The medications listed can be classified into three main categories: H1-antagonists (antihistamines), H2-antagonists (histamine H2 receptor blockers), and gastric proton-pump inhibitors (PPIs).
Below is a proper classification of antihistamine:
H1-Antagonists (Antihistamines) (Classification of antihistamine):
These are drugs that block the H1 histamine receptor, often used to treat allergic reactions, motion sickness, and as sedatives
A) First-Generation H1-Antagonists:
Diphenhydramine hydrochloride
Dimenhydrinate
Doxylamine succinate
Clemastine fumarate
Diphenylpyraline hydrochloride
Triphelenamine hydrochloride
Chlorcyclizine hydrochloride
Meclizine hydrochloride
Buclizine hydrochloride
Chlorpheniramine maleate
Triprolidine hydrochloride*
Phenidamine tartrate
Promethazine hydrochloride*
Trimeprazine tartrate
Cyproheptadine hydrochloride
Azatidine maleate
B) Second-Generation H1-Antagonists:
Astemizole (discontinued in some regions due to safety concerns)
Loratadine
Cetirizine
Levocetirizine
C) Mast Cell Stabilizer:
Cromolyn sodium (although not a true H1-antagonist, it stabilizes mast cells to prevent histamine release and is often grouped with antihistamines for allergic treatment)
H2-Antagonists (Histamine H2 Receptor Blockers):
These drugs block the H2 histamine receptor, reducing stomach acid production, often used in the treatment of ulcers and gastroesophageal reflux disease (GERD).
Cimetidine
Famotidine
Ranitidine* (discontinued or restricted in many regions due to safety concerns)
Gastric Proton-Pump Inhibitors (PPIs):
These inhibit the proton pump in the stomach, reducing acid secretion, commonly used for GERD, peptic ulcers, and other acid-related disorders.
Omeprazole
Lansoprazole
Rabeprazole
Pantoprazole
This classification separates the drugs based on their mechanism of action and therapeutic use.