Diagnosis, treatment, and follow-up of neonatal mepivacaine intoxication secondary to paracervical and pudendal blocks during labor.

Seven infants developed mepivacaine intoxication secondary to accidental injection during paracervical or pudental blocks or both. All presented with unexplained neonatal depression at birth, tonic seizures (often with apnea) within six hours, and characteristic neurologic findings. Twenty-four-hour urinary excretion produced 12.7 to 37.4 mg, exchange transfusions less than 1.02 to 3.5 mg, and gastric drainage or lavage or both 0.63 to 1.26 mg of mepivacaine. Thus promotion of urinary excretion is the treatment of choice. All six survivors are seizure free and neurologically and developmentally normal at one to 4 1/2 years. With early diagnosis and prevention of severe perinatal hypoxia, the prognosis from intoxication alone is very good.