What is the mechanism of action of ipecac and its current role in the management of oral poison ingestion?

Ipecac Mechanism of Action and Clinical Role

Ipecac syrup should not be administered for poison ingestion—it works by inducing vomiting through local gastric irritation and central chemoreceptor trigger zone stimulation, but provides no clinical benefit and may cause harm. 1

Mechanism of Action

Ipecac contains two alkaloids (emetine and cephaline) that induce emesis through a dual mechanism 2:

• Local gastric irritation: Direct irritant effect on the gastric mucosa stimulates afferent vagal pathways 2
• Central stimulation: Systemic absorption triggers the chemoreceptor trigger zone in the medulla oblongata 2
• Onset: Vomiting typically occurs 15-30 minutes after administration 2

Why Ipecac Is No Longer Recommended

Evidence Against Routine Use

The 2010 American Heart Association/American Red Cross guidelines explicitly state ipecac should NOT be administered for toxin ingestions (Class III recommendation, Level of Evidence B). 1

Key evidence demonstrating lack of benefit 1, 2, 3, 4:

• No improvement in clinical outcomes: Multiple clinical studies found no reduction in morbidity, mortality, or healthcare utilization 1, 3
• Highly variable efficacy: Experimental studies showed marker removal ranged widely and diminished significantly with time—even under optimal conditions, ipecac recovered only 28% of ingested material at 10 minutes post-ingestion 2, 5
• Inferior to alternatives: Gastric lavage (when indicated) recovered 45% versus ipecac's 28% in controlled studies 5

Documented Harms

Ipecac administration causes specific complications that worsen patient outcomes 1, 3, 4:

• Intractable emesis: Prolonged vomiting delays definitive care and transport to advanced medical facilities 1
• Interference with effective treatments: Delays or reduces effectiveness of activated charcoal, oral antidotes, and whole bowel irrigation 3, 4
• Aspiration risk: Particularly dangerous in patients with decreased consciousness or after ingesting hydrocarbons/corrosives 4

Current Clinical Approach to Poison Ingestion

Immediate Actions

Contact the Poison Help hotline (1-800-222-1222) immediately—do NOT administer anything by mouth unless specifically directed by poison control or EMS. 1, 6, 7

The evidence-based algorithm 1, 6:

1. Assess for life-threatening signs: Altered consciousness, seizures, respiratory distress, persistent vomiting 1
2. Activate EMS immediately if any concerning symptoms present 1
3. Call poison control for all ingestions to determine appropriate management 1, 6
4. Do NOT give water, milk, or any substance by mouth unless poison control directs—no human studies show clinical benefit and administration may cause emesis and aspiration 1, 7

Role of Activated Charcoal

Activated charcoal should NOT be administered routinely by first responders (Class IIb recommendation, Level of Evidence C). 1

When charcoal may be considered (only under poison control/EMS direction) 1, 6:

• Patient has intact airway and protective reflexes 6
• Presents within 1-2 hours of toxic ingestion 6
• Substance is known to be adsorbed by charcoal 6
• Contraindications: Caustic ingestions, hydrocarbons, impaired consciousness without secured airway 6

Critical Pitfalls to Avoid

Common errors that worsen outcomes 1, 7:

• Never induce vomiting with any method—no clinical benefit and increases aspiration risk 1, 7
• Never attempt "dilution" with water/milk—animal studies showed theoretical benefit but no human studies demonstrate improved outcomes 1
• Never delay EMS activation while attempting home interventions 7
• Never administer activated charcoal without professional guidance—majority of patients cannot tolerate recommended doses and reports document harm 1

Special Considerations

For caustic or hydrocarbon ingestions, ipecac is absolutely contraindicated—induced vomiting causes re-exposure of the esophagus to the corrosive agent and dramatically increases aspiration risk. 4

The availability of ipecac has appropriately diminished as evidence mounted against its use 3. The 2004 and 2013 position papers from the American Academy of Clinical Toxicology and European Association of Poison Centres found no new evidence to support any role for ipecac in modern toxicology practice 3, 4.