Severe poisoning in a child caused by a small dose of clonidine

A girl aged 1 year 9 months ingested a single tablet of 0.3 mg of clonidine. She became soon drowsy and unconscious with bradycardia and severe hypotension. Bradycardia was antagonized promptly by atropine, and blood pressure was corrected by giving intravenous fluids. The level of consciousness fluctuated for 6 to 8 hr from alertness to unconsciousness. Serum concentrations of clonidine were only about two times higher than the mean therapeutic values in adults in the treatment of hypertension. Thus small doses of clonidine seem to be potentially dangerous for small children.