Version July 2025
Chagas disease:
Weight-directed dosing: Infants, Children, and Adolescents (limited data available in ages <2 years and >12 years): Oral: 2.5 to 4 mg/kg/dose every 12 hours for 60 days; maximum dose: 200 mg/dose (Ref).
Fixed dosing:
Children 2 to 12 years (Ref):
<15 kg: Oral: 50 mg every 12 hours for 60 days.
15 to <20 kg: Oral: 62.5 mg every 12 hours for 60 days.
20 to <30 kg: Oral: 75 mg every 12 hours for 60 days.
30 to <40 kg: Oral: 100 mg every 12 hours for 60 days.
40 to <60 kg: Oral: 150 mg every 12 hours for 60 days.
≥60 kg: Oral: 200 mg every 12 hours for 60 days.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
(For additional information see "Benznidazole: Drug information")
Chagas disease (T. cruzi infection; American trypanosomiasis) (off label): Oral: 5 to 7 mg/kg/day in 2 divided doses for 60 days (Ref). Alternatively, 5 mg/kg/day in 2 divided doses (maximum dose: 300 mg/day) for 60 days; for patients weighing >60 kg, the total dose expected should be calculated, extending the treatment time beyond 60 days (eg, patients weighing 65 kg receive 300 mg/day for 65 days; patients weighing 70 kg received 300 mg/day for 70 days) (Ref). Note: For patients with HIV, 5 to 8 mg/kg/day (usual maximum: 300 mg/day) in 2 divided doses is recommended for 60 days (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Dermatologic: Skin rash (16%), skin lesion (11%)
Endocrine & metabolic: Weight loss (13%)
Gastrointestinal: Abdominal pain (25%), decreased appetite (5%)
1% to 10%:
Central nervous system: Headache (7%), peripheral neuropathy (2%)
Gastrointestinal: Nausea (5%), vomiting (5%), anorexia (<5%), diarrhea (4%)
Hepatic: Increased serum transaminases (5%)
Neuromuscular & skeletal: Arthralgia (<5%), tremor (2%)
<1%, postmarketing, and/or case reports: Acute generalized exanthematous pustulosis, ageusia, agranulocytosis, amnesia, arthritis, disorientation, dress syndrome, edema, epigastric pain, erythema multiforme, erythematous plaques, erythematous rash, exfoliation of skin, exfoliative dermatitis, eyelid edema, fatigue, fever, granulocytopenia, headache, hepatitis, hypoesthesia, increased serum alkaline phosphatase, increased serum bilirubin, insomnia, lack of concentration, lymphadenopathy, maculopapular rash, musculoskeletal pain, myalgia, paresthesia, pruritic rash, seizure, skin blister, swelling of extremities, thrombocytopenia, toxic epidermal necrolysis, toxic hepatitis, weakness, xerostomia
Hypersensitivity (eg, severe skin and soft tissue reactions) to benznidazole, other nitroimidazole derivatives, or any component of the formulation; use of disulfiram within previous 2 weeks of benznidazole therapy; Cockayne syndrome.
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Concerns related to adverse effects:
• Carcinogenic/genotoxic: Carcinogenicity has been observed in mice and rats with nitroimidazole agents that are structurally similar to benznidazole in animal studies; it is unknown whether benznidazole is associated with carcinogenicity in humans. Genotoxicity (two-fold increase in chromosomal aberrations) of benznidazole has been demonstrated in one study of pediatric patients (11 months to 11 years) with Chagas disease.
• CNS effects: Paresthesia and/or peripheral neuropathy have been reported and may take several months to resolve; in general, these symptoms occur late in the course of treatment. Headache and dizziness have also been reported. Discontinue treatment if neurologic signs or symptoms occur.
• Dermatologic reactions: Serious skin and subcutaneous disorders (eg, acute generalized exanthematous pustulosis, toxic epidermal necrolysis, erythema multiforme, drug reaction with eosinophilia and systemic symptoms) have been reported. Extensive skin reactions (eg, rash [maculopapular, pruritic macules, eczema, pustules, erythematous, generalized], allergic dermatitis, exfoliative dermatitis) have also been reported, most cases occurring after ~10 days of treatment; most rashes resolved with treatment discontinuation. Mild to moderate dermatitis may be controlled with prednisone (AHA [Nunes 2018]). Discontinue treatment at first evidence of a serious cutaneous reaction or skin reactions presenting with systemic signs/symptoms (eg, lymphadenopathy, fever, purpura).
• Hematologic effects: Bone marrow depression (eg, neutropenia, thrombocytopenia, anemia, leukopenia) that resolved after treatment discontinuation has been reported. Use benznidazole with caution and under strict medical supervision in patients with hematological manifestations of bone marrow depression. Monitor CBC, as well as total and differential leukocyte counts, prior to initiation, during treatment, and after discontinuation of treatment.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Generic: 12.5 mg, 100 mg
Yes
Tablets (Benznidazole Oral)
12.5 mg (per each): $3.00
100 mg (per each): $3.60
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Oral: Tablets: Administer with or without food, approximately 12 hours apart. 100 mg tablet is scored and may be split to allow for doses in increments of 25 mg and 50 mg.
