Imipenem/Cilastatin Sun (Cilastatin, Imipenem)

Imipenem/cilastatin is a carbapenem antibiotic used to treat infections caused by susceptible bacteria.

• Complicated intra‑abdominal infections: provides broad‑spectrum coverage to resolve infection.
• Complicated urinary tract infections: eradicates uropathogens and improves clinical cure.
• Lower respiratory tract infections: treats pneumonia and bronchitis caused by resistant organisms.
• Skin and soft‑tissue infections: clears cellulitis, abscesses, and wound infections.
• Febrile neutropenia: offers empirical therapy for neutropenic patients with fever.

• Imipenem binds to penicillin‑binding proteins, inhibiting the final stages of bacterial cell‑wall peptidoglycan synthesis, which leads to cell lysis. Cilastatin, co‑administered, blocks renal dehydropeptidase I, preventing enzymatic degradation of imipenem and thereby increasing its plasma concentration and urinary excretion.

Common Side Effects

• Nausea: mild to moderate gastrointestinal upset.
• Diarrhea: may be watery and self‑limiting.
• Rash: erythematous skin eruption.
• Headache: transient cranial discomfort.
• Elevated liver enzymes: mild transaminase increase.
• Injection site pain: local discomfort during administration.

Serious or Rare Side Effects

• Seizures: especially in patients with CNS disorders or renal impairment.
• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Clostridioides difficile‑associated diarrhea: potentially life‑threatening colitis.
• Thrombophlebitis: inflammation of veins at the injection site.
• Renal toxicity: impaired kidney function in susceptible individuals.
• Severe hypersensitivity: including Stevens‑Johnson syndrome.

Imipenem/cilastatin should be used with caution and appropriate monitoring.

• Assess renal function: adjust dosing in patients with renal impairment.
• Monitor for seizures: increased risk in patients with CNS disorders.
• Evaluate for hypersensitivity: discontinue if allergic reaction occurs.
• Use caution in patients with a history of colitis: risk of C. difficile infection.
• Avoid concomitant use with valproic acid: may reduce valproate levels.
• Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Imipenem/cilastatin may interact with several medicines; clinical judgment is required.

Major Interactions (Avoid)

• Valproic acid: reduces serum valproate concentrations, risking seizure breakthrough.
• Probenecid: decreases renal clearance, increasing imipenem exposure.
• Other carbapenems: additive toxicity, avoid simultaneous use.

Moderate Interactions (Monitor Closely)

• Diuretics: may exacerbate electrolyte disturbances.
• NSAIDs: increase risk of renal impairment.
• Aminoglycosides: potential additive nephrotoxicity.
• Rifampin: may lower imipenem levels.
• Anticoagulants: monitor INR as interaction may alter anticoagulant effect.