Generic name: benznidazole [ benz-NID-a-zole ]
Drug class: Miscellaneous antibiotics

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 23, 2023.

What is benznidazole?

Benznidazole is an antibiotic that is used to treat Chagas disease in children ages 2 through 12 years.

Chagas disease (also called American trypanosomiasis) is an infection caused by a parasite common to the areas of South America, Central America and Mexico.

Benznidazole was approved by the US Food and Drug Administration (FDA) on an "accelerated" basis. In clinical studies, some people responded to benznidazole, but further studies are needed.

Warnings

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use benznidazole if you are allergic to it, or if:

• you are allergic to similar antibiotics such as metronidazole, secnidazole, or tinidazole; or

• you have taken disulfiram (Antabuse) within the past 2 weeks.

You may need to have a negative pregnancy test before starting this treatment.

Benznidazole may harm an unborn baby. Use effective birth control to prevent pregnancy, and tell your doctor if you become pregnant.

Benznidazole may affect fertility (ability to have children) in men. It is not known whether this effect would be permanent.

You should not breastfeed while using benznidazole.

Benznidazole should not be given to a child younger than 2 years old.

How should I take benznidazole?

Take benznidazole exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You may take benznidazole with or without food.

You may need to break a tablet to get the correct dose. For a young child who cannot swallow a tablet whole, you may dissolve the tablet in water to create a liquid for the child to drink.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

Benznidazole doses are based on weight in children. Your child's dose needs may change if the child gains or loses weight.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication.

Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.

Dosing information

Usual Adult Dose for Trypanosomiasis:

US CDC Recommendations: 5 to 7 mg/kg/day orally in 2 divided doses for 60 days

Comments:
-Up to 50 years with chronic Trypanosoma cruzi infection without advanced Chagas cardiomyopathy: Treatment is strongly recommended.
-Older than 50 years with chronic T cruzi infection: Decision to treat with antiparasitic drugs should be individualized, weighing benefits/risks for each patient; factors such as patient age, clinical status, preference, and overall health should be considered.
-Current guidelines should be consulted for additional information.

Usual Pediatric Dose for Trypanosomiasis:

2 to 12 years: 5 to 8 mg/kg/day orally in 2 divided doses

As calculated for tablets:
Less than 15 kg: 50 mg orally twice a day
15 to less than 20 kg: 62.5 mg orally twice a day
20 to less than 30 kg: 75 mg orally twice a day
30 to less than 40 kg: 100 mg orally twice a day
40 to less than 60 kg: 150 mg orally twice a day
60 kg or more: 200 mg orally twice a day

Duration of therapy: 60 days

Comments:
-Doses should be separated by about 12 hours.

Use: For the treatment of Chagas disease (American trypanosomiasis) due to T cruzi
-Approved under accelerated approval based on number of treated patients who became immunoglobulin G (IgG) antibody negative against recombinant antigens of T cruzi; continued approval may depend on verification and description of clinical benefit in confirmatory trials.

US CDC Recommendations:
Less than 12 years: 5 to 7.5 mg/kg/day orally in 2 divided doses
12 years or older: 5 to 7 mg/kg/day orally in 2 divided doses
Duration of therapy: 60 days

Comments:
-Antiparasitic therapy is recommended for all cases of acute/reactivated Chagas disease and for chronic T cruzi infection in children up to 18 years; congenital infections are considered acute disease.
-Current guidelines should be consulted for additional information.

Related/similar drugs

pentamidine, nifurtimox, benznidazole, fexinidazole

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Benznidazole side effects

Get emergency medical help if you have signs of an allergic reaction to benznidazole (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes.

Stop using benznidazole and call your doctor at once if you have:

• numbness, tingling, or burning pain in your hands or feet (may continue for several months); or

• low blood cell counts - fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath.

Common benznidazole side effects may include:

• low white blood cell counts;

• rash or itching;

• stomach pain, nausea, vomiting, loss of appetite;

• headache; or

• weight loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect benznidazole?

Other drugs may affect benznidazole, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use benznidazole only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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