Nicotine poisoning may occur in children after they ingest tobacco or drink saliva expectorated by a tobacco chewer (which is often collected in a can or other containers), in children or adults after accidental or suicidal ingestion of nicotine-containing pesticides (eg, Black Leaf 40, which contains 40% nicotine sulfate), occasionally after cutaneous exposure to nicotine, such as occurs among tobacco harvesters (“green tobacco sickness”), and after ingestions of nicotine-containing liquids used in electronic cigarettes. Nicotine chewing gum, transdermal delivery formulations, and nicotine nasal spray, inhalers, and lozenges are widely available as adjunctive therapy for smoking cessation. Nicotine is found in various smokeless tobacco products (snuff and chewing tobacco), and recently in oral pouches containing nicotine without tobacco. Alkaloids similar to nicotine (anabasine, cytisine, coniine, and lobeline) are found in several plant species (see “Plants,”). Neonicotinoid insecticides (imidacloprid and others) are widely used both in agriculture and for flea control in dogs and cats.

1. Nicotine binds to nicotinic cholinergic receptors, resulting initially, via actions on autonomic ganglia, in predominantly sympathetic nervous stimulation. With higher doses, parasympathetic stimulation and then ganglionic and neuromuscular blockade may occur. Direct effects on the brain may also result in vomiting and seizures.
2. Pharmacokinetics. Nicotine is absorbed rapidly by all routes and enters the brain quickly. It is rapidly metabolized and to a lesser extent excreted in the urine, with a half-life of 120 minutes. Neonicotinoids penetrate the CNS less well than nicotine and therefore are less toxic than nicotine at low levels of exposure.

The bioavailability of ingested nicotine is about 30-40% due to first-pass metabolism in the liver and spontaneous vomiting. The LD₅₀ for nicotine is estimated to be between 6.5 and 13 mg/kg. Rapid absorption of 2-5 mg can cause nausea and vomiting, particularly in a person who does not use tobacco or other nicotine products habitually.

1. Tobacco. Cigarette tobacco contains about 1.5% nicotine, or 10-15 mg of nicotine per cigarette. Moist snuff is also about 1.5% nicotine; most containers hold 30 g of tobacco. Chewing tobacco contains 2.5-8% nicotine. In a child, ingestion of one cigarette or three cigarette butts should be considered potentially toxic, although serious poisoning from ingestion of cigarettes is very uncommon. Ingestions of smokeless tobacco products can cause nicotine poisoning in infants and children.
2. Electronic cigarettes. E-cigarettes are devices that heat a solution, usually containing nicotine, propylene glycol and/or vegetable glycerin, to generate an aerosol that is inhaled like a tobacco cigarette. Many devices are refillable, and the refills (e-liquids) can be purchased in small bottles. Most e-liquids are flavored and potentially attractive to children. The nicotine content of e-liquids ranges from 3 to more than 50 mg/mL. A 5-mL bottle can contain 100 mg or more nicotine, which could be lethal to an infant or small child. The number of poison center calls regarding nicotine toxicity from e-cigarettes has risen exponentially in recent years, with 50% of calls involving children 5 years or younger. The most common routes of exposure are ingestion, inhalation, ocular exposure, and skin exposure. The most common toxicities are nausea, vomiting, and eye irritation. There have been a few deaths from ingestion or injection of e-liquids. Ingestion of nicotine e-liquid containing cartridges has been reported, but without toxicity.
3. Oral nicotine products (nonmedicinal) contain from 2 to 8 mg nicotine per pouch.
4. Nicotine gum contains 2 or 4 mg per piece, but owing to its slow absorption and high degree of first-pass metabolism, nicotine intoxication from these products is uncommon.
5. Transdermal nicotine patches deliver an average of 5-22 mg of nicotine over the 16-24 hours of intended application, depending on the brand and size. Transdermal patches may produce intoxication in light smokers or in nonsmokers, particularly children to whom a used patch inadvertently sticks. Ingestion of a discarded patch may also potentially produce poisoning.
6. Nicotine nasal spray delivers about 1 mg (a single dose is one spray in each nostril).
7. Nicotine inhaler systems consist of a plastic mouthpiece and replaceable cartridges containing 10 mg of nicotine. If accidentally ingested, the cartridge will release the nicotine slowly, and no serious intoxication has been reported.
8. Nicotine lozenges contain 2-4 mg of nicotine, and ingestion can cause serious toxicity in a child.
9. Neonicotinoids are relatively nontoxic in small doses, but intentional ingestions of 30 mL or more have been associated with serious and even fatal toxicity.

