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Benznidazole Side Effects

For the Consumer

Applies to benznidazole: oral tablet

Along with its needed effects, benznidazole may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking benznidazole:

More common
  • Black, tarry stools
  • chest pain
  • chills
  • cough
  • fever
  • painful or difficult urination
  • rash
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Less common
  • Burning, numbness, tingling, or painful sensations
  • headache
  • tremors
  • unsteadiness or awkwardness
  • weakness in the arms, hands, legs, or feet
Incidence not known
  • Bleeding gums
  • blistering, peeling, or loosening of the skin
  • blood in the urine or stools
  • dark urine
  • diarrhea
  • difficulty in moving
  • general tiredness and weakness
  • inability to concentrate
  • itching
  • light-colored stools
  • muscle pain or stiffness
  • nausea
  • pain, swelling, or redness in the joints
  • pinpoint red spots on the skin
  • red, irritated eyes
  • seizures
  • swelling of the eyelid, arms, or legs
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • temporary disorientation
  • temporary loss of memory
  • trouble sleeping
  • upper right abdominal pain
  • vomiting
  • yellow eyes and skin

Some side effects of benznidazole may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Decreased appetite
  • decreased weight
  • stomach pain
Incidence not known
  • Bone pain
  • dry mouth
  • loss of sense of taste
  • loss of strength
  • muscle aching or cramping

For Healthcare Professionals

Applies to benznidazole: oral tablet

General

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]

Gastrointestinal

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

Dermatologic

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]

Hematologic

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]

Metabolic

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

Other

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]

Hepatic

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

Musculoskeletal

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

Psychiatric

Postmarketing reports: Insomnia, temporary disorientation[Ref]

Ocular

Postmarketing reports: Eyelid edema[Ref]

References

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

Further information

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

Some side effects may not be reported. You may report them to the FDA.

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