What are the uses of Cimetidine 300mg?

Cimetidine 300mg of Mekophar Chemical - Pharmaceutical Joint Stock Company, the main ingredient is Cimetidine 300mg, is a drug used for short-term treatment of advanced gastric and duodenal ulcers. To better understand what cimetidine 300mg is, what Cimetidine 300mg does, let's learn more in the article below.

Cimetidine medicine has the main ingredient cimetidine 300mg and a sufficient amount of excipients for one tablet. Cimetidine is a stomach acid reducer used to treat and prevent certain types of stomach ulcers. Cimetidine is also used to treat gastroesophageal reflux disease (GERD), when stomach acid backs up into the esophagus and causes heartburn. Over-the-counter (over-the-counter) cimetidine is used to treat heartburn with acidity and acid indigestion or to prevent these conditions when caused by certain foods or drinks. Pharmacodynamics of cimetidine 300mg: Cimetidine is a histamine H2-receptor antagonist, rapidly inhibiting both basal gastric acid secretion and stimulating and decreasing pepsin output. It is a competitive, reversible antagonist and is used as an anti-ulcer drug. It is highly selective in its activity, with almost no effect on histamine H1 receptors, or indeed on receptors for other drugs or autophagy. Despite the wide distribution of H2 receptors in vivo, cimetidine interferes little with physiological functions other than gastric secretion, implying that extragastric H2 receptors are of physiological importance. small.
However, H2 blockers such as Cimetidine inhibit those effects on the cardiovascular and other systems that are stimulated through receptors by exogenous or endogenous histamine, respectively.
Cimetidine inhibits gastric acid secretion induced by histamine or other H2 agonists in a competitive, dose-dependent manner; The degree of inhibition is comparable to that of plasma drug concentrations over a wide range. Additionally, H2 blockers inhibit muscarinic or gastrin-induced gastric secretion, although this effect is not always complete.
This range of inhibitory effects is not due to nonspecific actions at receptors for these secretions. Instead, this effect, non-competitive and indirect, seems to indicate that these two types of secretions use histamine as the final common mediator or, more likely, that the cell's continuous histaminergic stimulation parietal cells are important for amplifying stimuli. provided by ACh or gastrin as they act on their separate receptors. Receptors for all three secretions are present in parietal cells. The ability of H2 blockers to inhibit the response of all three physiological secretions makes them potent inhibitors of all phases of gastric acid secretion. Thus, these drugs will inhibit basal (fasting) and nocturnal secretions and also those stimulated by food, sham feeding, basal stress, insulin or caffeine. H2 blockers reduce both the volume of gastric juice secreted and its hydrogen ion concentration. The output of pepsin, secreted by the main cells of the gastric gland (mainly under cholinergic control), usually decreases in parallel with the decrease in gastric volume. Excretion of intrinsic factor is also reduced, but it is usually greatly secreted and absorption of vitamin B12 is usually adequate even with long-term treatment with H2 blockers.
The concentration of gastrin in the blood plasma is not significantly altered under fasting conditions; however, normal blood gastrin levels may be increased, seemingly as a result of a reduction in the negative feedback normally provided by acid.
Pharmacokinetics of cimetidine 300mg: Cimetidine is rapidly and almost completely absorbed from the gastrointestinal tract. Absorption is less impaired by food or by antacids. Peak plasma concentrations are reached approximately one hour after oral administration in the fasted state and about 2 hours after administration with food. Duration of action is reported to be prolonged when taken with food. Peak plasma concentrations are reached after about 1 to 2 hours. First-pass metabolism in the liver results in a bioavailability for cimetidine of about 60%. The half-life is about 2-3 hours. Cimetidine is eliminated primarily by the kidneys, and 60% or more may appear in the urine unchanged; Most of the rest is oxidation products. Small amounts are recovered in the feces.
Cimetidine crosses the placental barrier and is excreted in milk. It does not easily cross the blood-brain barrier.

Cimetidine is indicated in the treatment of benign and peptic ulcers, including those in combination with non-steroidal anti-inflammatory drugs, recurrent and peptic ulcers, reflux esophagitis and other conditions where The reduction of gastric acid with cimetidine has been shown to be beneficial: persistent dyspeptic symptoms with or without ulceration, particularly meal-related upper abdominal pain, including drug-related symptoms non-steroidal anti-inflammatory; Prophylaxis of gastrointestinal bleeding from stress ulcers in critically ill patients; before general anesthesia in patients thought to be at risk for acid aspiration (Mendelson's syndrome), especially obstetric patients during labor; to reduce malabsorption and fluid loss in short bowel syndrome; and in pancreatic insufficiency to reduce the degradation of enzyme supplements. Cimetidine is also recommended in the treatment of Zollinger-Ellison syndrome, multiple endocrine neoplasia. In addition, Cimetidine is also indicated in the prevention and treatment of gastrointestinal bleeding due to ulcers of the esophagus, stomach or duodenum.
Contraindications of cimetidine 300mg: Do not use cimetidine if you are allergic to cimetidine or other stomach acid reducers such as ranitidine, famotidine, zantac, acid and others.
Ask your doctor and pharmacist before you use cimetidine if:
You have stomach pain, nausea and vomiting; You find it difficult to swallow; You have frequent chest pain; You often have heartburn with wheezing; Unexplained weight loss; Ợ sourness lasts more than 3 months; or Liver or kidney disease. Ask your doctor before using cimetidine if you are pregnant
Do not breastfeed while you are using cimetidine
Do not give this medicine to children without consulting your doctor.

