Mechanism of action
Syrup of ipecac contains alkaloids derived from the root of Cephaelis ipecacuanha, primarily emetine and cephaeline. These alkaloids induce emesis through a dual mechanism.
Local gastric irritation occurs when ipecac directly irritates the gastric mucosa, triggering afferent vagal signals that lead to vomiting. This peripheral effect contributes to nausea and the urge to vomit.
Central chemoreceptor trigger zone (CTZ) stimulation is the predominant mechanism. Absorbed alkaloids stimulate the chemoreceptor trigger zone (CTZ) in the area postrema of the medulla, which lacks a blood-brain barrier. This central stimulation coordinates the vomiting reflex through the vomiting center in the medulla.
Emetine also has significant toxicity. It inhibits protein synthesis at the ribosomal level, affects cellular respiration, and can cause myocardial damage with repeated exposure. Chronic use leads to myopathy, cardiomyopathy, and gastrointestinal damage.
- Ipecac is contraindicated in virtually all poisoning scenarios and has no current clinical indications.
- Mechanism: dual action via local gastric irritation and CTZ stimulation by emetine alkaloids.
- Major risk: aspiration pneumonitis, especially with petroleum distillates, caustics, or altered consciousness.
- Chronic ipecac abuse (eating disorders) causes emetine-induced cardiomyopathy, myopathy, and electrolyte disturbances.
- Ipecac removes <30% of gastric contents and delays definitive care (activated charcoal, transport).
- Never use in caustic, hydrocarbon, or sharp object ingestions, or in patients with seizures or decreased consciousness.
- Emetine has a long tissue half-life (40-50 days) and accumulates with repeated use, causing cumulative toxicity.
- Modern poisoning management: call poison control, supportive care, activated charcoal if appropriate within 1 hour.
Indications
Syrup of ipecac has no current approved indications. It was historically used in the home management of acute poisoning to empty gastric contents before arrival at a medical facility.
Major medical organizations, including the American Academy of Pediatrics, the American Association of Poison Control Centers, and the American Academy of Clinical Toxicology, have issued position statements recommending against its routine use in poisoning management since the early 2000s. The FDA requested voluntary market withdrawal in 2003.
Why ipecac is no longer recommended:
- Lack of efficacy: Studies show ipecac removes less than 30% of gastric contents, even when given within 30 minutes of ingestion. Efficacy drops sharply with time.
- Delays definitive care: Inducing vomiting delays administration of activated charcoal and transport to emergency facilities.
- Risk of aspiration: Vomiting increases the risk of aspiration pneumonitis, especially with petroleum distillates, caustics, or altered mental status.
- Contraindicated in many poisonings: Should never be used with corrosives, hydrocarbons, sharps, or in patients with decreased consciousness.
- No mortality benefit: No evidence that ipecac improves clinical outcomes or reduces mortality in poisoning cases.
Modern poisoning management emphasizes supportive care, activated charcoal when appropriate, whole bowel irrigation for specific toxins, and calling poison control centers.
Pharmacokinetics
When taken orally, ipecac acts within 15 to 30 minutes. The onset depends on gastric contents; a full stomach delays the effect.
Absorption: Emetine and cephaeline are absorbed from the gastrointestinal tract. With single doses, absorption is limited due to the rapid onset of vomiting. However, repeated doses lead to significant systemic absorption.
Distribution: Emetine accumulates in tissues, particularly liver, kidney, heart, and skeletal muscle. It has a long tissue half-life, estimated at 40 to 50 days.
Metabolism and excretion: Hepatic metabolism occurs, but emetine is excreted slowly, primarily via urine and feces. The prolonged tissue retention explains cumulative toxicity with repeated use.
Duration of effect: Vomiting typically lasts 20 to 60 minutes but can persist for several hours, especially with higher doses or in susceptible individuals. Protracted vomiting is a significant clinical problem.
Adverse effects
Syrup of ipecac carries substantial risks, particularly with repeated or excessive use.
Acute adverse effects
- Gastrointestinal: Prolonged vomiting and diarrhea lasting hours, leading to dehydration and electrolyte disturbances. Mallory-Weiss tears can occur from forceful vomiting.
- Aspiration: Risk of aspiration pneumonitis, especially if consciousness is impaired or the toxin itself predisposes to aspiration (e.g., hydrocarbons).
- Lethargy and drowsiness: Common after administration, complicating assessment of the poisoned patient.
