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Pediatric Reference

Metronidazole Side EffectsComprehensive Pediatric Safety Guide

Metronidazole side effects are usually mild and include GI upset and metallic taste.

4 Categories
6 Clinical Sources
Evidence-Based
Back to Metronidazole Overview

Essential Information

1

Take with food and rinse the mouth after dosing to limit metallic taste.

2

Call for numbness, tingling, or unsteady gait.

3

Avoid alcohol to prevent disulfiram-like reactions.

Clinical Overview

Serious reactions like neuropathy or encephalopathy are rare and typically linked to high doses or long courses.

Side Effect Categories

4 Systems

Gastrointestinal

2 documented effects

Total Sources: 2

Nausea

Incidence: Common
Onset: Early in therapy
mild
1 sources
Duration

Not specified

Management

Give with meals; offer bland snacks.

Monitoring Guidelines

Call if vomiting persists or child cannot keep liquids down.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Metallic taste

Incidence: Common
Onset: Not specified
mild
1 sources
Duration

Not specified

Management

Rinse mouth or chase with flavored drink.

Monitoring Guidelines

Monitor for symptom escalation or new adverse effects.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Neurologic

2 documented effects

Total Sources: 2

Headache

Incidence: Common
Onset: Not specified
mild
1 sources
Duration

Not specified

Management

Supportive care; ensure hydration.

Monitoring Guidelines

Monitor for symptom escalation or new adverse effects.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Peripheral neuropathy

Incidence: Rare
Onset: Usually after prolonged therapy
serious
1 sources
Duration

Not specified

Management

Stop drug and evaluate; may require neurologic consult.

Monitoring Guidelines

Ask about new numbness or tingling weekly during long courses.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Dermatologic

1 documented effect

Total Sources: 1

Rash/Urticaria

Incidence: Uncommon
Onset: Not specified
moderate
1 sources
Duration

Not specified

Management

Stop medication and contact clinician; evaluate for allergy.

Monitoring Guidelines

Monitor for symptom escalation or new adverse effects.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Other

1 documented effect

Total Sources: 1

Disulfiram-like reaction with alcohol

Incidence: Rare
Onset: Not specified
moderate
1 sources
Duration

Not specified

Management

Avoid alcohol; seek care if severe flushing, tachycardia, or vomiting occurs.

Monitoring Guidelines

Monitor for symptom escalation or new adverse effects.

1 clinical sources• PubMed • Clinical Guidelines • FDA

Parent Communication Guide

Age-Appropriate Explanations

Infants (0-12 months)

Give metronidazole exactly as prescribed. Call if your baby vomits multiple doses or becomes unusually sleepy.

Toddlers (1-3 years)

This medicine helps clear stomach bugs. Keep it out of reach, use the dosing device, and let us know if they refuse medicine because of the taste.

Children (4-12 years)

Metronidazole can cause a metallic taste or mild stomach upset. Take it with food if instructed and avoid mouthwash or cough syrup that contains alcohol.

Adolescents (13+ years)

No alcohol—including mouthwash or gel sanitizers—while on metronidazole or for 72 hours after. Call if you feel numbness, tingling, or severe stomach pain.

Common Parent Concerns

Q: Metallic taste

A: Chill the dose, chase with juice, or brush teeth afterward to mask the taste.

When to validate: Call if your child refuses doses despite strategies.

Q: Numbness or tingling

A: Stop the medicine and contact the care team; neuropathy, while rare, requires prompt assessment.

When to validate: Emergent review if weakness, balance issues, or seizures develop.

Clinical Decision Support

Severity Assessment Framework

Gauge metronidazole adverse reactions with emphasis on neuropathy, C. difficile colitis, and disulfiram-like responses.

Mild
Indicators: Metallic taste, mild nausea, or headache, No neurologic findings, No alcohol exposure
Action: Continue therapy, reinforce taste mitigation and hydration, revisit monitoring at next contact.
Moderate
Indicators: Persistent vomiting or diarrhea (>24 hours), New paresthesias or gait changes without weakness, Caregiver concern about accidental alcohol intake or interacting medicines
Action: Hold further doses pending assessment, perform focused neuro exam, review medication list, obtain stool testing if diarrhea concerning for C. difficile, consider switch if symptoms persist.
Severe
Indicators: Objective neuropathy, seizures, encephalopathy, or severe autonomic instability, Suspected disulfiram-like reaction (flushing, tachycardia, hypotension), Severe cutaneous or hepatic injury
Action: Stop metronidazole immediately, escalate to emergency care, treat complications (IV fluids, benzodiazepines), and involve neurology or infectious disease.

Treatment Decision Guidelines

Immediate Discontinuation

  • • Peripheral neuropathy, seizures, or cerebellar signs
  • • Severe hypersensitivity or Stevens-Johnson syndrome
  • • Fulminant colitis or toxic megacolon
  • • Confirmed disulfiram-like reaction

Consider Alternatives

  • • Persistent GI intolerance despite mitigation
  • • Drug interactions that cannot be safely managed (warfarin instability, chronic alcohol use)
  • • Caregiver inability to avoid alcohol-containing products

Dose Modification

  • • Renal impairment requiring extended dosing interval
  • • Hepatic dysfunction prompting lower total daily dose
  • • Transition to IV therapy or alternative agent when oral intolerance limits adherence

Clinical References

Metronidazole Tablets and Suspension•DailyMed (2024)Label
Metronidazole•MedlinePlus (2024)Drug information

Frequently Asked Questions

Parent and clinician concerns about Metronidazole