Gastric Lavage and Activated Charcoal After 9 Hours of Rodenticide Ingestion
Direct Answer
Neither gastric lavage nor activated charcoal is indicated 9 hours after rodenticide ingestion, as both interventions are ineffective beyond 1-2 hours post-ingestion and the focus should shift entirely to monitoring for coagulopathy and treating complications. 1
Time-Based Algorithm for Gastrointestinal Decontamination
Within 1 Hour of Ingestion
- Activated charcoal alone (50g in adults, 1 g/kg in children) is the preferred decontamination method if the patient has an intact airway 2, 3, 4
- Gastric lavage may be considered only for life-threatening ingestions presenting within the first hour, though evidence does not support routine combination therapy 5, 6
- Gastric lavage is NOT recommended for rodenticide poisoning at any time point 1
1-2 Hours Post-Ingestion
- Activated charcoal may still provide some benefit, with median reduction in drug absorption of approximately 66% at 1 hour but declining rapidly thereafter 6
- Maximum benefit window extends to 2 hours for most substances, though efficacy drops to only 22.7% reduction in absorption 6
Beyond 2 Hours Post-Ingestion
- No gastrointestinal decontamination is recommended as absorption is essentially complete 5, 7
- The exception is sustained-release formulations or drugs with delayed absorption, where activated charcoal may be considered up to 3-4 hours 3
At 9 Hours (Your Patient)
- Both gastric lavage and activated charcoal are contraindicated as they provide no benefit and only increase risk of complications including aspiration and need for intubation 1, 5
Management Focus for Late Presentation (9 Hours)
Immediate Assessment
- Evaluate for signs of coagulopathy: bleeding, bruising, petechiae 1
- Obtain baseline prothrombin time (PT/INR) immediately 1
- Determine exact rodenticide type and estimated dose ingested 1
Risk Stratification
Refer immediately to emergency department if: 1
- Any symptoms of bleeding or coagulopathy present
- Suspected self-harm or intentional ingestion
- Chronic/repeated ingestion
- Patient on therapeutic anticoagulation
- Ingestion of ≥1 mg active ingredient
Outpatient monitoring acceptable if: 1
- Unintentional ingestion <1 mg active ingredient
- Completely asymptomatic
- Reliable follow-up available
- Repeat PT/INR can be obtained at 48-72 hours
Critical Timing for Coagulopathy Monitoring
- Repeat PT/INR at 48-72 hours post-ingestion regardless of initial normal values, as anticoagulant effects are delayed 1
- Do NOT administer vitamin K prophylactically before documented coagulopathy 1
Common Pitfalls to Avoid
Decontamination Errors
- Never delay transport to administer activated charcoal in patients requiring emergency department evaluation 1
- Do not attempt gastric lavage in the out-of-hospital setting or after 1-2 hours 1, 5
- Avoid ipecac syrup entirely—it is no longer recommended for any poisoning 4, 1
Monitoring Errors
- Do not rely on initial normal PT/INR to rule out significant ingestion—coagulopathy develops over 24-72 hours with long-acting anticoagulant rodenticides 1
- Do not discharge patients with ≥1 mg ingestion without arranging definitive coagulopathy assessment 1
Treatment Errors
- Do not give prophylactic vitamin K before laboratory confirmation of coagulopathy 1
- Do not use combination gastric lavage plus activated charcoal, as studies show no additional benefit and increased complications including higher ICU admission rates 5, 6
Evidence Quality Note
The recommendation against decontamination at 9 hours is based on high-quality evidence from multiple sources: a 2007 evidence-based consensus guideline specifically for rodenticide poisoning 1, supported by pharmacokinetic studies demonstrating minimal benefit beyond 2 hours 6, and general poisoning guidelines emphasizing the narrow therapeutic window for gastrointestinal decontamination 5, 7.