- Interference with antidotes: Vomiting can prevent retention of orally administered activated charcoal or specific antidotes.
Chronic toxicity (with repeated use)
Chronic ipecac abuse, seen historically in patients with eating disorders (bulimia nervosa), causes severe systemic toxicity:
- Cardiomyopathy: Emetine is cardiotoxic. Chronic use leads to dilated cardiomyopathy, arrhythmias, heart failure, and sudden cardiac death. ECG changes include T-wave flattening, ST-segment depression, and QT prolongation.
- Myopathy: Proximal muscle weakness, rhabdomyolysis, and elevated creatine kinase due to skeletal muscle toxicity.
- Gastrointestinal damage: Chronic gastritis, esophagitis, and electrolyte imbalances (hypokalemia, hypocalcemia, hypomagnesemia) from persistent vomiting.
- Neurotoxicity: Peripheral neuropathy and encephalopathy have been reported.
Serious and life-threatening effects
- Severe dehydration and shock
- Cardiac arrest from emetine cardiotoxicity or electrolyte derangements
- Aspiration leading to acute respiratory distress syndrome
Contraindications and warnings
Syrup of ipecac is contraindicated in virtually all clinical scenarios. Specific contraindications include:
- Caustic ingestions: Acids or alkalis cause tissue damage; re-exposure during vomiting worsens esophageal and oropharyngeal injury.
- Petroleum distillate ingestions: High aspiration risk with substances like gasoline, kerosene, and lighter fluid. Aspiration causes severe chemical pneumonitis.
- Sharp object ingestion: Vomiting increases risk of perforation.
- Decreased level of consciousness: Patients with altered mental status cannot protect their airway, leading to aspiration.
- Seizures or risk of seizures: Many toxins (e.g., tricyclic antidepressants, stimulants) cause seizures; vomiting during a seizure is dangerous.
- Absent gag reflex: Inability to protect the airway contraindicates induced vomiting.
- Hemorrhagic diathesis or esophageal varices: Risk of life-threatening bleeding from forceful vomiting.
- Pregnancy: Risk to both mother and fetus; no indication justifies use.
- Infants under 6 months: Higher risk of aspiration and fluid/electrolyte disturbances.
Warnings
- Never keep ipecac at home: The American Academy of Pediatrics recommends discarding any ipecac in households.
- Do not use without poison control guidance: Even in the rare scenario where an emetic might theoretically be considered, modern poison management does not support ipecac use.
- Eating disorder alert: Chronic abuse is a medical emergency requiring cardiac evaluation.
Drug interactions
Syrup of ipecac has several clinically significant interactions, though its obsolete status makes these largely historical.
- Activated charcoal: Ipecac-induced vomiting can expel activated charcoal before it binds the toxin, negating its benefit. If both are used (not recommended), activated charcoal should be given after vomiting has ceased, but this delays definitive care.
- Antiemetics: Ondansetron, metoclopramide, and phenothiazines (promethazine, prochlorperazine) antagonize ipecac's emetic effect. Concurrent use is counterproductive.
- Milk and carbonated beverages: Traditionally given with ipecac to facilitate vomiting, but milk may delay gastric emptying and reduce efficacy. Modern guidance advises against this practice.
- Cardiotoxic drugs: Emetine's cardiotoxicity is additive with other QT-prolonging agents (antiarrhythmics, macrolides, antipsychotics). Chronic ipecac users on such medications face increased arrhythmia risk.
- Neuromuscular blocking agents: Emetine can potentiate neuromuscular blockade due to its effects on skeletal muscle.
No formal drug interaction studies exist because ipecac is no longer used therapeutically. Clinicians should focus on supportive care and modern toxicology interventions rather than navigating ipecac interactions.
Clinical pearls
- Ipecac is obsolete in poisoning management. The correct answer on exams when asked about ipecac use is almost always "do not administer" or "contraindicated."
- Call poison control first: The number in the United States is 1-800-222-1222. Poison control centers provide evidence-based guidance and do not recommend ipecac.
- Activated charcoal is preferred when gastrointestinal decontamination is indicated, and even charcoal has limited benefit unless given within 1 hour of ingestion for appropriate toxins.
- Recognize chronic ipecac abuse: Think of ipecac toxicity in patients with eating disorders presenting with unexplained cardiomyopathy, proximal myopathy, or refractory electrolyte abnormalities. Obtain a careful psychiatric and dietary history.
