Generic Name: Cimetidine

  • What is Cimetidine?

    Cimetidine is used to treat certain kinds of stomach and intestinal ulcers and related conditions. These related conditions include active duodenal (upper intestinal) ulcers; active benign stomach ulcers; erosive gastroesophageal reflux disease (backflow of acidic stomach contents); excess acid conditions such as Zollinger-Ellison syndrome (a form of peptic ulcer with too much acid); and prevention of upper abdominal bleeding in those who are critically ill.

    Cimetidine is also used for maintenance therapy of duodenal ulcer after active ulcers are healed.

    There is also an over-the-counter (OTC) version of the drug used to relieve heartburn, indigestion, and sour stomach.

  • What is the most important information I should know about Cimetidine?

    Short-term treatment with cimetidine can result in complete healing of a duodenal ulcer. However, the ulcer can reappear after cimetidine has been stopped. The rate of ulcer recurrence may be slightly higher in people healed with cimetidine rather than other forms of therapy. However, cimetidine is usually prescribed for more severe cases.

    Reversible states of confusion may occur, especially in severely ill patients. Patients >50 years old or with liver and kidney disease may be at greater risk. Discontinuation of cimetidine may be necessary.

    Rare cases of irregular heart rhythm and low blood pressure have been reported after rapid administration of intravenous cimetidine.

    Stop using OTC cimetidine if your heartburn continues or gets worse, stomach pain continues, or you need to take it for more than 14 days.

  • Who should not take Cimetidine?

    Do not use cimetidine if you are allergic to the active ingredient, cimetidine, or any other ingredient in it.

    Do not use OTC cimetidine if you have trouble or pain swallowing food, vomiting with blood, or bloody or black stools.

  • What should I tell my doctor before I take the first dose of Cimetidine?

    Tell your doctor about all prescription, OTC, and herbal medications you are taking before beginning treatment with cimetidine. Also, talk to your doctor about your complete medical history, especially if you have kidney or liver disease, chronic lung disease, diabetes, or a weakened immune system. Ask your doctor before using OTC cimetidine if you have: frequent chest pain; frequent wheezing, particularly with heartburn; unexplained weight loss; nausea or vomiting; stomach pain; had heartburn >3 months; heartburn with lightheadedness, sweating, or dizziness; or chest pain or shoulder pain with shortness of breath, sweating, pain spreading to the arms, neck, or shoulders.

  • What is the usual dosage?

    The information below is based on the dosage guidelines your doctor uses. Depending on your condition and medical history, your doctor may prescribe a different regimen. Do not change the dosage or stop taking your medication without your doctor's approval.

    Active Benign Gastric Ulcer

    Adults: The usual dose is 800 milligrams (mg) once a day at bedtime or 300 mg taken four times a day with meals and at bedtime.

    Active Duodenal Ulcer

    Adults: The usual dose is 800 mg once daily at bedtime. Other effective doses include 300 mg four times a day with meals and at bedtime or 400 mg twice a day, in the morning and at bedtime. Most people heal in 4 weeks. If you require maintenance therapy, the usual dose is 400 mg at bedtime.

    Erosive Gastroesophageal Reflux Disease (GERD)

    Adults: The usual dosage is 1,600 mg daily divided into doses of 800 mg taken twice a day, or 400 mg taken four times a day, for 12 weeks.

    Pathological Hypersecretory Condition (eg, Zollinger-Ellison Syndrome)

    Adults: The usual dose is 300 mg taken four times a day with meals and at bedtime. Your doctor may adjust your dose based on your needs, but you should take no more than 2,400 mg per day.

    Relief or Prevention of Heartburn

    For relief, take one tablet of OTC cimetidine with a glass of water. For prevention, take it 30 minutes before eating or drinking anything that may cause heartburn. Do not take more than two tablets in 24 hours.

    Safety and effectiveness have not been established in children <16 years of age.

    Cimetidine Injection may be used in hospitalized patients. Your doctor will prescribe the appropriate dose for you.

  • How should I take Cimetidine?

    You can take cimetidine with or between meals. Do not take antacids within 1-2 hours of taking a dose of cimetidine.

    It may take several days for cimetidine to begin relieving stomach pain. Be sure to continue taking the drug exactly as prescribed even if it seems to have no effect.

    If you need to take an antifungal drug such as ketoconazole, you should take it at least 2 hours before you take cimetidine.

  • What should I avoid while taking Cimetidine?

    Antacids may be needed for pain relief; however, avoid taking antacids at the same time as oral cimetidine. Antacids can reduce the effect of cimetidine when taken at the same time.

    Ulcers may be more difficult to heal if you smoke.

    Avoid excessive amounts of caffeine while taking cimetidine.

    Avoid alcoholic beverages while taking cimetidine. This drug increases the effects of alcohol.

  • What are possible food and drug interactions associated with Cimetidine?

    If cimetidine is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining cimetidine with the following: antidiabetes drugs, antifungal drugs, amoxicillin, antiarrhythmics, aspirin, benzodiazepine tranquilizers, blood pressure drugs, blood thinners (like warfarin), chlordiazepoxide, chlorpromazine, cisapride, cyclosporine, diazepam, digoxin, ketoconazole, lidocaine, metoclopramide, metronidazole, narcotic pain relievers, nicotine, nifedipine, paroxetine, phenytoin, propanolol, quinine, sucralfate, theophylline, or tricyclic antidepressants.

  • What are the possible side effects of Cimetidine?

    Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking this drug.

    Side effects may include: headache, breast development in men

  • Can I receive Cimetidine if I am pregnant or breastfeeding?

    The effects of cimetidine during pregnancy have not been adequately studied. Tell your doctor immediately if you are pregnant, plan to become pregnant, or are breastfeeding.

  • What should I do if I miss a dose of Cimetidine?

    If you miss a dose of cimetidine, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not take two doses at once. If you are unsure, ask your doctor or pharmacist for advice.

  • How should I store Cimetidine?

    Store at room temperature in a tightly closed container, away from light.

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