How Do First Generation Antihistamines Work?

antihistamines_first_generation

How They Work
- HOW DO FIRST-GENERATION ANTIHISTAMINES WORK?
Uses
- HOW ARE FIRST-GENERATION ANTIHISTAMINES USED?
Side Effects
- WHAT ARE SIDE EFFECTS OF FIRST-GENERATION ANTIHISTAMINES?
Drug Names
- WHAT ARE NAMES OF FIRST-GENERATION ANTIHISTAMINES?

HOW DO FIRST-GENERATION ANTIHISTAMINES WORK?

First-generation antihistamines are a type of antihistamines that are effective against allergies, colds, and cough.

They work by binding to the histamine receptors in the brain and spinal cord and blocking the release of histamine. Excess release of histamine can cause the following allergic reactions:

Constriction of the bronchial tube
Contraction of smooth muscles
Swelling
Low blood pressure
Depression of the central nervous system
Irregular heart rate

Thus, antihistamines reduce allergic symptoms by preventing the release of histamine. First-generation antihistamines were the first type of antihistamines to be approved by the FDA. The most prominent side effect of first-generation antihistamines is that they cross the blood-brain barrier leading to drowsiness.

HOW ARE FIRST-GENERATION ANTIHISTAMINES USED?

First-generation antihistamines are used for treating:

Allergic reactions
Motion sickness
Insomnia
Anxiety

WHAT ARE SIDE EFFECTS OF FIRST-GENERATION ANTIHISTAMINES?

First-generation antihistamines can cross the blood-brain barrier, leading to a feeling of drowsiness. Other symptoms of first-generation antihistamines include:

Central nervous system depression
Sedation
Muscular weakness
Disturbed coordination
Restlessness
Nausea
Vomiting
Diarrhea
Constipation
Dryness of mouth, nose, and throat
Vertigo
Impotence
Blurred vision
Insomnia
Tremors
Nervousness
Irritability
Chest tightness
Headache
Faintness
Confusion
Disorientation
Itching
Urine retention

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