Imipenem

Class: Carbapenem antibiotic

Mechanism of Action: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), causing cell lysis. Broad spectrum against Gram-positive, Gram-negative, and anaerobic bacteria. Usually combined with cilastatin to prevent renal metabolism.

Indications

• Complicated intra-abdominal infections
• Complicated skin and soft tissue infections
• Severe hospital-acquired infections
• Complicated urinary tract infections
• Nosocomial and community-acquired pneumonia
• Febrile neutropenia (empiric therapy)
• Bone and joint infections

Dosage

• Adults: 500 mg–1 g IV every 6–8 hours (adjusted based on infection severity)
• Children (>3 months): 15–25 mg/kg IV every 6–8 hours
• Meningitis: 20–40 mg/kg IV every 8 hours in children

Maximum Dose

4 g/day (adults, depending on renal function)

Major Side Effects

• GI upset: nausea, vomiting, diarrhea
• Rash, hypersensitivity reactions
• Headache, dizziness
• Seizures (especially in CNS disease or renal impairment)
• Thrombophlebitis at injection site

Contraindications

• Hypersensitivity to imipenem, cilastatin, or other beta-lactams
• History of seizures (use with caution)

Compatible Fluids

• 0.9% Sodium Chloride
• 5% Dextrose

Route of Administration

• Intravenous (IV)
• Intramuscular (IM, less common)

Type of Administration

IV infusion over 20–60 minutes; IM deep injection for muscle administration.

Special Precautions

• Adjust dose in renal impairment (CrCl < 50 mL/min)
• Monitor for hypersensitivity reactions
• Use caution in patients with seizure disorders
• Concurrent use with valproate may reduce valproate levels
• Prolonged use may cause superinfection (e.g., C. difficile colitis)