How Do Second Generation Antihistamines Work?

Second-generationantihistaminesare a type of antihistamines that are used for treating allergies anditching.

They work by binding to thehistaminereceptorsinthebrainandspinal cordand blocking the release of histamine. Excess release of histamine can cause the following allergic reactions:

• Constriction of the bronchialtube
• Contractionof smooth muscles
• Swelling
• Low blood pressure
• Depressionof thecentral nervous system
• Irregularheart rate

Thus, antihistamines reduce allergic symptoms by preventing the release of histamine. Second-generation antihistamines were the second type of antihistamines to be approved by theFDAbecause they are considered to be safer than first-generation antihistamines. These drugs fail to cross theblood-brain barrierand therefore do not cause drowsiness caused by first-generation antihistamines.

Second-generation antihistamines are used for treating:

• Allergic reactions
• Itchyskin
• Dermatologicconditions

Second-generation antihistamines can cause the following side effects:

• Sleepiness
• Headache
• Fatigue
• Dry mouth
• Dizziness
• Diarrhea
• Malaise
• Vomiting
• Stomachpain
• Drowsiness
• Fussiness
• Hallucinations
• Lowblood pressure
• Tremors
• Tonguediscoloration
• Irritability
• Upperrespiratorytractinfection
• Cough
• Redness
• Rash

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with yourdoctororpharmacistto make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking yourmedicationand never change your dose or frequency without consulting your doctor.

Genericand brand names of second-generation antihistamines include:

• Alavert
• Allegra
• AllegraAllergy12 Hour
• Allegra Allergy 24 Hour
• Aller-Tec
• Cetirizine
• Children's Allegra Allergy
• Children'sZyrtecAllergy
• Children's ZyrtecHivesRelief
• Clarinex
• Clarinex reditabs
• 他定
• 比如reditabs
• Desloratadine
• Fexofenadine
• Levocetirizine
• Loratadine
• Mucinex Allergy
• Pediacare Children's 24 Hour Allergy
• Qlearquil所有Day & All Night 24 Hour Allergy Relief
• Quzyttir
• Wal-Zyr
• Xyzal
• Xyzal Allergy 24HROralSolution
• Xyzal Allergy 24HR Tablets
• Zyrtec
• Zyrtec Allergy