Nicotine intoxication commonly causes dizziness, nausea, vomiting, pallor, and diaphoresis. Abdominal pain, salivation, lacrimation, diarrhea, and muscle weakness may be noted. Pupils may be dilated or constricted. Confusion, agitation, lethargy, and convulsions are seen with severe poisonings. Initial tachycardia and hypertension may be followed by bradycardia and hypotension. Respiratory muscle weakness with respiratory arrest is the most likely cause of death. Symptoms usually begin within 15 minutes after acute liquid nicotine seen with higher doses or cutaneous exposure, with the latter resulting in continued absorption from the skin. Delayed onset and prolonged symptoms may also be seen with nicotine gum or transdermal patches.

Is suggested by vomiting, pallor, and diaphoresis, although these symptoms are nonspecific. The diagnosis is usually made by a history of tobacco, insecticide, or therapeutic nicotine product exposure. Nicotine poisoning should be considered in a small child with unexplained vomiting whose parents consume tobacco or e-cigarettes.

1. Specific levels. Nicotine and its metabolite cotinine are detected in comprehensive urine toxicology screens, but because they are so commonly present, they will not usually be reported unless a specific request is made. Commercial screening immunoassays for urinary cotinine are also available but are not widely implemented in hospital-based clinical laboratories for the reasons given above. Serum levels of nicotine can be performed but are not useful in acute management. Anabasine levels (found in Nicotiana glauca, or tree tobacco) can be measured by some laboratories.
2. Other useful laboratory studies include electrolytes, glucose, creatine kinase, and arterial blood gases or oximetry.

1. Emergency and supportive measures
   1. Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen.
   2. Treat seizures, coma, hypotension, hypertension, and arrhythmias if they occur.
   3. Observe for at least 4-6 hours to rule out delayed toxicity, especially after skin exposure. For ingestion of intact gum, tablets, or transdermal patches, observe for a longer period (up to 12-24 hours).
2. Specific drugs and antidotes
   1. Mecamylamine is a specific antagonist of nicotine actions; however, it is available only in tablets, a form not suitable for a patient who is vomiting, convulsing, or hypotensive.
   2. Signs of muscarinic stimulation (eg, bradycardia, salivation, wheezing), if they occur, may respond to atropine.
3. Decontamination. Caution: Rescuers should wear appropriate skin-protective gear when treating patients with oral or skin exposure to liquid nicotine.
   1. Skin and eyes. Remove all contaminated clothing and wash exposed skin with copious soap and water. Irrigate exposed eyes with copious saline or water.
   2. Ingestion. Administer activated charcoal orally if conditions are appropriate (see Table I-37,). Gastric lavage is not necessary after tobacco ingestions if activated charcoal can be given promptly. Consider gastric lavage for large recent ingestions of liquid nicotine
      1. For asymptomatic small-quantity cigarette ingestions, no gut decontamination is necessary.
      2. For ingestion of transdermal patches, nicotine-containing e-cigarette cartridges, or large amounts of nicotine gum, consider repeated doses of charcoal and whole-bowel irrigation.
4. Enhanced elimination. These procedures are not likely to be useful because the endogenous clearance of nicotine is high, its half-life is relatively short (2 hours), and the volume of distribution is relatively large.