Tinidazole (Oral)

Tinidazole is a drug used primarily to treat infections caused by single cell organisms called protozoa, although it is also an antibiotic and is used to treat some bacterial infections.


Tinidazole works by entering the cells of the bacteria or protozoa that are causing the infection, and damaging their DNA. This ultimately kills the organism, which clears up the infection and relieves your symptoms.

The drug is highly effective in treating a wide range of infections such as trichomoniasis and bacterial vaginosis, and will typically clear up the infection within 3 to 5 days. In some cases, a single dose of tinidazole is all that is required to fight the infection. It is not a general purpose or “broad-spectrum” antibiotic, and is only used to treat specific conditions.

As with other drugs in this class, it is important to complete the full course of treatment even if the symptoms go away before you finish the course. This is because infections may still be present even when they do not cause any symptoms. If you do not complete the course they will multiply and the symptoms will return, or they may become resistant to the treatment.

Tinidazole interacts with several medications in ways that can produce undesired side effects. If you are prescribed this drug, make sure your doctor is aware of any medication that you are already taking. You should also discuss your medical history with your doctor, as tinidazole can make certain conditions worse, especially blood diseases, central nervous system (CNS) diseases, epilepsy, liver disease, thrush, or vaginal yeast infection.

Tinidazole also interacts with alcohol, and drinking alcohol at the same time as this medication can cause stomach pain, nausea and vomiting. You should therefore avoid the consumption of alcohol while you are taking tinidazole and for three days after you stop taking it. This includes any over the counter products containing alcohol.

Conditions Treated

  • Protozoan infections
  • Bacterial infections
  • Trichomoniasis
  • Giardiasis
  • Amebiasis
  • Bacterial Vaginosis

Type of Medicine

  • Antiprotozoal

Side Effects

A side effect is an unpleasant or undesirable effect of a drug, that occurs in addition to its intended effects. Tinidazole is a well-tolerated drug and serious side effects are rare. However, they can occur in some people. Seek medical attention if you experience any of the following:

  • Flu symptoms including fever, chills and body aches
  • Numbness, tingly sensations, or burning sensations
  • Seizure, muscle spasms, shaking, or convulsions

Other less serious side effects may occur in some instances. Consult your doctor or pharmacist if you experience any of the following:

  • Decreased appetite
  • Feeling tired or weak
  • Metallic or bitter taste in the mouth
  • Mild dizziness
  • Mild headaches

Tinidazole may also cause minor gastrointestinal problems, such as a mild upset stomach, flatulence, and feelings of nausea. These are more common when the medication is taken on an empty stomach. If you experience this, try taking your medication with food. This should relieve the symptoms, but if it does not, or if you experience other symptoms like diarrhea, stomach pain or vomiting, consult your doctor.

This is not an exhaustive list and you may experience side effects not mentioned here. If you experience anything unusual or bothersome, discuss the matter with your doctor or pharmacist. You may be able to take another drug or product to manage the side effects.

Allergic reactions

Serious allergic reactions to tinidazole are rare, however they can occur. You may also be allergic to the other ingredients in the tablet, such as the filler. If you experience any of the following symptoms call 911 immediately for medical assistance:

  • Difficulty breathing or wheezing
  • Skin problems such as hives, redness, or itching
  • Drowsiness, dizziness, loss of coordination
  • Swelling, especially around the face, throat or tongue


Always take the amount of tinidazole that you have been prescribed to take by your doctor. The dose of tinidazole given can vary from person to person, and your dose will depend on your medical history, your age, and the medical condition that you are trying to treat. In some cases, a single dose of tinidazole will be sufficient to fight the infection and relieve your symptoms. However, you may be advised to take tinidazole for a longer period, for example 3-5 days. The following dosages are common:

Amebic liver abscess

Adults: 2 grams daily, for 3-5 days
Children aged 3+: 50 mg per kg of bodyweight (max 2 grams) daily, for 3-5 days

