Imipenem/Cilastatin Kabi (Cilastatin Sodium, Imipenem Monohydrate)

Imipenem/Cilastatin is a broad‑spectrum carbapenem antibiotic used for serious bacterial infections affecting various organ systems.

• Complicated intra‑abdominal infections: provides bactericidal activity against mixed aerobic and anaerobic pathogens.
• Complicated urinary tract infections: eradicates resistant Gram‑negative organisms causing pyelonephritis and cystitis.
• Skin and soft tissue infections: treats severe cellulitis and wound infections caused by susceptible bacteria.
• Nosocomial pneumonia: effective against hospital‑acquired lower respiratory tract infections, including ventilator‑associated pneumonia.
• Septicemia: used for systemic infections caused by susceptible strains when rapid bacterial clearance is required.

• Imipenem binds to penicillin‑binding proteins (PBPs) on bacterial cell walls, inhibiting the final transpeptidation step of peptidoglycan synthesis, which leads to cell lysis and death. Cilastatin is co‑administered to inhibit renal dehydropeptidase‑I, preventing rapid degradation of imipenem and thereby increasing its plasma concentration and antibacterial efficacy.

Adverse reactions may range from mild to severe and should be monitored during therapy.

Common Side Effects

• Nausea: mild gastrointestinal upset occurring in many patients.
• Diarrhea: may be watery and self‑limiting.
• Rash: skin erythema or pruritus.
• Elevated liver enzymes: transient increase in transaminases.
• Injection site reactions: pain, erythema, or swelling at the infusion site.
• Headache: occasional mild headache.

Serious or Rare Side Effects

• Seizures: risk increases with high doses or renal impairment.
• Clostridioides difficile‑associated diarrhea: may lead to colitis.
• Anaphylaxis: severe hypersensitivity reaction requiring immediate medical attention.
• Severe neutropenia: marked reduction in neutrophil count.
• Renal toxicity: worsening kidney function, especially with concomitant nephrotoxins.
• Hepatic failure: rare but potentially life‑threatening liver injury.

Careful assessment and monitoring are required before and during treatment.

• Renal function monitoring: adjust dose in patients with impaired renal clearance.
• Seizure risk: avoid in patients with a history of seizures or central nervous system disorders.
• Allergy assessment: confirm no known hypersensitivity to β‑lactam antibiotics.
• Concurrent nephrotoxic drugs: use with caution when combined with other renal‑toxic agents.
• Pregnancy and lactation: use only if benefits outweigh potential risks, as safety data are limited.
• Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze or shake.

Imipenem/Cilastatin may interact with several medicines; some require avoidance while others need close monitoring.

Major Interactions (Avoid)

• Valproic acid: may reduce serum levels, increasing seizure risk.
• Probenecid: can raise imipenem concentrations, leading to toxicity.
• CNS stimulants (e.g., phenobarbital): may lower seizure threshold.
• Cisplatin: additive nephrotoxicity.

Moderate Interactions (Monitor Closely)

• Loop diuretics: may increase risk of nephrotoxicity.
• Aminoglycosides: monitor renal function and drug levels.
• Warfarin: may alter INR; coagulation parameters should be checked regularly.