Nizatidine belongs to the family of medications called H2-receptor antagonists. Nizatidine works by reducing the amount of acid secreted by the stomach. Reducing the acid helps to reduce the pain of stomach and intestinal ulcers and heartburn and assists in the healing of ulcers and damage caused by gastroesophageal reflux disease. Nizatidine is also used to prevent duodenal (intestinal) ulcers in certain circumstances.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The adult dose of nizatidine ranges depending on the condition being treated. For the treatment of stomach and intestinal ulcers, the usual dose is 300 mg daily (either 150 mg twice a day or 300 mg at bedtime). Ulcers usually heal within 4 weeks, but 8 weeks of treatment may be necessary.

To prevent the return of ulcers that have been healed, the usual dose is 150 mg daily at bedtime, for a period of 6 to 12 months, depending on the severity of the initial ulcer. 

For gastroesophageal reflux disease, the usual dose is 150 mg twice a day.

Nizatidine may be taken with or without food, and swallowed with a full glass of water. Antacids may be used along with nizatidine if extra relief from excess acid is needed.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication regularly and exactly as prescribed by your doctor. Do not stop taking this medication without first talking with your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to nizatidine or to any of the ingredients of the medication
• are allergic to any H2-receptor antagonists (e.g., ranitidine, famotidine, cimetidine)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• back pain
• body pain
• constipation
• diarrhea
• dizziness
• drowsiness
• dry mouth
• feeling anxious or nervous
• flaky or peeling skin
• flu- or cold-like symptoms (e.g., sore throat, cough, runny or stuffy nose)
• headache
• heartburn
• increased gas
• increased sweating
• itching
• muscle or joint pain
• nausea
• sleepiness
• stomach pain
• trouble sleeping
• unexplained muscle weakness or tenderness
• vomiting
• weakness or tiredness
• weight loss

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• chest pain
• confusion
• fever
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• signs of gout (e.g., joint pain, swelling and warmth of joints)
• signs of infection (increased frequency of symptoms, may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• skin rash or hives
• symptoms of liver problems (e.g., abdominal pain, fatigue, flu-like symptoms, light coloured stools, nausea, vomiting, yellowing of the skin or eyes)
• unusual tiredness or shortness of breath when exercising

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of an allergic reaction:
• swelling of the hands, feet, ankles, face, lips, mouth, or throat
• difficulty breathing or swallowing

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin taking a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Kidney function: Nizatidine is removed from the body by the kidneys. If you have reduced kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Nizatidine is partly broken down by the liver. If you have reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Severe stomach problems: If you have recurrent vomiting, difficulty swallowing, blood in the stool, significant unintentional weight loss, fatigue (anemia), or are coughing up blood, check with your doctor right away.

Vitamin B12: Long-term use of nizatidine may lead to vitamin B12 deficiency. If you are a vegetarian or have low vitamin B12 levels, discuss with your doctor whether any special monitoring is required.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking nizatidine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

There may be an interaction between nizatidine and any of the following:

• acalabrutinib
• acetylsalicylic acid (ASA)
• "azole" antifungals (e.g., itraconazole, ketoconazole, posaconazole, voriconazole)
• bosutinib
• cefuroxime
• cyclosporine
• cysteamine
• dasatinib
• erlotinib
• gefitinib
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• ledipasvir
• multivitamin/mineral supplements
• nilotinib
• octreotide
• pazopanib
• rilpivirine
• risedronate
• varenicline
• velpatasvir

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.