ampicillini

Ampicillin is an aminopenicillin antibiotic in the penicillin family. As a beta-lactam antibiotic, it inhibits the synthesis of bacterial cell walls by binding penicillin-binding proteins, leading to cell lysis. It is bactericidal and time-dependent in its action. It can be administered by mouth or by injection, and its pharmacokinetics vary with route and renal function.

Ampicillin has activity against many Gram-positive cocci such as Streptococcus species and Enterococcus faecalis, as well as several Gram-negative organisms including Escherichia coli, Haemophilus influenzae, and Proteus mirabilis; it is also active against Listeria monocytogenes. It does not reliably cover penicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa, and its usefulness is limited by beta-lactamase production in some bacteria. For broader coverage, it is commonly combined with a beta-lactamase inhibitor (for example ampicillin-sulbactam).

Pharmacokinetics: oral bioavailability is moderate, with lower peak levels than intravenous administration. It distributes into most body tissues and fluids, including cerebrospinal fluid when meninges are inflamed. The elimination half-life is about one hour in individuals with normal renal function; clearance is reduced in renal impairment and dosing must be adjusted accordingly.

Clinical use: ampicillin is used for a range of infections caused by susceptible organisms, such as certain respiratory tract infections, otitis media, meningitis due to Listeria, and urinary tract infections. For broader coverage or resistance issues, it is frequently combined with a beta-lactamase inhibitor to form ampicillin-sulbactam.

Safety: adverse effects include allergic reactions, rash, diarrhea, and occasional hypersensitivity. Cross-reactivity with other penicillins can occur. It may cause Clostridioides difficile-associated diarrhea. It is typically avoided in patients with a known penicillin allergy and doses may require adjustment in renal impairment.