ampisilliini

Ampisilliini, known in English as ampicillin, is a semisynthetic beta-lactam antibiotic in the penicillin class. It is an aminopenicillin that inhibits bacterial cell wall synthesis by binding to penicillin‑binding proteins, rendering it bactericidal against susceptible organisms.

The spectrum includes many Gram-positive cocci such as Streptococcus species and Enterococcus faecalis, and several Gram-negative bacteria such as Escherichia coli, Haemophilus influenzae, Salmonella and Shigella. It is notably active against Listeria monocytogenes. Ampicillin is less effective against beta-lactamase–producing organisms and is not active against most methicillin-resistant Staphylococcus aureus or many anaerobes unless combined with a beta-lactamase inhibitor.

Ampicillin is available in oral form and by injection (intravenous or intramuscular). Oral absorption can be reduced by food. It distributes broadly in body fluids and penetrates the cerebrospinal fluid when meninges are inflamed. It is primarily excreted by the kidneys and has a relatively short half-life, often requiring dose adjustment in renal impairment.

Clinical uses include infections caused by susceptible organisms, such as certain pneumonias, otitis and sinusitis, urinary tract infections, and meningitis due to Listeria or other susceptible pathogens. It is also employed for selected gynecologic and intra‑abdominal infections. To broaden coverage and overcome resistance, ampicillin is commonly combined with a beta-lactamase inhibitor (for example, ampicillin–sulbactam).

Adverse effects are typically mild but can include rash, diarrhea, and hypersensitivity reactions. A rash may occur with concomitant allopurinol use or in infectious mononucleosis. Less common risks include superinfections and, at high doses, seizures.