symptoms from worsening. 

Want an easier explanation?

Now imagine your body as a house; those allergens (pollen, dust, or pet’s fur) are uninvited visitors. Your body’s immune system acts like an overprotective security guard who mistakes these harmless visitors for dangerous intruders. To defend the house, the security guard releases histamines, which are like alarm signals that cause all those unpleasant allergy symptoms—itchy eyes, runny nose, sneezing, and more.

Are antihistamines equally the same?

There are two main generations of antihistamines: first-generation and second-generation. As the name suggests, first-generation is the first antihistamines developed and were introduced in the 1940s. Examples of first-generation antihistamines are Diphenhydramine, Chlorpheniramine, and Promethazine. They are effective in treating allergy symptoms such as runny nose, itchiness, rashes, and hives. Besides, it can be used to treat motion sickness due to its sedative effects. The main side effects of first-generation antihistamines are they can cause dry mouth, drowsiness, blurred vision, and dizziness because they can easily cross the blood-brain barrier. Thus, if you’re taking first-generation antihistamines, we advise you to avoid driving vehicles or operating any heavy machinery.  

Second-generation antihistamines were first developed in the 1980s. Second-generation antihistamines focus on overcoming the main drawbacks of first-generation antihistamines, which are drowsiness and sedation. Because second-generation antihistamines are less likely to cross our blood-brain barrier, thus, the side effects are greatly reduced. Example of second-generation antihistamines are Cetrizine, Levocetirizine, Loratadine, Desloratadine, Fexofenadine. These antihistamines are suitable for daytime use and usually has a longer duration of action. Thus, for people who still want to work or do their daily routines, it is advisable to take second-generation antihistamines. 

However, a small subset of people may experience drowsiness even after taking second-generation antihistamines. If it is your first time taking second-generation antihistamine, be alert of the changes in your body and avoid driving if you experience drowsiness/sedation.   

In conclusion, getting a consultation from a doctor or pharmacist is important when deciding on the right antihistamine for your individual needs. We as healthcare professionals are able to give personalized advice based on your symptom’s severity, medical history, and any other medications you may be taking. Besides, we can help you to choose the differences between first-generation and second-generation antihistamines, while considering factors such as potential side effects, the risk of drowsiness, and the duration of relief each antihistamine offers. We are also experienced in detecting possible interactions with other medications and will recommend the most effective and safe treatment for your unique situation. Thus, by seeking our guidance, you ensure that you select an antihistamine that not only alleviates your symptoms but also guarantees your health safety.

Need More Information? Talk to Our Expert!

If you have any questions, please do not hesitate to contact Alpro ePharmacy or visit the nearest Alpro Pharmacy. Our team, consisting of pharmacists, doctors, physiotherapists, nutritionists, audiologists and dietitians, is ready to assist and provide support.

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