Ampicillin dosage in bacterial meningitis with special reference to Haemophilus influenzae

Ampicillin remains the preferred drug for most cases of bacterial meningitis, including those due to Haemophilus influenzae type b. A prospective study was performed comparing high (400 mg/kg per day)- and low (150 mg/kg per day)-dosage regimens of ampicillin in the treatment of 172 patients with bacterial meningitis. Response to both regimens was equivalent in terms of average hospital stay, duration of ampicillin therapy, microbiological response, and death and residua. Patients with H. influenzae infections treated with low-dosage regimens had slightly prolonged febrile courses. This study suggests that high-dosage regimens of ampicillin offer no benefit over low-dosage regimens in the treatment of bacterial meningitis.