Cimetidine

Uses

What is cimetidine used for?

Cimetidine belongs to a group of medications called histamine type-2-receptor antagonists that block the release of histamine which triggers the secretion of stomach acid.

By blocking H-₂ receptors, it prevents the secretion of gastric acid into the stomach. H-₂ blockers do not bind to H-₁ receptors, so they do not produce the same effects as antihistamines.

Cimetidine is used to treat the following:

• Benign gastric and duodenal ulceration
• Gastroesophageal reflux disease (GERD)
• Heartburn
• Zollinger-Ellison syndrome
• Stress ulcers
• Prevention of acid aspiration during general anesthesia
• Dyspepsia (indigestion)
• Short bowel syndrome
• Pancreatic insufficiency

How should I take cimetidine?

Cimetidine is available as an oral tablet and intravenous (IV) solution. The oral tablet should be taken by mouth and swallowed whole without chewing or crushing it. It should be taken before meals.

The IV solution should be administered by a licensed health professional.

How do I store cimetidine?

This drug should be stored at room temperature (<30°C) and be protected from light and moisture. Do not freeze this product. Always check the label before using this product. For safety, keep out of the reach of children and pets.

Do not use if the printed expiration date has passed, the product seal has been broken, or the product has changed in color, odor, or consistency.

Do not dispose of this product by pouring it down the drain, toilet, or into the environment. Ask your pharmacist regarding the proper way and location of disposal.

Precautions & Warnings

What should I know before using cimetidine?

Before using this medication, inform your doctor if:

• You have ever had an allergic reaction to cimetidine.
• You have a history of allergy to other medications, food, or other substances.
• You are taking other medications.
• You have underlying health conditions.

Is it safe during pregnancy or breastfeeding?

Cimetidine is a pregnancy category B drug. There are no adequate and well-controlled studies using cimetidine in pregnant women, however, animal studies have not shown any risk to the fetus. This drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, as determined by your doctor.

This drug may be excreted in breast milk. This drug should be used while breastfeeding only if the potential benefit justifies the potential risk to the child, as determined by your doctor.

Side Effects

What side effects can occur when using cimetidine?

All drugs have the potential to elicit side effects even with normal use. Many side effects are dose-related and will resolve when it is adjusted or at the end of therapy.

Potential side effects while using this drug include:

• Diarrhea
• Gastrointestinal disturbances
• Dizziness
• Headache
• Tiredness
• Muscle and joint pain
• Rashes
• Altered liver function tests
• Confusion

Rare adverse reactions:

• Hypersensitivity reactions
• Fever
• Hair loss (alopecia)
• Blood disorders
• Acute pancreatitis
• Interstitial nephritis
• Hallucinations
• Depression
• Cardiovascular disorders
• Transient hypotension
• Gynecomastia
• Impotence

Potentially fatal reactions:

• Hepatotoxicity
• Cardiac arrest
• Arrhythmias

You may experience some, none, or other side effects not mentioned above. If you experience serious adverse reactions, you must stop taking the drug immediately. If you have any concerns about a side effect or it becomes bothersome, consult your doctor or pharmacist.

Interactions

What drugs may interact with cimetidine?

This drug may interact with other medications. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist.

Known drugs and their interactions with medication include:

• Dasatinib
  • Reduced absorption of these drugs
• Ketoconazole, itraconazole, posaconazole
  • Reduced absorption of these drugs
• Phenytoin
  • Increased serum levels of this drug
• Theophylline
  • Increased serum levels of this drug
• Lidocaine
  • Increased serum levels of this drug
• Hydroxyzine
  • Increased serum levels of this drug
• Oral anticoagulants
  • Increased serum levels of this drug
• Antacids
  • Absorption of cimetidine may be reduced

If you experience an adverse drug interaction, stop taking this drug and continue taking your other medication. Inform your doctor immediately to reevaluate your treatment plan. Your dose may need to be adjusted, substituted with another drug, or discontinue using the drug.

Does food or alcohol interact with cimetidine?

Food may reduce the rate and amount of absorption of cimetidine. Do not take cimetidine with alcohol as it may cause gastric irritation.

Inform your doctor or pharmacist if you have any concerns regarding food-drug interactions.

What health conditions may interact with cimetidine?

This drug should be taken with caution if you have any of the following conditions or risk factors:

• History of peptic ulcers
• Diabetes mellitus

Inform your doctor or pharmacist if you have any concerns regarding specific health conditions.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult your doctor or pharmacist before using cimetidine.

What is the dose of cimetidine for an adult?

For prophylaxis of gastrointestinal hemorrhage from stress ulcers

• Take 200 to 400 mg every 4 to 6 hours.

For treating benign gastric and duodenal ulceration

• Oral: take 800 mg at bedtime or 400 mg twice a day, increasing to 4 times a day if necessary.
  • 4 weeks for duodenal ulcers
  • 6 weeks for gastric ulcers
  • 8 weeks for NSAID-associated ulcers
• IV:
  • Intermittent infusion: Administer 300 mg every 6 to 8 hours infused over 15 to 20 minutes. Maximum daily dose of 2400 mg.
  • Continuous infusion: Administer 37.5 mg/hour (900 mg/day). A 150 mg IV loading dose may be given in patients requiring rapid elevation of gastric pH.

For treating pancreatic insufficiency

• Take 800 to 1600 mg per day in 4 divided doses, 60-90 minutes before meals.

For treating non-ulcer dyspepsia

• Take up to 800 mg per day in divided doses.

For treating Zollinger-Ellison syndrome

• Oral: take 300 to 400 mg 4 times per day. Increase the dose if necessary.
• IV:
  • Intermittent infusion: Administer 300 mg every 6 to 8 hours infused over 15 to 20 minutes. Maximum daily dose of 2400 mg.
  • Continuous infusion: Administer 37.5 mg/hour (900 mg/day). A 150 mg IV loading dose may be given in patients requiring rapid elevation of gastric pH

For treating GERD

• Take 400 g 4 times a day or 800 mg two times a day for 4 to 12 weeks.

As prophylaxis of acid aspiration during general anesthesia

• Give 400 mg 90 to 120 minutes before the induction of anesthesia or at the start of labor.
• The dose may be increased up to 400 mg every 4 hours, if necessary.
• Maximum daily dose of: 2.4 g

For treating short bowel syndrome

• Give 400 mg two times a day. Adjust the dose according to the response.

What is the dose of cimetidine for a child?

This drug is not recommended for use in children and the recommended dose has not been established. Consult with a doctor or pharmacist for alternatives and more information.

How is cimetidine available?

This drug is available in the following brands, dosage forms, and strengths:

• Cimedine tablet 400 mg
• Cimular solution for injection 100 mg/mL
• Endure Medical cimetidine solution for injection
• Lafayette cimetidine
• RiteMED cimetidine
• Shintamet tablet 400 mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of this drug, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.