Antihistamines Allergy Medicines are the frequently uses in allergy
Antihistamines Allergy Medicines
Histamine is a biologically active substance that enhances inflammatory and immune responses of the body. It also has physiological function in the gut. Histamine also acts as neurotransmitter. Drugs which that antagonize these effects of histamines are called antihistamines.
Classification of Antihistamines
H1 antihistamines: mostly used to treat allergic disorders and mast cell-mediated disorders.
H2 antihistamines: indicated primarily for gastric reflux disease
H1 antihistamines:
First generation or sedative antihistamines: Have a central effect. They can cause sedatives.
Promethazine
Diphenhydramine
Brompheniramine
Hydroxyzine
Cyproheptadine
Dimenhydrinate
Second generation or less sedative antihistamines
Loratadine
Desloratadine
Cetirizine
Levocetirizine
Fexofenadine
Azelastine
Uses of antihistamines:
Antiallergic agent
Allergic conjunctivitis
Urticaria,
Contact dermatitis
Angioedema
Rhinorrhea
Motion sickness
Antiemetic agent
Side effects of antihistamines
Side effect are more common with first generation antihistamines.
Sedation
Dry mouth
Mydriasis
Dizziness,
Tinnitus,
Urinary retention
Tachycardia
Headaches
H2 antihistamines:
indicated primarily for gastric reflux disease because they reduce the production of stomach acid.
Famotidine
Cimetidine
Ranitidine
Lafutidine
Nizatidine
Roxatidine
