Health Tips

Antihistamines: Do you really know what they are?

“Ugh, this itch here is killing me.”

“This runny nose is annoying!”

“Here you go. Antihistamines for you.”

What exactly are antihistamines? What are they used for? Do different types of antihistamines function differently? Is what I’m taking right now antihistamines?

In this article, we will be explaining what exactly antihistamines are and what their usages are.

What are antihistamines?

Antihistamines are medications used for the relief of allergy reactions like itch, runny nose and sneezing.

It works by blocking histamine in our body which is heightened during an allergic reaction.

Types of antihistamines

1. Oral antihistamines

2. Nasal antihistamines

3. Intraocular antihistamines

Types of oral antihistamines

First generation

1. Chlorpheniramine

2. Diphenhydramine

3. and more

Second generation

1. Cetirizine

2. Levocetirizine

3. Loratadine

4. Desloratadine

5. Fexofenadine

6. Bilastine

7. and more

What are the differences between first and second generation antihistamines?

First generation antihistamines

• The older generation of antihistamines

• More likely to enter brain hence more sedative, may impair cognitive functioning and school performance in children (MIMS)

• Cheaper 

• Short-acting

Second generation antihistamines

• The newer generation of antihistamine

• Less likely to penetrate through brain hence less sedative

• Reasonably priced but slightly more expensive compared to first generation antihistamines

• Long-acting

When to take antihistamines?

• Take your antihistamines according to your doctor/ pharmacist’s instructions

• Can be taken when symptoms arise

• Or taken before exposure to allergens such as pollen, fur etc.

Side effects for antihistamines

• Drowsiness

• Fatigue

• Dry mouth

So, there you go! Now you know a little bit more about antihistamines. They aren’t just for itching! As safe as antihistamines are, do use them wisely. 

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References:

1. Rhinitis - Allergic Treatment | MIMS Malaysia. Accessed May 14, 2021. https://specialty.mims.com/rhinitis%20-%20allergic/treatment

Written By

Ms. See Wen Xin

Reviewed By

Doc2us Medical Board