- Emetine cardiotoxicity is insidious: ECG changes may appear before symptoms. Chronic users need cardiac monitoring, echocardiography, and troponin levels.
- Ipecac does not prevent toxin absorption: By the time ipecac induces vomiting (15-30 minutes), significant absorption has often occurred. It is not a reliable decontamination method.
- Aspiration is the most feared acute complication: Always ensure airway protection before considering any intervention that induces vomiting (which, again, should not include ipecac).
- Home management of poisoning: Focus on preventing access to toxins (childproofing, safe storage), calling poison control immediately, and transporting to an emergency department when indicated. Ipecac has no role in modern home first aid.
- Exam tip: USMLE and similar exams may present ipecac as a historical distractor in poisoning cases. The correct management almost never involves ipecac; look for answers emphasizing supportive care, activated charcoal, or specific antidotes.
Practice questions
1. A 3-year-old girl is brought to the emergency department 20 minutes after ingesting an unknown quantity of her grandmother's hydrocodone tablets. The child is alert and crying. Her grandmother wants to know if syrup of ipecac should be given at home before coming to the hospital. What is the most appropriate advice regarding ipecac use in this scenario?
2. A 22-year-old woman with a history of bulimia nervosa presents with progressive fatigue, shortness of breath, and lower extremity edema over 3 months. Physical examination reveals bilateral crackles, an S3 gallop, and proximal muscle weakness. ECG shows sinus tachycardia with T-wave flattening. Echocardiography demonstrates dilated cardiomyopathy with an ejection fraction of 30%. Which substance is most likely responsible for her condition?
3. A mother calls poison control after her 5-year-old son ingested drain cleaner (sodium hydroxide) 10 minutes ago. The child is crying and complaining of mouth and chest pain. She has syrup of ipecac at home and asks if she should give it. What is the most appropriate recommendation?
Frequently asked questions
How does syrup of ipecac work?
Syrup of ipecac induces vomiting through a dual mechanism: local gastric irritation and central stimulation of the chemoreceptor trigger zone (CTZ) in the medulla. The active alkaloids, emetine and cephaeline, irritate the stomach lining and stimulate the CTZ in the area postrema, triggering the vomiting reflex. Vomiting typically begins within 15 to 30 minutes of ingestion.
What are the side effects of ipecac syrup?
Acute side effects include prolonged vomiting, diarrhea, dehydration, lethargy, and aspiration pneumonitis. Chronic use causes severe toxicity: emetine-induced cardiomyopathy (heart failure, arrhythmias), skeletal myopathy (muscle weakness, elevated creatine kinase), and gastrointestinal damage. Electrolyte imbalances such as hypokalemia are common with repeated vomiting. Chronic abuse can lead to sudden cardiac death.
Is syrup of ipecac still used for poisoning?
No, syrup of ipecac is no longer recommended for poisoning management. Major medical organizations, including the American Academy of Pediatrics and the American Association of Poison Control Centers, have advised against its use since the early 2000s. It is ineffective (removes <30% of stomach contents), delays definitive care, and increases the risk of aspiration. Modern treatment emphasizes calling poison control, supportive care, and activated charcoal when appropriate.
Why was ipecac discontinued?
Ipecac was discontinued because studies demonstrated it lacks clinical efficacy and poses significant risks. It does not improve outcomes in poisoning cases, removes minimal gastric contents, delays transport and treatment with activated charcoal or antidotes, and increases the risk of aspiration pneumonitis. Additionally, it is contraindicated in many common poisonings (caustics, hydrocarbons, altered consciousness). The FDA requested voluntary withdrawal in 2003, and it is now considered obsolete.
What happens if you use ipecac chronically?
Chronic ipecac use, historically seen in patients with bulimia nervosa, causes severe systemic toxicity from emetine accumulation. Cardiac effects include dilated cardiomyopathy, heart failure, arrhythmias, ECG changes (T-wave flattening, QT prolongation), and sudden death. Skeletal myopathy presents as proximal muscle weakness and elevated creatine kinase. Gastrointestinal damage, peripheral neuropathy, and life-threatening electrolyte imbalances (hypokalemia, hypomagnesemia) also occur. Emetine has a long tissue half-life (40-50 days), leading to cumulative toxicity.
Related drugs
Sources and further reading
DailyMed (FDA labels)StatPearls (NCBI Bookshelf)MedlinePlusWHO ATC/DDD index: R05CA04
Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.