Nitazoxanide (Oral)

Nitazoxanide treats persistent diarrhea which has been caused by parasitic infection, and is often prescribed to patients who have had diarrhea for seven days or more.


Nitazoxanide is an antiprotozoal agent which works to treat diarrhea caused by protozoa Cryptosporidium or Giardia. Protozoa are microscopic, single-celled organisms, and can cause infection in the human body in a similar nature to bacteria. When diarrhea occurs for longer than seven consecutive days, these organisms are assumed to be the cause of the illness. Nitazoxanide inhibits the growth of the protozoa, which leads to relief of diarrhea.

Available only with a doctor's prescription, nitazoxanide is taken orally for a short period of time. In the US, it is known by the brand name Alinia, and the medicine is available in tablet and suspension (liquid) dosage forms. It is suitable for both adults and children over the age of one.

Conditions Treated?

  • Diarrhea caused by Cryptosporidium or Giardia

Type Of Medicine?

  • Antiprotozoal agent

Side Effects

Along with its needed effects, sometimes nitazoxanide can cause unwanted side effects. Although it is unlikely that all side effects will occur, it is important to be prepared for them and recognize the appropriate time to seek medical attention if they are concerning you.

In very rare instances, nitazoxanide can cause diarrhea to worsen or to continue. If your symptoms do not improve while taking the medicine, check with your doctor. The diarrhea may be caused by something other than protozoa and you could require additional treatment. Furthermore, if diarrhea continues it can cause dehydration and electrolyte imbalances, both of which can be extremely dangerous.

The following side effects are less serious and do not usually need to be reported to a doctor unless they become very severe or persistent. Sometimes they dissipate as the body adjusts to the medicine. If you have concerns or questions about them, speak to your doctor.

  • Less common:

O Headache

O Nausea

O Abdominal or stomach pain

O Urine changes

  • Incidence unknown:

O Heartburn

O Vomiting

O Dizziness

O Trouble breathing

O Redness of the skin

O Hives, welts, itching, or skin rash

This may not be an exhaustive list of all side effects that could occur with nitazoxanide therapy. If you notice any other side effects not listed here, consult your doctor as soon as possible. You could also report them to the FDA, or your doctor may do this on your behalf.


The amount of nitazoxanide you take may vary depending on factors personal to you and your medical history. The following are guidelines only, and you should always follow your doctor's dosage instructions.

Oral suspension:

  • Adults and children over 12 years:

O 25 ml taken every 12 hours with food

O Take for 3 days

  • Children aged between 4 and 11 years:

O 10 ml taken every 12 hours with food

O Take for 3 days

  • Children aged between 1 and 3 years:

O 5 ml taken every 12 hours with food

O Take for 3 days

  • Children under 1 year:

O Use and dose determined by doctor


  • Adults and children over 12 years:

O 500 mg taken every 12 hours with food

O Take for three days

  • Children aged up to 11 years:

O Use of tablets not recommended

It is very important to note that the two dosage forms, oral suspension and tablets, contain different amounts of nitazoxanide. You should only ever use the dosage form prescribed to you.

How to use nitazoxanide

Nitazoxanide should always be taken with food, as this helps to reduce stomach discomfort.

If prescribed nitazoxanide tablets, swallow them whole, with water, without chewing, crushing or breaking them.

If prescribed nitazoxanide solution, first shake the medicine thoroughly to ensure it is evenly mixed. Then, measure out the prescribed dosage carefully. You should use a marked measuring spoon or syringe to do this, as a household teaspoon may not hold the correct amount of solution. A measuring device may be provided with the solution, or you could ask your pharmacist for one.

It is very important that you take nitazoxanide consistently every 12 hours. The drug is most effective when a constant amount of it is in the blood, so it is vital that you do not miss a dose. If you do realize you've missed one, take it as soon as you remember unless it is almost time for your next one. In this case, you can skip the missed dose and continue with your original dosing schedule. Do not double doses of nitazoxanide, as doing so could increase the risk of side effects.

Do not stop taking nitazoxanide before the full course has been taken, even if you feel well. Doing so could cause the protozoa to grow back and result in diarrhea returning. Only stop taking the medicine earlier if your doctor instructs you to do so.


