Cimetidine (
Tagamet®) is a medicine that is available as prescription medication and as an over-the-counter drug. It is used to treat several conditions related to the esophagus, stomach, and intestines. It is part of a class of drugs known as
H2 blockers.
The manufacturer of brand-name cimetidine (Tagamet and Tagamet HB®) is GlaxoSmithKline, although brand-name prescription Tagamet is no longer being made. Several manufacturers make generic versions in prescription and over-the-counter strengths.
Uses of prescription cimetidine include the treatment of:
- Duodenal ulcers (ulcers in the very first part of the intestine after the stomach): It can be used to treat a duodenal ulcer and also to prevent ulcers from coming back.
- Gastric ulcers (stomach ulcers): It is approved to treat benign (non-cancerous) gastric ulcers.
- Gastroesophageal reflux disease (GERD): It helps treat GERD, helping to relieve heartburn and heal esophagitis (damage to the esophagus) due to GERD.
- Pathological hypersecretory conditions: It helps to treat these conditions (in which too much stomach acid is produced), such as Zollinger-Ellison syndrome.
The over-the-counter form of cimetidine is approved for the following conditions:
- Heartburn
- Acid indigestion
- Sour stomach.
This non-prescription form of cimetidine can be used to treat these problems once they have started. Also, it can be used to prevent these problems if taken before eating or drinking foods or beverages that cause heartburn.
Cimetidine is an "
H2 blocker" that works by blocking a specific kind of histamine receptor. Histamine is a chemical released by the body that has several effects. In the stomach, histamine causes more acid to be produced. By blocking histamine in the stomach, cimetidine reduces the amount of acid produced by the stomach. This is why cimetidine is known as an "acid reducer."
There have been several studies looking at how well the medication treats several conditions.
Ulcers
In one study of cimetidine's effectiveness for treating (upper intestinal ulcers), ulcers were healed in up to 86 percent of people who took cimetidine within four weeks of treatment. After eight weeks of treatment, up to 94 percent of people showed ulcer healing. Studies have also shown that it can prevent duodenal ulcers from returning.
In studies looking at using cimetidine for gastric ulcer (stomach ulcer) treatment, up to 76 percent of people taking it experienced stomach ulcer healing within six weeks. Ulcers healed in 55 percent of people who were not taking it.
GERD and Esophagitis
Studies have looked at using cimetidine for
gastroesophageal reflux disease (
GERD). These studies have shown cimetidine was effective for relieving GERD symptoms. These studies also showed that it helped to heal esophagitis (damage to the esophagus) due to GERD. Up to 67 percent of people taking cimetidine showed esophageal healing within 12 weeks, compared to just 36 percent of those not taking it.
Pathological Hypersecretory Conditions
Studies have been conducted to assess the effectiveness of using cimetidine to treat several pathological hypersecretory conditions (in which too much stomach acid is produced), such as Zollinger-Ellison syndrome. These studies showed that cimetidine can decrease stomach acid production and relieve symptoms associated with pathological hypersecretory conditions.
When and How to Take Cimetidine
Some general considerations for when and how to take the medication include the following:
- It comes in tablet form. It is usually taken by mouth one to four times a day, depending on the condition being treated.
- For people with difficulty swallowing capsules or tablets, prescription cimetidine also comes in a solution (liquid) form.
- You may take it with or without food. If you are using over-the-counter cimetidine to prevent heartburn, you should take it right before eating (or up to 30 minutes before eating), up to twice a day.
- If you take it on a regular basis (not just when you need it), you should take it at the same time(s) each day to maintain an even level of the drug in your blood. If you take it just once a day, it is usually best to take it in the evening or before bedtime.
- For the medicine to work properly, it must be taken as prescribed. It will not work if you stop taking it.
The dosage your healthcare provider recommends will vary depending on a number of factors, including:
- The medical condition being treated
- Your age
- Other medical conditions you may have
- Other medications you may be taking.
As with any medication, do not adjust your cimetidine dose unless your healthcare provider specifically instructs you to do so.
As with any medicine, there are possible side effects. However, not everyone who takes the medication will experience side effects. In fact, most people tolerate it well. When side effects do occur, in most cases they are minor and either require no treatment or can easily be treated by you or your healthcare provider. Serious side effects are less common.
The most common side effects of cimetidine include:
(Click Cimetidine Side Effects to learn about specific side effects of the drug, including some of the more serious side effects that you should report to your healthcare provider. You can also read about other possible side effects by going to Cimetidine and Impotence.)
Drug Interactions With Cimetidine
Cimetidine can potentially interact with several medicines.
What Should I Tell My Healthcare Provider?
You should talk with your healthcare provider before taking this medication if you have:
- Kidney problems, such as kidney failure (renal failure)
- Liver problems, such as liver failure or cirrhosis
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you:
Tell your healthcare provider about all the medicines you currently take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Alternatives to Cimetidine
For most people, cimetidine is quite effective at treating
GERD, ulcers, or other digestive problems. It is also generally well-tolerated. However, side effects can occur, or the medicine may not work as well as needed. In these cases, your healthcare provider may recommend an alternative to cimetidine. Some examples of substitute medications include:
Other alternatives to cimetidine include diet changes
(see GERD Diet) and surgery (for more serious problems).
People who take too much cimetidine may have overdose symptoms that could include:
- Trouble breathing
- Rapid heart rate (tachycardia)
- Coma
- Loss of life.
If you happen to overdose, seek medical attention immediately.
It should be stored at room temperature, away from moisture or heat. Cimetidine tablets and oral solution should be kept in an airtight container.
Keep cimetidine and all medications out of the reach of children.
What Should I Do If I Miss a Dose?
Many people take cimetidine only when they need it. However, for those who take it on a daily basis, if you do not take your cimetidine as scheduled, take your next dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not take a double dose of cimetidine.
Generic prescription cimetidine is available in the following strengths:
- Cimetidine 300 mg tablets
- Cimetidine 400 mg tablets
- Cimetidine 800 mg tablets
- Cimetidine solution -- 300 mg per 5 mL (300 mg per teaspoonful).
Prescription
Tagamet is no longer being made.
Over-the-counter cimetidine is available as Tagamet HB 200 mg tablets. Cimetidine is also available in an injectable form for use in hospitals.
Currently, generic prescription cimetidine tablets, cimetidine solution, and over-the-counter cimetidine tablets are licensed for sale.
