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Benznidazole Side Effects

Applies to benznidazole: oral tablet


This drug was used in 55 pediatric patients (aged 6 to 12 years) and 64 pediatric patients (aged 7 to 12 years) during 2 controlled trials and 37 pediatric patients (aged 2 to 12 years) in an uncontrolled trial; each patient had chronic indeterminate Chagas disease.

In 1 controlled trial, this drug was discontinued due to at least 1 side effect in 5 of 55 patients; such side effects included abdominal pain, nausea, vomiting, rash, decreased appetite, headache, and elevated transaminases. The most commonly reported side effects in this trial were abdominal pain, rash, decreased weight, and headache.

In the uncontrolled trial, rash, leukopenia, urticaria, eosinophilia, decreased appetite, and neutropenia were reported in 6 of 19 pediatric patients (aged 2 to 6 years); such side effects were similar to those reported in the overall population of 37 patients.[Ref]


Very common (10% or more): Abdominal pain (up to 25%)
Common (1% to 10%): Nausea, vomiting, diarrhea
Postmarketing reports: Epigastric pain, dry mouth[Ref]


Extensive skin reactions (such as rash [maculopapular, pruritic macules, eczema, pustules, erythematous, generalized, allergic dermatitis, exfoliative dermatitis]) have been reported. Most cases occurred after about 10 days of therapy; most rashes resolved with discontinuation of therapy.[Ref]

Very common (10% or more): Rash (16%), urticaria (16%), skin lesions (11%)
Frequency not reported: Severe skin and soft tissue reactions, serious skin and subcutaneous disorders (including eosinophilic drug reaction), extensive skin reactions (such as rash [maculopapular, pruritic macules, eczema, pustules, allergic dermatitis])
Postmarketing reports: Maculopapular cutaneous eruptions, erythematous plaques, generalized rash, erythematous rash, pruritic rash, blistering eruptions, peeling skin, exfoliative dermatitis, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, erythema multiforme, drug reaction with eosinophilia and systemic symptoms[Ref]


Very common (10% or more): Leukopenia (16%), eosinophilia (16%), neutropenia (16%)
Frequency not reported: Hematological manifestations of bone marrow depression (such as neutropenia, thrombocytopenia, anemia, leukopenia)
Postmarketing reports: Lymphadenopathy, thrombocytopenia, granulocytopenia, agranulocytosis[Ref]


Very common (10% or more): Decreased appetite (up to 16%)
Common (1% to 10%): Anorexia[Ref]


Very common (10% or more): Decreased weight (13%)
Frequency not reported: Genotoxicity
Postmarketing reports: Fever, asthenia, fatigue, generalized edema, edema in the extremities, elevated alkaline phosphatase[Ref]

Nervous system

Common (1% to 10%): Headache, dizziness, peripheral neuropathy, tremor
Postmarketing reports: Paresthesia, hypoesthesia, headaches, convulsions, inability to concentrate, temporary amnesia, ageusia[Ref]


Common (1% to 10%): Elevated transaminases
Postmarketing reports: Hepatitis, toxic hepatitis, elevated bilirubin[Ref]


Common (1% to 10%): Arthralgia
Postmarketing reports: Myalgia, musculoskeletal pain, migratory arthritis[Ref]


Postmarketing reports: Insomnia, temporary disorientation[Ref]


Postmarketing reports: Eyelid edema[Ref]


1. "Product Information. Benznidazole (benznidazole)." Everett Laboratories Inc, West Orange, NJ.

Some side effects of benznidazole may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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