Ampicillin Dosage and Administration This insert is for a Pharmacy Bulk Package and is intended for preparing IV admixtures only. Dosage recommendations for intramuscular or direct intravenous injection are for informational purposes only. Infections of the respiratory tract and soft tissues. Patients weighing 40 kg (88 lbs) or more: 250 to 500 mg every 6 hours. Patients weighing less than 40 kg (88 lbs): 25 to 50 mg/kg/day in equally divided doses at 6- to 8- hour intervals. Infections of the gastrointestinal and genitourinary tracts (including those caused by Neisseria gonorrhoeae in females). Patients weighing 40 kg (88 lbs) or more: 500 mg every 6 hours. Patients weighing less than 40 kg (88 lbs): 50 mg/kg/day in equally divided doses at 6- to 8- hour intervals. In the treatment of chronic urinary tract and intestinal infections, frequent bacteriological and clinical appraisal is necessary. Smaller doses than those recommended above should not be used. Higher doses should be used for stubborn or severe infections. In stubborn infections, therapy may be required for several weeks. It may be necessary to continue clinical and/or bacteriological follow-up for several months after cessation of therapy. Urethritis in males due to N. gonorrhoeae. Adults – Two doses of 500 mg each at an interval of 8 to 12 hours. Treatment may be repeated if necessary or extended if required. In the treatment of complications of gonorrheal urethritis, such as prostatitis and epididymitis, prolonged and intensive therapy is recommended. Cases of gonorrhea with a suspected primary lesion of syphilis should have darkfield examinations before receiving treatment. In all other cases where concomitant syphilis is suspected, monthly serological tests should be made for a minimum of four months. The doses for the preceding infections may be given by either the intramuscular or intravenous route. A change to oral Ampicillin may be made when appropriate. Bacterial Meningitis Adults and children – 150 to 200 mg/kg/day in equally divided doses every 3 to 4 hours. (Treatment may be initiated with intravenous drip therapy and continued with intramuscular injections.) The doses for other infections may be given by either the intravenous or intramuscular route. Septicemia Adults and children – 150 to 200 mg/kg/day. Start with intravenous administration for at least three days and continue with the intramuscular route every 3 to 4 hours. Treatment of all infections should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained. A minimum of 10-days treatment is recommended for any infection caused by Group A beta-hemolytic streptococci to help prevent the occurrence of acute rheumatic fever or acute glomerulonephritis.

Ampicillin was tested in vitro for antibacterial activity against 673 clinical isolates of Gram-negative bacilli and Streptococcus faecalis. Taking the group of 673 isolates tested as a whole, 448 (67 %) were inhibited by ampicillin at a concentration of 5 ug/ml.