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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Generic drug name: cimetidine (sye MET i deen)
Brand name(s): TAGAMET, TAGAMET HB
GENERIC: available FAMILY: Histamine 2-Blockers
Find the drug label by searching at DailyMed.

Generic drug name: famotidine (fam OAT i deen)
Brand name(s): PEPCID
GENERIC: available FAMILY: Histamine 2-Blockers
Find the drug label by searching at DailyMed.

Generic drug name: nizatidine (nye ZAT i deen)
Brand name(s): AXID, AXID AR
GENERIC: available FAMILY: Histamine 2-Blockers
Find the drug label by searching at DailyMed.

Generic drug name: ranitidine (ra NIT i deen)
Brand name(s): ZANTAC
GENERIC: available FAMILY: Histamine 2-Blockers
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

There were sporadic abortions in an animal study with famotidine. There was no evidence of toxicity in animal studies with ranitidine; no data were available for cimetidine and nizatidine. Use during pregnancy only for clear medical reasons. Tell your doctor if you are pregnant or thinking of becoming pregnant before you take this drug.

Breast-Feeding Warning

These drugs are excreted in human milk. Because of the potential for adverse effects in nursing infants, you should not take these drugs while nursing.

Safety Warnings For This Drug [top]

Nighttime Heartburn Treatments: Try These First

There are nondrug treatments, with no safety concerns, and less expensive drugs that may be effective for you; these should be tried before you use any drugs for heartburn. First, try to avoid foods that trigger your condition (e.g., fatty foods, onions, caffeine, peppermint, and chocolate), and avoid alcohol, smoking, and tight clothing.[1] Second, avoid food, and particularly alcohol, within two or three hours of bedtime. Third, elevate the head of the bed about six inches or sleep with extra pillows.

For both heartburn and ulcers, it is important to avoid drug-induced causes. Aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) are known to cause ulcers. Ask your doctor if acetaminophen could be substituted for these drugs. Check with your doctor about the osteoporosis medications alendronate (FOSAMAX) and risedronate (ACTONEL), which irritate the esophagus.

If these measures are not effective, try simple over-the-counter (OTC) antacids such as a generic aluminum hydroxide and magnesium hydroxide product (MAALOX, MAALOX TC). If symptoms worsen or bleeding occurs, call your doctor. If this does not relieve your symptoms, one of the family of stomach acid–blocking drugs known as histamine2-blockers can be tried. This family includes cimetidine (TAGAMET), famotidine (PEPCID), nizatidine (AXID), and ranitidine (ZANTAC). Histamine2-blockers are available in both OTC and prescription strengths.

If the OTC histamine2-blockers do not give adequate relief of your symptoms after 14 days, it is time to consult your physician.

Facts About This Drug [top]

Cimetidine, famotidine, nizatidine, and ranitidine block the release of stomach acid and are used to treat ulcers and conditions caused by excess stomach acid. They do so by blocking the action of histamine at the histamine2-receptors in certain stomach cells that produce stomach acid. (These drugs are distinct from those that block histamine1—the drugs used for allergy). You should not take these drugs for minor digestive complaints such as occasional upset stomach, nausea, or heartburn, as...

Cimetidine, famotidine, nizatidine, and ranitidine block the release of stomach acid and are used to treat ulcers and conditions caused by excess stomach acid. They do so by blocking the action of histamine at the histamine2-receptors in certain stomach cells that produce stomach acid. (These drugs are distinct from those that block histamine1—the drugs used for allergy). You should not take these drugs for minor digestive complaints such as occasional upset stomach, nausea, or heartburn, as there is no evidence that they are effective for treating those problems.

There is no valid scientific evidence that one of these histamine2-blockers is better than another. All of the histamine2-blockers are now available in nonprescription strengths.

Ulcers often come back after a few months. For frequent, severe recurrences, maintenance therapy using histamine2-blockers is used. If your ulcer disease is resistant to treatment with histamine2-blockers, talk to your doctor about the antibiotic combination treatments that are used to eradicate the bacterium Helicobacter pylori (see Combination Treatments for Helicobacter Pylori Infection). This bacterium is present in a large number of people with ulcers. The presence of this bacterium can be diagnosed with a blood, breath or stool test in people with a history of ulcer disease.

A possible adverse effect with these drugs is confusion.[2] Elderly people are more likely to have reduced kidney or liver function, and are thus at greater risk for this complication. If you have reduced kidney function, your doctor should start you on a low or less frequent dose.