You should ensure that your doctor knows about all the medicines you take. This includes those prescribed to you, those purchased over the counter, and any vitamins or herbal supplements you take. Nitazoxanide can interact with other medicines and cause harmful effects. If the drug does interact with the medicines you currently take, your doctor may administer smaller doses, change the times at which you take the medicines, or prescribe alternative medicines where possible.

It is particularly important to tell your doctor if you are taking anticoagulant medicines ('blood-thinners') such as warfarin. You may need to have your blood work monitored throughout treatment with nitazoxanide to check for harmful effects.


Risk to weakened immune system

People with weakened immune systems, for example those with HIV or AIDS, may not be able to take nitazoxanide. It is not known how the drug will affect these conditions, and there is a risk of harmful effects. Your doctor should discuss the risks with you and may want to monitor you more closely throughout your treatment with nitazoxanide if they decide to prescribe it.

Your doctor should also know if you suffer from liver or kidney disease, as these conditions could cause the drug to remain in the body for longer which may increase the risk of side effects.

Pediatric use

Nitazoxanide is just as safe and effective for children aged one year and older as it is for adults. However, smaller doses should be administered to children, and they should only take the oral suspension form of the drug. The safety and efficacy of nitazoxanide in children under one is yet to be established, but doctors may prescribe it if they deem it an appropriate treatment.

Geriatric use

It appears that nitazoxanide is just as safe and effective for elderly patients as it is for younger adults. However, elderly people are more likely to have age-related kidney or liver problems, which means that doctors tend to be more cautious when prescribing the drug to this population. The doctor may request tests to determine kidney and liver function before use of nitazoxanide, or they may monitor the patient more closely throughout treatment.

Pregnancy and breastfeeding

The FDA marks nitazoxanide as a pregnancy category B drug. Animal studies have shown no detrimental effects to the fetus, but there have not been adequate studies in humans to determine evidence of potential fetal harm. The drug can, therefore, be used if benefits of the drug outweigh potential risks to the fetus. If you learn that you are pregnant while taking nitazoxanide, tell your doctor.

It is not known if nitazoxanide is excreted in human breast milk or what harm it may pose to nursing infants if it is. The manufacturer of nitazoxanide, therefore, advises caution when considering the prescription of the drug to nursing women. It may be safer to avoid breastfeeding while taking the drug.


Tell your doctor about all the allergies you suffer from, including food, pollen, dye, chemical and drug allergies, so that they can check you are not allergic to any of the ingredients in nitazoxanide. It is also very important to tell them if you have had a sensitive reaction to nitazoxanide in the past, or to medicines like it.

If you notice any of the following signs of an allergic reaction while taking nitazoxanide, report them to your doctor immediately:

  • Skin rash, hives, or itching
  • Swelling of eyelids, face, lips, tongue, or throat
  • Wheezing, hoarseness, or difficulty breathing


Store nitazoxanide in the container it is provided in with the lid tightly closed at all times when not in use. Keep it in a room temperature environment, away from direct light, heat, or moisture, and do not allow it to freeze. Make sure it is always out of sight and reach of children.

If you have leftover nitazoxanide, do not keep it. Ask your healthcare how to safely dispose of it. They may offer a medicine take-back program. Do not flush nitazoxanide down the toilet or throw it in the trash, as doing so could cause harm to other people or to the environment.


Nitazoxanide is an antiprotozoal agent used to treat diarrhea caused by protozoa Cryptosporidium or Giardia. When diarrhea lasts for longer than 7 days without another known cause, it is usually assumed that protozoa infection is to blame. The medicine works by inhibiting the growth of the protozoa and is most effective when taken every 12 hours for three days.

Designed to be administered orally, nitazoxanide is available in tablet and suspension forms. It is vital that patients only take the dosage form prescribed to them, as the amount of medicine contained in each dosage form is different. Both adults and children over the age of one can take nitazoxanide oral suspension, but the tablets are only suitable for adults and children over 12 years.

Nitazoxanide may cause heartburn, headache, nausea, and mild abdominal pain. Provided that these effects do not become severe or prolonged, there is no need to report them to a doctor. If diarrhea worsens during treatment or does not clear up within three days, patients should consult their doctor. Severe, prolonged diarrhea can be dangerous, so it is important to keep your doctor updated about your condition.