Cimetidine and ranitidine are both H₂ receptor antagonists, the difference between the two drugs is the mechanism of action, clinical indications and drug excretion pathways are different.
1. Cimetidine: a generation of H₂ receptor antagonist, the chemical structure of imidazole, can selectively act on the H₂ receptor. It is mainly used for the treatment of peptic ulcer, reflux esophagitis, stress ulcer, etc. It can also be used to relieve stomach pain, heartburn and acid reflux caused by excessive stomach acid.
Cimetidine is mainly excreted through the liver, and adverse reactions include diarrhea, elevated transaminases, and dizziness. It is contraindicated for those who are allergic to the drug.
2. Ranitidine: it is the second generation of H₂ receptor antagonist, the chemical structure is furan, can competitively block histamine and H₂ receptor binding, its acid inhibition effect is 5-12 times stronger than cimetidine, and has a certain gastric mucosal protection. It can be used to treat peptic ulcer, reflux esophagitis and upper gastrointestinal bleeding.
Ranitidine is mainly excreted through the kidneys, and adverse reactions include arrhythmia, abdominal pain, constipation, diarrhea, nausea, and vomiting. It is contraindicated in patients with dysphagia or pain, vomiting with blood, blood in stool or black stool, and used with caution in patients with renal disease.
The above is the main difference between cimetidine and ranitidine, the specific use of drugs need to consult a professional gastroenterologist’s diagnosis and treatment recommendations.