Cefotaxime

BRAND NAMES

• Claforan

• Cefotax

• Cefotaxime-Sandoz

• Frixim

• Cefotaxim

MECHANISM OF ACTION 

Cefotaxime works by inhibiting bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) on the bacterial cell membrane, which are enzymes essential for cross-linking the peptidoglycan layer of the cell wall. By blocking this process, cefotaxime prevents the bacteria from forming a stable cell wall, causing cell lysis and death. This makes it bactericidal, meaning it kills bacteria rather than just stopping their growth.

PHARMACOKINETICS

Absorption

Cefotaxime is not absorbed orally and must be given intravenously (IV) or intramuscularly (IM). After administration, it is rapidly distributed in body fluids and tissues, including the lungs, bile, bones, and cerebrospinal fluid (especially when meninges are inflamed).

Distribution

Cefotaxime is widely distributed in body tissues and fluids, including the lungs, liver, kidneys, bones, bile, and cerebrospinal fluid (especially if meninges are inflamed). It binds moderately to plasma proteins (about 30–50%) and penetrates well into most tissues, making it effective for treating systemic and severe infections.

Metabolism

Cefotaxime is partially metabolized in the liver to an active desacetyl metabolite, which also has antibacterial activity. About 15–30% of the drug is converted this way, while the rest remains unchanged and is eventually excreted by the kidneys. This metabolism contributes to its overall effectiveness against infections.

Excretion

Cefotaxime is primarily excreted by the kidneys through urine, both as unchanged drug and as its active desacetyl metabolite. A smaller amount is eliminated via bile. Its half-life is about 1 hour in patients with normal kidney function, and dosage adjustments are needed in renal impairment to prevent accumulation.

PHARMACODYNAMICS

Cefotaxime is a time-dependent, bactericidal antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins, causing cell lysis. It is most active against gram-negative bacteria, and its effectiveness depends on maintaining drug levels above the MIC during the dosing interval.

ADIMINISTRATION

Cefotaxime is given parenterally via intravenous (IV) injection or infusion or intramuscular (IM) injection when IV access is not available. Adult doses are usually 1–2 g every 8–12hours, while children receive 50–180 mg/kg/day divided doses. Dose adjustments are needed in renal impairment to maintain effectiveness and safety.

DOSAGE AND STRENGTH

Cefotaxime is administered parenterally, either intravenously (IV) by slow injection or infusion, or intramuscularly (IM) when IV access is not available. The usual adult dose is 1–2 g every 8–12 hours, with a maximum of 12 g per day, while childrentypically receive 50–180 mg/kg/day divided into 2–4 doses. Renal impairment requires dose adjustment to ensure safe and effective therapy.

FOOD INTERACTIONS

Cefotaxime has no significant food interactions. It is usually given as an injection (IV or IM), so food doesn’t directly affect how it works.

CONTRAINDICATIONS

• Known hypersensitivity to cefotaxime, other cephalosporins or β-lactam antibiotics. 

• History of serious allergic reactions (e.g. anaphylaxis) to penicillin, due to potential cross-reactivity. 

• Neonates with hyperbilirubinemia who require IV solutions containing calcium because precipitation may occur.

SIDE EFFECTS

• Diarrhea

• Nausea or vomiting

• Skin rash

• Fever

• Allergic reactions (itching, hives)

• Changes in blood counts (low WBC or platelets)

• Increased liver enzymes

• Severe allergic reaction (rare)

• Severe diarrhea (antibiotic-associated colitis)

• Unusual bleeding or bruising

• Seizures (rare)

OVER DOSE

• Nausea, vomiting, diarrhea, dizziness

• Rarely, confusion or seizures

TOXICITY