n-acetylcysteine overdose after acetaminophen poisoning

N-acetylcysteine (nac) is a drug used widely and effectively in oral and intravenous forms as a specific antidote for acetaminophen poisoning. in children considering the toxic dose of acetaminophen ingested by the patient and the body weight, the physician prescribes a specific dose of nac. there is always a risk of iatrogenic overdose of nac which can cause different mild to severe temporary or permanent side effects, some of which can be life threatening. here we report a rare case of iatrogenic nac overdose following an error in calculation of the prescribed dose. the patient was a 2.5 years old boy that was brought to emergency room with overdose of acetaminophen syrup. the physician prescribed 2 grams of intravenous nac for him, but because of the miscalculation of the volume of the drug, the nurse infused about 20 grams of nac (10 times the prescribed dose) to the patient. immediately the patient became drowsy and developed decreased level of consciousness, stupor, repetitive intractable focal and generalized convulsions, decrease visual acuity and had prolonged hospitalization in intensive care unit and pediatric neurologic wards and perhaps will have permanent subtle intellectual and neurologic sequela. considering the possible errors in the prescription and administration of some critical and less commonly used drugs especially those which have several different formulary and also considering their possible serious and life threatening side effects, it is recommended that the dose and volume of such medications be calculated meticulously by at least two trained persons. also it is important to carry out the administration phases and check the patient’s symptoms more attentively and cautiously