SchoolNurse.com:Acetaminophen Safety

Acetaminophen Safety

This article reviewed acetaminophen toxicity and measures to prevent overdose.

When excessive acetaminophen is taken, the normal metabolic pathways become saturated. The excess is metabolized through an alternative pathway (glutathione conjugation), but NAPQI (N-acetyl-p-benzoquinoneimine) accumulates and binds to liver cell proteins, causing cellular death. A single dose over 140 mg/Kg in children requires immediate treatment with N-acetylcysteine therapy to prevent hepatic failure.

Little is known about chronic, lower dose toxicity. There are reported cases of children receiving adult doses despite clear product labels and of fatalities with doses less than 140 mg/Kg. In one study, only 30 of 100 parents could accurately calculate the dose. While 66% said they gave their children Tylenol¢ç, only 8% said they gave "acetaminophen." Caretakers do not realize multiple sources of the substance, thus risking cumulative doses when multiple medications are given.

Viral illnesses, dehydration, and limited protein intake (from poor appetite) reduce the body's glutathione level and increase the degree of acetaminophen toxicity. Some medications, e.g., phenobarbital, phenytoin, rifampin, and isoniazid, affect liver enzyme function, increasing the level of toxic NAPQI.

Lack of knowledge about acetaminophen toxicity can turn an adolescent suicide gesture into inadvertent death or liver damage. In a survey of American and British teens, over 90% knew that an overdose could be fatal, but most overestimated the dose required. Most thought over twenty 500 mg (10 grams) tablets had to be taken for any adverse effect when, in fact, about 4 grams can be toxic.

Suggestions for reducing the risk:

Review dosing (based on age and weight) at well child visits.
Keep a single product for all children in the household and a consistent type of measuring device.
Improve product labeling to distinguish between concentrated drops and liquid suspension.
Instruct persons on the accepted dose: 10-15 mg/kg/dose every 4 to 6 hours, and no more than 5 doses in 24 hours. A six-hour interval is preferred if taken around the clock.
Educate caregivers to read labels and look for "acetaminophen," not brand names.
Discuss safe use of OTC medications with adolescents during routine visits and in Health classes. Include information about the additional risk of liver damage when ethanol and acetaminophen are combined.

McNeil's website www.tylenol.com and toll-free number 800-962-5357 offer easy reading materials.

(Burk M. Pediatric Pharmacotherapy 2000;6(3):1-4)

Comment: This is useful for school staff, parent and student education about safer use of a common medication. -J.O.






			Acetaminophen Safety This article reviewed acetaminophen toxicity and measures to prevent overdose. When excessive acetaminophen is taken, the normal metabolic pathways become saturated. The excess is metabolized through an alternative pathway (glutathione conjugation), but NAPQI (N-acetyl-p-benzoquinoneimine) accumulates and binds to liver cell proteins, causing cellular death. A single dose over 140 mg/Kg in children requires immediate treatment with N-acetylcysteine therapy to prevent hepatic failure. Little is known about chronic, lower dose toxicity. There are reported cases of children receiving adult doses despite clear product labels and of fatalities with doses less than 140 mg/Kg. In one study, only 30 of 100 parents could accurately calculate the dose. While 66% said they gave their children Tylenol¢ç, only 8% said they gave "acetaminophen." Caretakers do not realize multiple sources of the substance, thus risking cumulative doses when multiple medications are given. Viral illnesses, dehydration, and limited protein intake (from poor appetite) reduce the body's glutathione level and increase the degree of acetaminophen toxicity. Some medications, e.g., phenobarbital, phenytoin, rifampin, and isoniazid, affect liver enzyme function, increasing the level of toxic NAPQI. Lack of knowledge about acetaminophen toxicity can turn an adolescent suicide gesture into inadvertent death or liver damage. In a survey of American and British teens, over 90% knew that an overdose could be fatal, but most overestimated the dose required. Most thought over twenty 500 mg (10 grams) tablets had to be taken for any adverse effect when, in fact, about 4 grams can be toxic. Suggestions for reducing the risk: Review dosing (based on age and weight) at well child visits. Keep a single product for all children in the household and a consistent type of measuring device. Improve product labeling to distinguish between concentrated drops and liquid suspension. Instruct persons on the accepted dose: 10-15 mg/kg/dose every 4 to 6 hours, and no more than 5 doses in 24 hours. A six-hour interval is preferred if taken around the clock. Educate caregivers to read labels and look for "acetaminophen," not brand names. Discuss safe use of OTC medications with adolescents during routine visits and in Health classes. Include information about the additional risk of liver damage when ethanol and acetaminophen are combined. McNeil's website www.tylenol.com and toll-free number 800-962-5357 offer easy reading materials. (Burk M. Pediatric Pharmacotherapy 2000;6(3):1-4) Comment: This is useful for school staff, parent and student education about safer use of a common medication. -J.O.



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