Imipenem/Cilastatin Kabi (Cilastatin Sodium, Imipenem Monohydrate)

Imipenem/Cilastatin is a carbapenem antibiotic used to treat infections caused by susceptible bacteria across several organ systems.

• Severe systemic infections: provides bactericidal activity against a broad spectrum of Gram‑negative and Gram‑positive pathogens.
• Intra‑abdominal infections: eradicates polymicrobial organisms involved in complicated abdominal sepsis.
• Urinary tract infections: clears resistant uropathogens in complicated UTIs.
• Skin and soft‑tissue infections: treats cellulitis and wound infections caused by susceptible bacteria.
• Pneumonia: effective against community‑acquired and hospital‑acquired bacterial pneumonia.
• Meningitis: penetrates the cerebrospinal fluid to treat bacterial meningitis.

• Imipenem binds to penicillin‑binding proteins, inhibiting the final stages of bacterial cell‑wall peptidoglycan synthesis, which leads to cell lysis. Cilastatin, co‑administered, inhibits renal dehydropeptidase I, preventing enzymatic degradation of imipenem and thereby maintaining therapeutic plasma concentrations.

Imipenem/Cilastatin may be associated with a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea
• Diarrhea
• Headache
• Infusion site phlebitis
• Rash
• Elevated liver enzymes

Serious or Rare Side Effects

• Seizures, especially in patients with renal impairment or CNS disorders
• Anaphylaxis or severe allergic reactions
• Clostridioides difficile‑associated colitis
• Thrombocytopenia or neutropenia
• Acute renal failure
• Hepatotoxicity

When prescribing Imipenem/Cilastatin, clinicians should consider several safety precautions to minimize risk.

• Renal function: assess and adjust dose in patients with impaired kidney function.
• Seizure risk: monitor patients with a history of seizures or CNS disorders.
• Allergy: avoid in individuals with known hypersensitivity to carbapenems or β‑lactam antibiotics.
• Pregnancy: use only if the potential benefit justifies the potential risk to the fetus.
• Drug interactions: review concomitant medications that may affect renal clearance or seizure threshold.
• Store at below 25°C: keep in the original packaging, protect from moisture and light.

Imipenem/Cilastatin can interact with other medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Valproic acid: concomitant use markedly reduces valproate plasma concentrations, risking loss of seizure control.
• CNS stimulants (e.g., phenobarbital, high‑dose carbamazepine): may increase the likelihood of seizures.

Moderate Interactions (Monitor Closely)

• Loop diuretics: may enhance renal clearance, necessitating dose adjustment.
• Aminoglycosides: combined use can increase nephrotoxicity.
• Warfarin: may alter INR, requiring closer coagulation monitoring.
• Oral contraceptives: carbapenems may reduce hormonal efficacy, advise alternative contraception.