Combined boric acid and cinchocaine chloride poisoning in a 12-month-old infant: evaluation of haemodialysis.

A mixture containing 3 g of boric acid and 300 mg of cinchocaine chloride prescribed due to painful dental protrusion was accidentally ingested by a 12-month-old girl. She developed violent vomiting and coughing. Irritability, tremor, seizures and a delirious reaction. She was treated with diazepam, intubated, sedated and ventilated. Her diuresis was stimulated with furosemide and fluid. Within the first 24 h she was treated with haemodialysis twice on femoral catheters. Her renal function was unaffected. In two days she fully recovered. The maximum measured levels of boric acid and cinchocaine chloride approximately 6 h after ingestion were 26 micrograms/ml and 71 ng/ml respectively. The plasma half-life of boric acid was 7.0 h and decreased to 3.6 and 4.4 h during the two haemodialyses. The total body clearance of boric acid increased correspondingly from 21 ml/min to 41 and 34 ml/min. The in vitro clearance of boric acid of the dialyser was later determined to be 18 ml/min. It is concluded that haemodialysis is valuable in the treatment of boric acid intoxication because it increases the elimination of the drug even in patients without any sign of renal toxicity.