Meropenem

# Meropenem ## Overview - **Classification**: Carbapenem antibiotic - **Mechanism**: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell lysis and death. ## Primary Indications 1. **Complicated Intra-abdominal Infections (cIAI)**: Including polymicrobial infections. 2. **Complicated Skin and Skin Structure Infections (cSSSI)**: Including cellulitis, abscesses. 3. **Bacterial Meningitis**: Due to susceptible bacteria. 4. **Hospital-Acquired Pneumonia (HAP) / Ventilator-Associated Pneumonia (VAP)**: For severe infections. 5. **Febrile Neutropenia**: As empirical therapy. ## Adult Dosing ### Standard Dosing **Complicated Intra-abdominal Infections (cIAI), Complicated Skin and Skin Structure Infections (cSSSI), Hospital-Acquired Pneumonia (HAP) / Ventilator-Associated Pneumonia (VAP), Febrile Neutropenia** - **Dose**: **1 g** - **Frequency**: Every 8 hours - **Route**: Intravenous (IV) infusion over 15-30 minutes or IV bolus over 3-5 minutes - **Duration**: 5-14 days, guided by clinical response. **Bacterial Meningitis** - **Dose**: **2 g** - **Frequency**: Every 8 hours - **Route**: IV infusion over 15-30 minutes - **Duration**: 7-21 days, depending on pathogen and site. ### Dose Adjustments - **Renal Impairment**: - CrCl 26-50 mL/min: **1 g** every 12 hours (Meningitis: **2 g** every 12 hours) - CrCl 10-25 mL/min: **500 mg** every 12 hours (Meningitis: **1 g** every 12 hours) - CrCl <10 mL/min: **500 mg** every 24 hours (Meningitis: **1 g** every 24 hours) - Hemodialysis: Administer dose after dialysis; **500 mg** every 24 hours (Meningitis: **1 g** every 24 hours) - **Hepatic Impairment**: No dose adjustment is generally needed. - **Elderly Patients**: Adjust dose based on renal function; no specific age-based adjustment otherwise. ## Pediatric Dosing ### Neonates (0-28 days) - **Indication**: Sepsis, meningitis, cIAI due to susceptible organisms. - **Dose (0-7 days)**: **20 mg/kg/dose** - **Frequency (0-7 days)**: Every 12 hours - **Dose (8-28 days)**: **20 mg/kg/dose** - **Frequency (8-28 days)**: Every 8 hours - **Maximum**: Consider **40 mg/kg/dose** for meningitis in specific cases, do not exceed **40 mg/kg/dose**. - **Special Notes**: Administer IV over 15-30 minutes. Monitor for seizures, especially in younger neonates. ### Infants (1-12 months) - **Indication**: cIAI, cSSSI, complicated UTI, meningitis, HAP. - **Dose (non-meningitis)**: **20 mg/kg/dose** - **Dose (meningitis)**: **40 mg/kg/dose** - **Frequency**: Every 8 hours - **Maximum**: **1 g/dose** (non-meningitis); **2 g/dose** (meningitis). - **Special Notes**: Administer IV over 15-30 minutes. ### Children (1-12 years) - **Indication**: cIAI, cSSSI, complicated UTI, meningitis, HAP, febrile neutropenia. - **Dose (non-meningitis)**: **10-20 mg/kg/dose** (varies by infection severity/site). - **Dose (meningitis)**: **40 mg/kg/dose** - **Frequency**: Every 8 hours - **Maximum**: **1 g/dose** (non-meningitis); **2 g/dose** (meningitis) or adult dose equivalent, whichever is less. - **Special Notes**: Administer IV over 15-30 minutes. ### Adolescents (13-18 years) - **Dose**: Generally follow **adult dosing guidelines** based on indication. - **Maximum**: **2 g/dose** (for meningitis) or **1 g/dose** (for other indications), not to exceed adult maximum daily dose. - **Special Notes**: Adjust for renal function if applicable. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to meropenem or other carbapenems. - **Absolute**: Severe hypersensitivity (e.g., anaphylaxis, severe skin reactions) to any beta-lactam antibiotic. ### Common Adverse Effects - **Very Common (>10%)**: Diarrhea, nausea/vomiting, rash, injection site reactions. - **Common (1-10%)**: Headache, constipation, anemia, thrombocytopenia, elevated liver enzymes (ALT, AST). - **Serious but Rare**: Seizures, C. difficile-associated diarrhea (CDAD), severe hypersensitivity reactions (anaphylaxis, SJS), neutropenia, agranulocytosis. ### Key Drug Interactions - **Valproic Acid/Divalproex**: Meropenem significantly reduces valproate levels, leading to loss of seizure control. Avoid concomitant use; consider alternative anticonvulsants. - **Probenecid**: Inhibits renal excretion of meropenem, increasing meropenem concentrations and half-life. Concomitant use is not recommended. - **Oral Anticoagulants (e.g., Warfarin)**: May enhance anticoagulant effect. Monitor INR closely, especially during co-administration. ## Monitoring & Follow-up - **Before Treatment**: Obtain cultures and susceptibility tests, assess baseline renal function (CrCl). - **During Treatment**: - **Clinical response**: Resolution of fever, improvement in infection signs/symptoms. - **Renal function**: Periodically, especially in patients with impaired renal function or on prolonged therapy. - **Hematology**: Complete blood count (CBC) for prolonged therapy. - **Liver function**: Liver function tests (LFTs) for prolonged therapy. - **Seizure activity**: Monitor in patients with CNS disorders or predisposing factors. - **Clinical Signs**: Monitor for development of rash, significant diarrhea (for CDAD), or new onset seizures. ## Clinical Pearls - 💡 **Tip 1**: Meropenem exhibits broad-spectrum activity against many Gram-positive, Gram-negative, and anaerobic bacteria. - 💡 **Tip 2**: For critically ill patients or those with resistant pathogens, consider extended infusions (e.g., over 3 hours) to optimize pharmacodynamic activity. - 💡 **Tip 3**: Always confirm a patient's allergy history, particularly to penicillins or other beta-lactams, before initiating meropenem. - 💡 **Tip 4**: Meropenem is NOT active against MRSA or VRE. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.