If you are over 60, you should generally be taking less than the usual adult dose of these drugs, especially if you have reduced kidney or liver function. Elderly people eliminate these drugs more slowly than younger people.[3] This means that the drug stays in the body for a longer time, which puts you at a higher risk of adverse effects, particularly dizziness and confusion.[4]

In patients such as the elderly, the immunocompromised, or persons with chronic lung disease or diabetes, there may be an increased risk of developing community-acquired pneumonia. A large epidemiological study showed an increased risk of developing pneumonia in current users of drugs such as these (which suppress gastric acid secretion) compared with patients who had stopped treatment.[5] However, a causal relationship between the use of histamine 2-blockers and pneumonia has not been established.[6] Another study found that there was also a significantly increased risk of pneumonia in healthy children using gastric acid-suppressing drugs such as these. In both studies, the risk applied both to the older H-2 receptor antagonists such as cimetidine, ranitidine, etc., and to the newer proton pump inhibitors (PPI’s) such as omeprazole (PRILOSEC) or lansoprazole (PREVACID). It is likely that the risk also applies to newer drugs such as esomeprazole (NEXIUM).[7]

Rarely, people taking cimetidine have developed bone marrow depression, a serious adverse effect in which the bone marrow is unable to produce blood cells normally. Cimetidine has been shown to cause benign tumors in the testicles of rats,[3] and it can reduce the sperm count in men (and therefore their ability to father children) if it is taken regularly for at least nine weeks.[8] Famotidine, nizatidine and ranitidine are less likely than cimetidine to cause enlarged breasts, decreased sexual ability, and low sex drive.[9]

Cigarette smoking can delay the healing of ulcers.[10] Liquid antacids of aluminum and magnesium in low doses are as effective at healing ulcers as histamine2-blockers and are less costly. However, long-term use of antacids has risks. Antacids with aluminum can cause constipation and those with magnesium can cause severe diarrhea. Those antacids should not be taken by anyone with severe kidney disease. If ulcer symptoms worsen or bleeding occurs, you should seek medical help.

In 2019, the Food and Drug Administration (FDA) announced that some ranitidine products, had been found to be contaminated with N-nitrosodimethylamine (NDMA), a probable human carcinogen (a substance that could cause cancer).[11] Months after several ranitidine manufacturers had halted their worldwide distribution of the drug, the FDA finally requested its removal from the U.S. market on April 1, 2020, after the agency determined that NDMA in some ranitidine products increase over time and when stored at high temperatures.[12]

Before You Use This Drug [top]

Tell your doctor if you have or have had:

  •   allergies to any drugs in this class
  •   immune system problems
  •   kidney or liver problems
  •   phenylketonuria (chewable tablet and oral disintegrating tablet of Pepcid; effervescent, granule, and tablet forms of Zantac)
  •   pregnancy or are breast-feeding

Tell your doctor about any other drugs you take,  including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Call your doctor immediately if you have black, tarry stools or if you vomit material that looks like coffee grounds. These are signs of a bleeding ulcer.
  • Call your doctor if you have trouble swallowing or persistent abdominal pain.
  • Check with your doctor if your symptoms do not improve or get worse.
  • If you take an antacid, take it at least 30 minutes apart from cimetidine. One source suggests taking stomach acid blockers two hours before antacids.[13]
  • Do not drink alcohol or smoke.
  • Avoid any food or drink that aggravates your ulcer.
  • Check with your doctor before taking any aspirin, ibuprofen, or other NSAIDs. These drugs can cause or aggravate ulcers.
  • Avoid exposure to organophosphate pesticides, such as Diazinon.[14]

 

How to Use This Drug [top]

  • If you miss a dose, take it as soon as you remember, but skip it if it is almost time for the next dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Take this drug for the prescribed length of time. If you stop too soon, your symptoms could come back.
  • Nonprescription strengths: Do not take maximum daily dose for more than two weeks unless your doctor tells you to do so.
  • Prescription strengths: If 1 dose per day, take at bedtime. If 2 doses per day, take in the morning and at bedtime. If several doses per day, take with meals and at bedtime.
  • Famotidine chewable tablets: Chew well before swallowing.
  • Famotidine oral disintegrating tablets: Open pack just before use and place tablet on tongue to dissolve and swallow.
  • Ranitidine effervescent granules or tablets: Dissolve in six to eight ounces of water and drink.
  • Cimetidine tablets have an odor. This is normal and no cause for concern.
  • Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Do not let the liquid form freeze. Keep out of reach of children.