3.1 How to use – dosage of cimetidine 300mg: How to use: Use exactly as directed on the label, or as directed by your doctor.
Cimetidine is usually taken with meals or at bedtime.
Take cimetidine within 30 minutes before eating or drinking to prevent heartburn caused by food or drink.
Take the medicine with a full glass of water.
Measure liquid medicine carefully. Use a specialized measuring device such as a syringe, a medication measuring device (not a kitchen spoon).
It can take up to 8 weeks for an ulcer to heal. Do not stop taking the medicine even if your symptoms improve rapidly. Follow the correct course of medication
If you smoke your ulcers may take longer to heal.
If your symptoms do not improve or they get worse, tell your doctor.
Do not use over-the-counter cimetidine unless directed by your doctor for longer than 14 days.
Recommended dosage: Adults:
+ For patients with gastric and duodenal ulcers: A single dose in the evening at bedtime with a dose of 800mg, taken continuously for at least 4 weeks for duodenal ulcers colon and at least 6 weeks for peptic ulcers. The maintenance dose for this patient was 400 mg/day.
+ For patients with gastroesophageal reflux disease: 4 times a day, from 300-400mg each time, used from 4 to 8 weeks.
+ People with Zollinger-Ellison syndrome: 4 times a day, each time from 300-400mg
+ People with stress causing upper gastrointestinal ulcers: 300mg/time, repeat every 6 hours.
Children over 1 year: Dose from 20 to 30mg/kg/day, divided into 3-4 times.
What to do if overdose? Some symptoms may occur if you overdose such as: pupil dilation, agitation, disorientation, rapid pulse, dysarthria, respiratory failure,...
Immediately go to the nearest medical facility Get prompt treatment if you overdose.
What to do if missed dose? If you miss a dose, take it as soon as you remember, if it is almost time for your next dose, skip the missed dose. Do not take two doses at the same time.
3.2. Warnings/precautions when using cimetidine The dose should be reduced in patients with impaired renal function according to creatinine clearance. The following doses are recommended: Creatinine clearance from 0 to l5ml per minute, 200mg twice daily; 15 to 30ml per minute, 200mg three times a day; 30 to 50ml per minute, 200mg four times a day; over 50 ml per minute, normal dosage. Cimetidine is removed by hemodialysis, but not to a significant extent by peritoneal dialysis.
Clinical trials of six years of 'continuous treatment and more than 15 years' of extensive use have shown no adverse reactions associated with long-term therapy.
The safety of prolonged use is not fully established, and periodic monitoring of patients receiving prolonged treatment is warranted.
It should be noted that patients with a history of peptic ulcer disease, especially the elderly, who are being treated with cimetidine and a non-steroidal anti-inflammatory agent are regularly monitored.
Before initiating treatment with this preparation for any gastric ulcer, malignancy should be excluded by endoscopy and biopsy, if possible, as Cimetidine tablets may relieve symptoms and Help heal the appearance of stomach cancer. The consequences of a delay in diagnosis, especially in middle-aged or older patients, should be noted with new or changed dyspeptic symptoms.
Because of the potential for coumarin interactions, close monitoring of prothrombin time is recommended when cimetidine is co-administered.
Concomitant use of therapeutic agents with a narrow therapeutic index, such as phenytoin or theophylline, may require dose adjustment when starting or stopping concomitant cimetidine.
Lactose: This product contains lactose. Patients should not take this medicine if they have rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
3.3. Side effects of cimetidine If you have signs of a side effect such as an allergic rash, trouble breathing, swelling of your face or throat, a serious skin reaction with symptoms such as fever, burning in your eyes, sore throat, skin pain, red or purple rash that spreads and causes blistering and peeling.
Stop using cimetidine and tell your doctor right away if:
If you have pain when swallowing; stools with blood or tar, cough with bloody sputum, or vomit that looks like coffee grounds; You have mood swings, anxiety, agitation; You are confused, hallucinating; or The breast is swollen and painful. In older people and those who are sick or debilitated, serious side effects are more likely.
Headache or diarrhea are common side effects
The above side effects are not exhaustive, and other undesirable effects may occur. Call your doctor for advice about unwanted effects.
3.4. Drug Interactions Consult a specialist before using cimetidine with any other medicine, especially:
Tell your doctor or pharmacist of all medicines you are taking before using using cimetidine, especially some of the following drugs
Ketoconazole ; Phenytoin; Theophylline; Antidepressants ; or Blood thinners-warfarin, coumadin, jantoven; heart or blood pressure medicine--nifedipine, propranolol; or Sedatives - chlordiazepoxide, diazepam. This list is not exhaustive and many other medicines can affect cimetidine or make it less effective when taken at the same time as cimetidine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.