Imipenem/Cilastatine Kabi (Cilastatin Sodium, Imipenem Monohydrate)

• Imipenem/cilastatin is a broad‑spectrum carbapenem antibiotic used for serious bacterial infections.
• Complicated intra‑abdominal infections: provides bactericidal activity against mixed aerobic and anaerobic pathogens.
• Complicated urinary tract infections: eradicates Gram‑negative and Gram‑positive organisms resistant to other agents.
• Skin and soft‑tissue infections: treats severe cellulitis and wound infections caused by susceptible bacteria.
• Nosocomial pneumonia: effective against hospital‑acquired respiratory pathogens.
• Febrile neutropenia: used empirically to cover likely bacterial causes in neutropenic patients.

• Imipenem binds to penicillin‑binding proteins, inhibiting the final stages of bacterial cell‑wall peptidoglycan synthesis, which leads to cell lysis. Cilastatin, a renal dehydropeptidase I inhibitor, prevents enzymatic degradation of imipenem in the kidneys, thereby maintaining therapeutic plasma concentrations and extending antibacterial activity.

Adverse reactions may occur with any antimicrobial therapy.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Diarrhea: may be self‑limiting or indicate altered gut flora.
• Rash: erythematous skin eruption, often transient.
• Injection site reactions: pain, erythema, or swelling at the infusion site.

Serious or Rare Side Effects

• Seizures: especially in patients with pre‑existing CNS disorders or high doses.
• Clostridioides difficile‑associated diarrhea: severe colitis requiring medical attention.
• Anaphylaxis: rapid onset of respiratory distress, hypotension, and urticaria.
• Stevens‑Johnson syndrome or toxic epidermal necrolysis: extensive skin detachment and mucosal involvement.

Careful assessment and monitoring are required before and during therapy.

• Renal function: adjust dosing in patients with impaired renal clearance.
• Seizure risk: monitor patients with a history of central nervous system disorders.
• Allergy: avoid in individuals with known hypersensitivity to carbapenems or β‑lactam antibiotics.
• Pregnancy: use only when the potential benefit justifies the potential risk to the fetus.
• Drug interactions: review concomitant medications that may lower the seizure threshold.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Imipenem/cilastatin may interact with several co‑administered drugs.

Major Interactions (Avoid)

• Valproic acid: may reduce plasma concentrations of valproate, risking loss of seizure control.
• Phenobarbital, phenytoin, carbamazepine: may increase the risk of seizures when combined.
• Renal dehydropeptidase inhibitors: can raise imipenem levels, increasing toxicity.

Moderate Interactions (Monitor Closely)

• Aminoglycosides: additive nephrotoxicity; monitor renal function.
• Loop diuretics: may enhance ototoxic risk when used with aminoglycosides.
• Proton pump inhibitors: minimal impact but should be reviewed for overall gastric pH effects.