When ampicillin became available for general use in 1964, it simplified treatment of bacterial meningitis during infancy and childhood. Those old enough to have lived through the "triple therapy" days will recall the many inconveniences and problems; the tremendous amount of nursing time involved in giving three different antimicrobials (and often lactate or bicarbonate for alkalinization of the urine) at four- or six-hourly intervals; repeatedly measuring sulfa levels in the blood (to assure that one was in the recommended range of 10 to 15 mg/100 ml), monitoring hematological and renal indices for drug toxicity; and the discomfort to the patient receiving all those injections. How they hated the subcutaneous injections of sulfadiazine and lactate in the belly!
Ampicillin changed all that. We had a single drug uniformly effective against the usual pathogens causing meningitis beyond the newborn period. It was well tolerated intravenously or intramuscularly, and serious drug toxicity did
Nelson JD. Should Ampicillin Be Abandoned for Treatment of Haemophilus influenzae Disease?. JAMA. 1974;229(3):322–324. doi:10.1001/jama.1974.03230410046026