Bacterial vaginosis

Adults: 2 grams daily for 2 days, or 1 gram daily for 5 days
Children (any age): the suitability and dose of the drug will be determined on a case-by-case basis


Adults: 2 grams as a single dose
Children aged 3+: 50 mg per kg of bodyweight (max 2 grams) as a single dose

Intestinal amebiasis

Adults: 2 grams daily for 3 days
Children aged 3+: 50 mg per kg of bodyweight (max 2 grams) daily, for 3 days


Adults: 2 grams as a single dose
Children (any age): the suitability and dose of the drug will be determined on a case-by-case basis

You may be given your tinidazole in divided doses, to be taken at evenly spaced times throughout the day. This is to make sure there is a consistent amount of the medication in the bloodstream. Likewise, if you are prescribed one dose per day, try to take it at the same time each day. Do your best to stick to your dosing schedule, as this will give you the best chance of fighting the infection.

If you do forget to take a dose, take it as soon as you remember. The exception to this is if it is almost time for you to take the next dose. In this case, you should skip the missed dose. Do not take a double dose of tinidazole to make up for the dose you missed.


Tinidazole may cause undesired side effects when taken at the same time as some other medications. Make sure your doctor is aware of all medications, herbal supplements, vitamins or other products you are taking. The following medications and substances are of particular concern:

Alcohol - you should abstain from alcohol for the entire period that you are taking tinidazole, and for at least three days after you finish your course. If you normally drink a lot of alcohol, or if you think you would find it difficult to stop, tell your doctor. You should also avoid any products or preparations listing alcohol, ethanol or propylene glycol as one of their ingredients, such as some cough medication. Possible side effects include:

  • Abdominal cramps
  • Flushing of the skin
  • Headaches
  • Nausea and vomiting
  • Stomach pain

Cholestyramine - this drug interferes with the absorption of tinidazole, so you will likely be advised to take the two drugs at different times of day.

CYP3A4 Inducers and Inhibitors - CYP3A4 inducers include fosphenytoin, phenobarbital, phenytoin, rifampin, and may decrease the effect of your tinidazole medication. CYP3A4 inhibitors include cimetidine and ketoconazole, these drugs may increase the effect of tinidazole. Your doctor will likely adjust the dosages of your medication to compensate.

Cyclosporine and tacrolimus - these drugs are used in patients who have received an organ transplant. Although the evidence is limited, there is some reason to believe that tinidazole increases the levels of these drugs in the blood.

Disulfiram - this drug is usually used to treat alcoholism and creates an unpleasant sensitivity to alcohol. Symptoms of psychosis may occur when these two drugs are taken together.

Fluorouracil - tinidazole may increase the side effects that people experience while taking fluorouracil. Your doctor will probably recommend that you do not take these drugs at the same time, however, if that cannot be avoided, you will likely be monitored closely.

Lithium - tinidazole may enhance the effect of lithium. Your doctor may want to adjust your dose of lithium, or you may undergo regular blood tests to avoid lithium poisoning.

Oxytetracycline - this medication may block the effects of tinidazole.

Warfarin - warfarin is an oral coumarin anticoagulant which thins the blood and stops it from clotting. Tinidazole can enhance the effect of warfarin, which can potentially be dangerous. This does not mean the two drugs cannot be taken together, but the dose of warfarin may need to be lowered during the time that you are taking tinidazole, and for up to 8 days afterwards.


As with antibiotics, it is very important that you complete the full course of your treatment with tinidazole, even if your symptoms clear up. You may start feeling better before the infection is fully cleared up, but if you stop taking the medication, the infection and symptoms may come back.

Some evidence of carcinogenicity has been demonstrated in animal studies testing drugs that are similar in nature to tinidazole. This means it is possible that this drug can make cells become cancerous. It should therefore be used only when protozoan infection is strongly suspected or has been proven by the appropriate laboratory tests. If you already have cancer or are at risk of developing it, your doctor will advise you on the risks and benefits of taking this medicine.

