Ampicillin dosage and administration

Ampicillin
AMPICILLIN® FDA Package Insert
Description
Clinical Pharmacology
Microbiology
Indications and Usage
Contraindications
Warnings and Precautions
Adverse Reactions
Overdosage
Dosage and Administration
How Supplied
Labels and Packages

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mohamed Moubarak, M.D. [2]

Dosage and Administration

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.

Directions for Use

Use only freshly prepared solutions. Intramuscular and intravenous injections should be administered within one hour after preparation since the potency may decrease significantly after this period.

For Intramuscular Use

Dissolve contents of a vial with the amount of Sterile Water for Injection, USP, or Bacteriostatic Water for Injection, USP, listed in the table below:

While Ampicillin for Injection, USP, 1 gram and 2 grams, are primarily for intravenous use, they may be administered intramusculary when the 250 mg or 500 mg vials are unavailable. In such instances, dissolve in 3.5 or 6.8 mL Sterile Water for Injection, USP, or Bacteriostatic Water for Injection, USP, respectively. The resulting solution will provide a concentration of 250 mg per mL. Ampicillin for Injection, USP 125 mg, is intended primarily for pediatric use. It also serves as a convenient dosage form when small parenteral doses of the antibiotic are required.

For Direct Intravenous Use

Add 5 mL Sterile Water for Injection, USP, or Bacteriostatic Water for Injection, USP to the 250, and 500 mg vials and administer slowly over a 3- to 5- minute period. Ampicillin for Injection, USP, 1 gram or 2 grams, may also be given by direct Intravenous administration. Dissolve in 7.4 or 14.8 mL Sterile Water for Injection, USP, or Bacteriostatic Water for Injection, USP, respectively, and administer slowly over at least 10 to 15 minutes. CAUTION: More rapid administration may result in convulsive seizures.

For Administration by Intravenous Drip

Reconstitute as directed above ( For Direct Intravenous Use) prior to diluting with Intravenous Solution. Stability studies on ampicillin sodium at several concentrations in various intravenous solutions indicate the drug will lose less than 10% activitiy at the temperatures noted for the time periods stated.

Only those solutions listed above should be used for the intravenous infusion of Ampicillin for Injection, USP. The concentrations should fall within the range specified. The drug concentration and the rate and volume of the infusion should be adjusted so that the total dose of ampicillin is administered before the drug loses its stability in the solution in use.

References

Adapted from the FDA Package Insert.