Imipenem/Cilastatin Kabi (Cilastatin Sodium, Imipenem Monohydrate)

Imipenem/Cilastatin is a carbapenem antibiotic used to treat severe bacterial infections in various organ systems.

• Complicated intra‑abdominal infections: eradicates the causative pathogens, leading to resolution of infection and prevention of sepsis.
• Complicated urinary tract infections: eliminates Gram‑negative uropathogens, improving urinary symptoms and preventing renal complications.
• Skin and soft‑tissue infections: clears bacterial involvement in cellulitis, abscesses, and wound infections, promoting healing.
• Nosocomial pneumonia: treats hospital‑acquired lung infections caused by resistant organisms, supporting respiratory recovery.

• Imipenem exerts its antibacterial effect by binding to penicillin‑binding proteins (PBPs) on the bacterial cell wall, inhibiting the final transpeptidation step of peptidoglycan synthesis. This disruption weakens the cell wall, causing osmotic instability and bacterial lysis. Cilastatin is co‑administered to inhibit renal dehydropeptidase‑I, preventing rapid hydrolysis of imipenem and thereby increasing its plasma concentration and therapeutic efficacy.

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

Common Side Effects

• Nausea: mild gastrointestinal upset occurring in many patients.
• Diarrhea: loose stools that may be self‑limiting.
• Rash: skin erythema or pruritus.
• Injection site pain: discomfort at the intravenous site.
• Elevated liver enzymes: transient increase in hepatic transaminases.

Serious or Rare Side Effects

• Seizures: risk increased in patients with CNS disorders or renal impairment.
• Clostridioides difficile colitis: severe diarrhea due to intestinal flora disruption.
• Anaphylaxis: acute hypersensitivity reaction with respiratory and circulatory compromise.
• Renal toxicity: acute kidney injury especially with concomitant nephrotoxic drugs.

When using Imipenem/Cilastatin, clinicians should observe several safety measures to minimize risk.

• Renal function assessment: evaluate creatinine clearance before initiating therapy and adjust dose in impairment.
• Seizure risk: avoid in patients with a history of epilepsy or CNS disorders unless benefits outweigh risks.
• Hypersensitivity monitoring: discontinue immediately if signs of an allergic reaction appear.
• Concomitant valproic acid: avoid co‑administration as it can reduce valproate levels and precipitate seizures.
• Nephrotoxic drug caution: monitor closely when used with aminoglycosides or other nephrotoxic agents.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake the vial.

Imipenem/Cilastatin can interact with other medicines, influencing efficacy or safety.

Major Interactions (Avoid)

• Valproic acid: co‑administration markedly reduces valproate concentrations, increasing seizure risk.
• Other carbapenems: concurrent use may lead to additive toxicity without added benefit.

Moderate Interactions (Monitor Closely)

• Diuretics (e.g., furosemide): may enhance nephrotoxic potential; monitor renal function.
• Anticoagulants (e.g., warfarin): may alter INR; check coagulation parameters regularly.
• Oral contraceptives: antibiotics may reduce effectiveness; advise alternative contraception.