Tinidazole can interact with certain medical conditions in negative ways. You should discuss your medical history with your doctor, and tell them about any medical conditions that you currently suffer from. Your doctor may still prescribe tinidazole to you, but they may need to prescribe a different dose or they may want you to come in for more frequent check ups. They can also make you aware of what the side effects might be. The conditions listed below are of particular concern:

  • Blood disease - tinidazole may make blood diseases or blood cell disorders worse. You should also tell your doctor if you have previously suffered from blood disease.
  • Central nervous system (CNS) disease or epilepsy - you may experience more frequent seizures or convulsions while taking tinidazole.
  • Liver disease - tinidazole can sometimes cause side effects to the liver, and so should be taken with caution by people with liver disease.
  • Thrush or vaginal yeast infection - tinidazole may make this condition worse.

Pregnant women should not take tinidazole during the first trimester of their pregnancy, as this may be harmful to the baby. For this reason you should use birth control while you are taking the medication. Beyond the first trimester, the risks and benefits of taking the drug must be balanced. Your doctor will advise you on this and help you come to an appropriate decision.

Tinidazole can pass into the breast milk, and therefore women are recommended to stop breastfeeding during the course of the treatment, and for an additional three days afterwards as the drug can remain in the body for some time, even after you have stopped taking it.

If you are taking tinidazole to treat a sexually transmitted infection, your doctor may advise that your partner receive treatment too.

The safety of tinidazole when taken by children under the age of 3 years old has not been established and there may be some risks involved. Your doctor will explain the alternative options available to you.

Tinidazole is considered safe to use by older individuals. However, older patients are more likely to also suffer from other conditions, such as kidney or liver problems, that may lead to a different dose being prescribed than a younger patient may receive.


If you do not store your medication properly, their potency may be reduced or they may become unsafe to take. Follow these guidelines to store your medicine safely:

Store at room temperature - If your medication becomes too hot or too cold, it may become damaged. You should therefore store your medication at room temperature. Keep the medicine away from sources of heat such as the oven, heaters, and radiators. Your bathroom, and the glove compartment of your car, are also usually too warm to store medication. Also, do not keep your medication in the refrigerator or the freezer, as this can also cause damage.

Store in a dry location - Moisture can damage your medication, so store your tablets in a dry place. Although many people store their medications in the medicine cabinet in their bathroom, this is actually a poor location because of the moisture as well as the heat.

Keep away from direct sunlight - Do not store your medication near windows or in other locations where they can be exposed to direct sunlight.

Keep away from children - This medication can be dangerous if consumed by children. Store the tablets in a high location that is out of the reach and sight of children, and keep them in child-safe containers.

If you follow these guidelines, your medication will be safe to use as long as it is also within the expiration date on the packaging. However, you should be aware of signs of damage to the tablets, such as chips, cracks, moisture, softness, crumbling, or tablets sticking together. If you see these signs, the tablets may be damaged and you should not take them.

To dispose of any tablets that are damaged, past their expiration date, or unneeded, consult your pharmacist. They can advise you about any “take-back” schemes operating in your area where you can dispose of your unused medications, or they may be able to take them from you themselves.


Tinidazole is an effective treatment for a wide variety of bacterial and protozoan infections and is a well-tolerated drug which does not cause side effects in the vast majority of people who take it.

However, the risk of side effects are greater if you take certain medications, suffer from certain medical conditions, or if you drink alcohol while taking the drug. It is also not recommended for women in the first trimester of their pregnancy. You should always discuss your medical history and any medications you take with your doctor before you take tinidazole.

Always complete your full course of treatment with tinidazole. If you are given a five day course, but your symptoms clear up in three, take the drug for the final two days anyway. The infection might not be completely removed, and may come back. This may also cause the infection to become resistant to the treatment.

Tinidazole is considered an effective treatment for certain specific conditions, and depending on the specific medical problem you have, your symptoms will typically clear up within 1 to 5 days.

Last Reviewed:
December 24, 2017
Last Updated:
April 05, 2018
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