For patients unable to swallow tablets:
Slurry preparation: Note: Tablet strength used to prepare slurry is dependent on patient weight.
Place prescribed dose in a cup and add the specified volume of water; allow tablets to disintegrate over 1 to 2 minutes. Shake cup gently to mix and administer contents immediately. Rinse cup with additional water and administer entire amount; volume of rinse is based on tablet strength used; for slurry made with 12.5 mg tablets, rinse with an additional 10 mL; for 100 mg tablets, rinse with an additional 80 mL and repeat rinse with a second 80 mL (refer to manufacturer's labeling for additional information).
Patient weight <30 kg: Use 12.5 mg tablets:
50 mg dose: Dissolve 4 tablets in 40 mL water.
62.5 mg dose: Dissolve 5 tablets in 50 mL water.
75 mg dose: Dissolve 6 tablets in 60 mL water.
Patient weight ≥30 kg: Use 100 mg tablets:
100 mg dose: Dissolve 1 tablet in 80 mL water.
150 mg dose: Dissolve 1.5 tablets in 120 mL water.
200 mg dose: Dissolve 2 tablets in 160 mL water.
Oral: Administer with or without food, approximately 12 hours apart.
To make slurry using 12.5 or 100 mg tablets:
Place prescribed dose in a cup and add the specified volume of water (also refer to manufacturer's labeling):
12.5 mg tablets: 40 mL for 4 tablets, 50 mL for 5 tablets, or 60 mL for 6 tablets
100 mg tablets: 80 mL for 1 tablet, 120 mL for 1.5 tablets, or 160 mL for 2 tablets
Allow tablets to disintegrate over 1 to 2 minutes. Shake cup gently to mix and administer contents immediately. For 12.5 mg tablets, rinse cup with an additional 10 mL of water and administer entire amount. For 100 mg tablets, rinse cup with an additional 80 mL of water and administer entire amount; repeat this rinse with 80 mL and drink again.
This medication is not on the NIOSH (2024) list; however, it may meet the criteria for a hazardous drug. Benznidazole may cause carcinogenicity, teratogenicity (or other developmental toxicity), reproductive toxicity, and/or genotoxicity. Assess risk to determine appropriate containment strategy (USP-NF 2020).
Use appropriate precautions for receiving, handling, storage, preparation, dispensing, transporting, administration, and disposal. Follow NIOSH and USP 800 recommendations and institution-specific policies/procedures for appropriate containment strategy (NIOSH 2023; NIOSH 2024; USP-NF 2020).
Note: Facilities may perform risk assessment of some hazardous drugs to determine if appropriate for alternative handling and containment strategies (USP-NF 2020). Refer to institution-specific handling policies/procedures.
Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F). Protect from moisture.
Treatment of Chagas disease (American trypanosomiasis) caused by Trypanosoma cruzi (FDA approved in ages 2 to 12 years).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Disulfiram: Benznidazole may increase adverse/toxic effects of Disulfiram. In particular, the risk for CNS toxicities such as psychosis may be increased. Risk X: Avoid
Pregnancy testing is recommended prior to therapy in patients who could become pregnant; use effective contraception during treatment and for 5 days after the last dose of benznidazole.
Therapy with benznidazole prior to pregnancy in patients who test positive for T. cruzi antibodies may prevent congenital transmission. Patients who may become pregnant should be treated prior to conception (Álvarez 2017; Carlier 2011; Meymandi 2018; Rios 2020).
Based on data from animal reproduction studies, in utero exposure to benznidazole may cause fetal harm. Fetal malformations were observed following oral administration to pregnant rats in doses ≤3 and rabbits at doses ≤1 times the maximum recommended human dose.
Congenital transmission of Chagas disease may occur, and the actual risk may depend on stage of maternal disease and geographic location (Bittencourt 1992). Transmission rates are increased during an acute infection, or in patients with HIV or who are immunocompromised (Rios 2020). There are no specific recommendations for preventing vertical transmission of disease in patients who are already pregnant (Carlier 2011).
T. cruzi infection during pregnancy may be associated with adverse maternal and fetal outcomes. However, data related to the use of benznidazole for the treatment of acute Chagas disease in pregnancy are limited (consult with specialist prior to treatment). Treatment of chronic disease during pregnancy is not recommended and should be postponed until after delivery (HHS [OI adult 2024]; Meymandi 2018).
CBC and total and differential leukocyte counts prior to initiation, during treatment, and after discontinuation; pregnancy test prior to initiation in patients who could become pregnant; monitor for skin rash or neurologic signs/symptoms during treatment.
Inhibits the synthesis of DNA, RNA, and proteins within the T. cruzi parasite.
Absorption: Rapid (Bern 2007).
Distribution: Vd = 45 L.
Protein binding: ~44% to 60%.
Metabolism: Nitro reduction followed by glucuronidation.
Half-life elimination: ~13 hours.
Time to peak: Median: 2 hours.
Excretion: Urine (~68%) and feces (~21%).
