Correspondence

Pesticide-like Poisoning from a Prescription Drug

N Engl J Med 2005; 353:317-318July 21, 2005

Article

To the Editor:

Acetylcholinesterase inhibitors have long been known for their use as pesticides. Since the 1990s, acetylcholinesterase-inhibiting pharmaceuticals (donepezil, tacrine, galantamine, and rivastigmine) have been used to treat Alzheimer's disease; they are currently being investigated as a treatment for dementia associated with Parkinson's disease in adults1 and with Tourette's syndrome and autistic and attention deficit–hyperactivity disorders in children.2,3 Wider use of this class of medications for a broader variety of disorders increases the possibility of pesticide-like poisoning from a prescribed medication. We report a case of such poisoning.

A healthy 11-month-old girl (weight, 7.5 kg) presented to a pediatric hospital with rapid onset of general weakness during a period of several hours. The infant had been discharged from the same hospital three days earlier after undergoing intravenous rehydration for gastroenteritis. On arrival at the second visit, she was hypotonic, hyporeflexic, and had miosis and a weak cry. She had had no diarrhea, wet diapers, or lacrimation. Neurology was consulted; a workup was initiated to rule out botulism and Guillain–Barré syndrome. The levels of electrolytes, blood urea nitrogen, creatinine, and glucose and the complete blood count were normal, as were the results of liver-function tests, electrocardiography, urinalysis, computed tomography of the head, and lumbar-puncture studies. There was no family history of myasthenia gravis or neuromuscular disorders. The family did not keep plants in the home, and they did not use rodenticides. Since it was winter in New England, there was no outdoor exposure to insecticides. Further questioning revealed that the patient's mother had found the child chewing a capsule containing rivastigmine, a drug taken by the grandmother, earlier in the day, but because of history-taking and language problems (the family was first-generation Vietnamese), the connection was not initially made between the drug exposure and the child's symptoms.

Rivastigmine is a centrally acting carbamate derivative and a reversible inhibitor of acetylcholinesterase that produces a self-limited cholinergic constellation of signs and symptoms consistent with a specific drug class or xenobiotic poisoning that rarely lasts more than 24 hours. Muscarinic effects may be treated with atropine and nicotinic effects with oximes such as pralidoxime. However, muscarinic effects are often absent in children,4 as was the case with our patient, and the administration of oximes does not appear to speed recovery from nicotinic effects in such cases.5 Our patient improved with supportive care alone, and by 24 hours after she had ingested the drug, she was sitting without assistance; by 48 hours, she had regained her normal strength and was discharged.

Our patient had notable, predominantly nicotinic cholinergic effects after exposure to a nonpesticide carbamate acetylcholinesterase inhibitor intended for the treatment of memory-impaired adults. As the use of this class of drugs becomes more widespread, we want to alert clinicians to consider such exposure when evaluating weakness of rapid onset or any case of pesticide-like poisoning in which pesticide exposure is unlikely.

Melisa W. Lai, M.D.
Children's Hospital, Boston, MA 02115
melisa.lai@alumni.brown.edu

Matthew Moen, Pharm.D.
Massachusetts College of Pharmacy and Health Sciences, Boston, MA 02115

Michele Burns Ewald, M.D.
Children's Hospital, Boston, MA 02115

5 References

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Citing Articles (1)

Citing Articles

1. 1

   (2006) Current awareness: Pharmacoepidemiology and drug safety. Pharmacoepidemiology and Drug Safety 15:1, i-xii
   CrossRef