 

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

ADALAT, ADALAT CC, AGENERASE, alprazolam, altretamine, amitryptiline, amprenavir, ANECTINE, ANZEMET, AVENTYL, AVINZA, BICNU, carbamazepine, carmustine, chlordiazepoxide, clozapine, CLOZARIL, COGNEX, COUMADIN, delavirdine, desipramine, DIASTAT, diazepam, DILANTIN, dofetilide, dolasetron, DURAQUIN, ELAVIL, ELIXOPHYLLIN, FAZACLO, FLAGYL, flecainide, FLOMAX, GLIADEL, glipizide, GLUCOPHAGE, GLUCOTROL, GLYCET, HALCION, HEXALEN, imipramine, INDERAL, INDERAL LA, KADIAN, ketoconazole, labetalol, lercanidipine, LIBRIUM, lidocaine, MALARONE, METAGLIP, metformin, metronidazole, midazolam, miglitol, MIRAPEX, mizolastine, morphine, MS CONTIN, nifedipine, NIZORAL, NORMODYNE, NORPRAMIN, nortryptiline, ORAMORPH, PAMELOR, PERTOFRANE, phenytoin, pramipexole, procainamide, PROCANBID, PROCARDIA, PROCARDIA XL, proguanil, PRONESTYL, propranolol, QUINAGLUTE DURA-TABS, QUINIDEX, quinidine, RESCRIPTOR, ROXANOL, sertraline, sildenafil, SLO-BID, succinylcholine, tacrine, TAMBOCOR, tamsulosin, TEGRETOL, THEO-24, theophylline, TIKOSYN, TOFRANIL, TRANDATE, triazolam, VALIUM, VERSED, VIAGRA, warfarin, XANAX, XYLOCAINE, ZOLOFT, ZOMIG, zolmitriptan.

Adverse Effects [top]

Call your doctor immediately if you experience (for all histamine2-blockers):

  •   allergic reaction or hives
  •   bleeding or bruising that is unusual
  •   blisters on palms and soles of feet
  •   confusion or anxiety
  •   dizziness or fainting
  •   eyes that are red or irritated
  •   fever, chills, or sore throat
  •   general feeling of discomfort
  •   hallucinations
  •   heartbeat fast, pounding, or irregular
  •   joint pain
  •   mood or mental changes
  •   muscle cramps
  •   peeling skin
  •   skin that is red or itching
  •   tiredness or weakness that is unusual
  •   trouble breathing
  •   ulcers or white spots on lips, in mouth, or on genitals
  •   urination increased or decreased[15]
  •   yellow skin or eyes

<> For cimetidine:

 

  •   abdominal pain
  •   fever or sore throat
  •   joint pain
  •   muscle ache
  •   tiredness or weakness that is unusual
  •   vomiting

For famotidine:

  •   fever or sore throat
  •   heartbeat fast, pounding, or irregular
  •    joint pain
  •    muscle ache
  •    tiredness or weakness that is unusual
  •   wheezing or troubled breathing

For nizatidine:

  •   chest and back pain
  •   increased cough
  •   itching or hives
  •   joint pain
  •   skin rash
  •   tiredness or weakness that is unusual
  •   upper respiratory infections more frequent
  •   vision changes
  •   wheezing or troubled breathing

For ranitidine:

  •   abdominal pain
  •   chest and back pain
  •   faintness or weakness that is sudden
  •   fever
  •   heartbeat irregular or fast
  •   joint pain
  •   muscle ache
  •   throat sore
  •   tiredness or weakness that is unusual
  •   vision changes
  •   vomiting
  •   wheezing or troubled breathing

Call your doctor if these symptoms continue (for all histamine2-blockers):

  •   breasts enlarged or sore in males or females
  •   diarrhea
  •   dizziness
  •   drowsiness
  •   headache
  •   impotence
  •   muscle cramps or pain
  •   sexual desire decreased
  •   skin rash

For cimetidine:

  •   fever
  •   hair loss
  •   joint pain
  •   muscle tenderness
  •   skin rash or hives
  •   urination difficult
  •   urination increased or decreased

For famotidine:

  •   abdominal pain
  •  
  •   constipation
  •   ears ringing
  •   hair loss
  •   mouth dry
  •   nausea
  •   skin dry
  •   sleeping difficulty
  •   vomiting

For nizatidine:

  •   abdominal pain
  •   constipation
  •   mouth dry
  •   nausea or vomiting
  •   nose running
  •   sleeping difficulty
  •   sweating increased

For ranitidine:

  •   abdominal pain
  •   constipation
  •   hair loss<
  •   nausea or vomiting
  •   sleeping difficulty

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  •   Vitamin B12 measurements

last reviewed March 31, 2021