Cimetidine - oral
Cimetidine - oral
Cimetidine is used to treat ulcers of the stomach and intestines and prevent them from coming back after they have healed. This medication is also used to treat certain stomach and throat (esophagus) problems caused by too much stomach acid (such as Zollinger-Ellison syndrome, erosive esophagitis) or a backward flow of stomach acid into the esophagus (acid reflux disease/GERD). Decreasing extra stomach acid can help relieve symptoms such as stomach pain, heartburn, difficulty swallowing, cough, and trouble sleeping. It can also prevent serious acid damage to your digestive system (such as ulcers, cancer of the esophagus).
Cimetidine belongs to a class of drugs commonly called H2 blockers. It works by reducing the amount of acid in your stomach.
This medication is also available without a prescription. It is used to treat occasional heartburn caused by too much acid in the stomach (also called acid indigestion or sour stomach). It is also used to prevent heartburn and acid indigestion caused by certain foods and beverages. If you are taking this medication for self-treatment, it is important to read the manufacturer's package instructions carefully so you know when to consult your doctor or pharmacist. (See also Precautions.)
Take this medication by mouth with or without food as directed by your doctor.
The dosage and length of treatment are based on your medical condition and response to therapy. Follow your doctor's instructions carefully. If you are also taking antacids to relieve stomach pain as recommended by your doctor, separate them from this medication by at least 1 hour.
Take this medication regularly as prescribed in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose or take it more often than directed. Continue to take this medication for the prescribed length of treatment even if you are feeling better. Stopping treatment too early may delay the healing process.
If you are using nonprescription cimetidine for self-treatment of acid indigestion or heartburn, take 1 tablet by mouth with a glass of water as needed. To prevent heartburn, take 1 tablet by mouth with a glass of water right before or up to 30 minutes before eating food or drinking beverages that cause heartburn. Do not take more than 2 tablets in 24 hours unless directed by your doctor. Do not take for more than 14 days in a row without talking with your doctor.
Inform your doctor if your symptoms do not improve or if they worsen.
Headache, dizziness, drowsiness, or diarrhea may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
If your doctor has directed you to use this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including:
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking cimetidine, tell your doctor or pharmacist if you are allergic to it; or to other H2 blockers (such as famotidine, nizatidine, ranitidine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of:
Some symptoms may actually be signs of a more serious condition. Get medical help right away if you have:
In addition, before you self-treat with this medication, get medical help right away if you have any of these signs of a serious condition:
This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).
Do not use this medication to treat children younger than 12 unless directed by the doctor.
Older adults may be more sensitive to the side effects of this drug, especially confusion and lung infection (pneumonia). Confusion can increase the risk of falling.
During pregnancy, cimetidine should be used only when clearly needed. Discuss the risks and benefits with your doctor.
Cimetidine passes into breast milk. Consult your doctor before breast-feeding.
See also How to Use section.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.
Some products that may interact with this drug include:
This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include fezolinetant, metoprolol, propranolol, tacrine, warfarin, zaleplon, calcium channel blockers (such as diltiazem), tricyclic antidepressants (such as amitriptyline), theophylline, among others.
Since cimetidine reduces the amount of acid in your stomach, it may also change the absorption of certain medications and affect how they work. Some examples of affected drugs include atazanavir, dasatinib, certain azole antifungals (such as itraconazole, ketoconazole), levoketoconazole, pazopanib, sparsentan, among others. Ask your doctor or pharmacist if any of the medications you take are affected by cimetidine and how to manage this interaction.
Cigarette smoking can affect this medication. Tell your doctor if you smoke and if you stop or start smoking while using this medication.
This medication and similar H2 blockers (such as famotidine, nizatidine, ranitidine) are available both with and without a prescription. Do not take them at the same time.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include mental/mood changes, trouble speaking, difficulty awakening.
Do not share this medication with others.
Lifestyle changes such as stress reduction programs, stopping smoking, limiting alcohol, and diet changes (such as avoiding caffeine and spicy foods) may increase the effectiveness of this medication. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.
Lab and/or medical tests may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Information last revised May 2023.
Copyright(c) 2023 First Databank, Inc.
Selected from NATIONAL DRUG DATA FILE (NDDF) data included with permission and copyrighted by First Databank, Inc., 2019. This copyrighted material has been downloaded from a licensed data provider.
The above information is intended to supplement, not substitute for, the expertise and judgment of your health care professional. You should consult your health care professional before taking any drug, changing your diet, or commencing or discontinuing any course of treatment.