Ampicillin

What it is and how it works

Mechanism of Action Ampicillin is similar to penicillin in its bactericidal action against susceptible bacteria during the stage of active multiplication. It acts through the inhibition of cell wall biosynthesis that leads to the death of the bacteria.

Indications

INDICATIONS AND USAGE To reduce the development of drug-resistant bacteria and maintain the effectiveness of ampicillin capsules, ampicillin for oral suspension and other antibacterial drugs, ampicillin capsules and ampicillin for oral suspension should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria. When culture and susceptibility information are available, they should be considered in selecting of modifying antimicrobial therapy, in the absence of such data, local epidemiology and susceptibility patterns contribute to the empiric selection of therapy. Ampicillin capsules and ampicillin for oral suspension are indicated in the treatment of infections caused by susceptible strains of the designated organisms listed below: Infections of the genitourinary tract including gonorrhea: E. coli, P. mirabilis, enterococci , Shigella, S. typhosa and other Salmonella , and nonpenicillinase producing N. gonorrhoeae . Infections of the respiratory tract: Nonpenicillinase- producing H.

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION Adults and children weighing over 20 kg: For genitourinary or gastrointestinal tract infections other than gonorrhea in men and women, the usual dose is 500 mg qid in equally spaced doses; severe or chronic infections may require larger doses. For the treatment of gonorrhea in both men and women, a single oral dose of 3.5 grams of ampicillin administered simultaneously with 1 gram of probenecid is recommended. Physicians are cautioned to use no less than the above recommended dosage for the treatment of gonorrhea. Follow-up cultures should be obtained from the original site(s) of infection 7 to 14 days after therapy.

Contraindications

CONTRAINDICATIONS The use of Ampicillin is contraindicated in individuals with a history of serious hypersensitivity reactions (e.g., anaphylaxis or Stevens-Johnson syndrome) to ampicillin or to other beta-lactam antibacterial drugs. Ampicillin is also contraindicated in infections caused by penicillinase-producing organisms. Ampicillin is contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with treatment with ampicillin.

Warnings and precautions

WARNINGS SERIOUS AND OCCASIONALLY FATAL HYPERSENSITIVITY (ANAPHYLACTIC) REACTIONS HAVE BEEN REPORTED IN PATIENTS ON PENICILLIN THERAPY. ALTHOUGH ANAPHYLAXIS IS MORE FREQUENT FOLLOWING PARENTERAL THERAPY, IT HAS OCCURRED IN PATIENTS ON ORAL PENICILLINS. THESE REACTIONS ARE MORE LIKELY TO OCCUR IN INDIVIDUALS WITH A HISTORY OF SENSITIVITY TO MULTIPLE ALLERGENS. THERE HAVE BEEN REPORTS OF INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY WHO HAVE EXPERIENCED SEVERE REACTIONS WHEN TREATED WITH CEPHALOSPORINS.

Pregnancy

Pregnancy Teratogenic Effects Reproduction studies in animals have revealed no evidence of impaired fertility or harm to the fetus due to penicillin. There are, however, no adequate and well-controlled studies in pregnant women.

Storage and supply

Store at 20°C to 25°C (68°F to 77°F) . Dispense in a tight container. Clinitest ® is a registered trademark of Miles, Inc. Clinistix ® is a registered trademark of Bayer Corporation. Tes-Tape ® is a registered trademark of Eli Lilly Company. Revised: 07/2025 Manufactured by Sandoz GmbH., Austria for Sandoz Inc., Princeton, NJ 08540

Source: Ampicillin (Ampicillin) — US FDA prescribing information, 2025-07-17, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.