The difference between ranitidine and cimetidine can be illustrated in terms of pharmacodynamics, pharmacokinetics, and side effects. 1. Pharmacodynamics: both drugs have the effect of inhibiting gastric acid, but the acid-suppressing effect of ranitidine is much higher than that of cimetidine at the same dosage, and it is a potent Hâ‚‚ receptor blocker. Both drugs are commonly used in the treatment of gastric ulcer, hyperacidity, duodenal ulcer and other diseases. 2. Pharmacokinetics: Both drugs are generally taken orally and absorbed from the digestive tract. Ranitidine is mostly excreted from the kidneys in its original form, with 45% of the administered dose excreted in the urine over 24h. Cimetidine is also excreted through the kidneys, the difference is that cimetidine is a hepatic enzyme inhibitor, so it will interfere with the biotransformation of drugs that rely on hepatic enzymes for metabolism, such as warfarin, in the body. 3. Side effects: Generally speaking, Ranitidine is smaller than Cimetidine, but it is still necessary to choose the appropriate drug treatment according to the patient’s condition. Both of the above drugs need to consult a physician before use, not self-medication.