Piperacillin

# Piperacillin ## Overview - **Drug Discussed**: Piperacillin, typically administered as the combination product **Piperacillin/Tazobactam** due to enhanced spectrum and resistance protection. Information below refers to the combination (e.g., Zosyn). - **Classification**: Extended-spectrum penicillin, beta-lactam antibiotic. Tazobactam is a beta-lactamase inhibitor. - **Mechanism**: Piperacillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). Tazobactam inactivates beta-lactamases, protecting piperacillin from degradation. ## Primary Indications 1. **Complicated Intra-abdominal Infections** - Including appendicitis, peritonitis. 2. **Nosocomial Pneumonia** - Including ventilator-associated pneumonia (VAP). 3. **Complicated Skin & Skin Structure Infections** - Including diabetic foot infections. 4. **Gynecological Infections** - E.g., endometritis, pelvic inflammatory disease. 5. **Bacteremia** - Associated with specified infections or febrile neutropenia. 6. **Febrile Neutropenia** - Empiric therapy for presumed bacterial infection. ## Adult Dosing ### Standard Dosing **Most Indications (e.g., Nosocomial Pneumonia, Intra-abdominal, Skin/Soft Tissue)** - **Dose**: **3.375 g** (Piperacillin 3 g/Tazobactam 0.375 g) - **Frequency**: Every **6 hours** (Q6H) - **Route**: Intravenous (IV) infusion over 30 minutes, or extended infusion over 3-4 hours. - **Duration**: Typically 5-14 days, depending on infection severity. **Febrile Neutropenia** - **Dose**: **4.5 g** (Piperacillin 4 g/Tazobactam 0.5 g) - **Frequency**: Every **6 hours** (Q6H) - **Route**: IV infusion over 30 minutes, or extended infusion over 3-4 hours. - **Duration**: Until resolution of fever and neutropenia, or pathogen-directed. ### Dose Adjustments - **Renal Impairment**: Adjust based on CrCl. - CrCl 20-40 mL/min: **2.25 g** IV Q6H or **3.375 g** IV Q8H. - CrCl <20 mL/min: **2.25 g** IV Q8H or **3.375 g** IV Q12H. - Hemodialysis (HD): **2.25 g** IV Q8H; administer **0.75 g** post-dialysis supplement dose. - CRRT/CVVH: May require standard doses; monitor drug levels. - **Hepatic Impairment**: No specific dose adjustment generally needed. Monitor for adverse effects. - **Elderly Patients**: Adjust based on renal function; often have reduced CrCl. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **75-100 mg/kg** (piperacillin component) - **Frequency**: Q8-12H (highly variable, dependent on age/gestational age). - **Maximum**: **Not well-established** in neonates; use with caution. - **Special Notes**: Use with extreme caution. Renal elimination is immature. Consult infectious disease specialist. ### Infants (1-12 months) - **Dose**: **80 mg/kg** (piperacillin component) - **Frequency**: Every **6 hours** (Q6H) - **Maximum**: **4.5 g/dose** (Piperacillin 4g/Tazobactam 0.5g). - **Special Notes**: Adjust for renal impairment if present. ### Children (1-12 years) - **Most Indications**: - **Dose**: **80 mg/kg** (piperacillin component) - **Frequency**: Every **6 hours** (Q6H) - **Maximum**: **4.5 g/dose** (Piperacillin 4g/Tazobactam 0.5g). - **Cystic Fibrosis (higher doses)**: - **Dose**: **100-112.5 mg/kg** (piperacillin component) - **Frequency**: Every **6 hours** (Q6H) - **Maximum**: **4.5 g/dose** (Piperacillin 4g/Tazobactam 0.5g). - **Special Notes**: Total daily dose should not exceed adult maximums. ### Adolescents (13-18 years) - **Dose**: Generally follows **adult dosing** guidelines. - **Maximum**: **4.5 g** Q6H. ## Safety Information ### Contraindications - **Absolute**: History of severe hypersensitivity to piperacillin, tazobactam, other penicillins, or beta-lactamase inhibitors. - **Absolute**: History of severe hypersensitivity to cephalosporins (potential cross-reactivity). ### Common Adverse Effects - **Very Common (>10%)**: Diarrhea, Nausea, Headache. - **Common (1-10%)**: Rash, Vomiting, Constipation, Insomnia, Fever, Hypokalemia. - **Serious but Rare**: Anaphylaxis, Clostridioides difficile infection (CDI), Seizures, Leukopenia, Thrombocytopenia, Nephrotoxicity, Neurotoxicity, Stevens-Johnson syndrome. ### Key Drug Interactions - **Methotrexate**: May decrease methotrexate clearance, increasing toxicity. **Monitor methotrexate levels; consider dose adjustment or alternative.** - **Aminoglycosides (e.g., Gentamicin)**: Inactivation can occur *in vitro*. Administer separately and flush line. **Monitor aminoglycoside levels if co-administered.** - **Oral Anticoagulants (e.g., Warfarin)**: May alter coagulation parameters. **Monitor INR/PT closely; adjust anticoagulant dose.** - **Vecuronium**: Prolongs neuromuscular blockade. **Monitor for prolonged paralysis; use with caution.** - **Probenecid**: Decreases renal tubular secretion, increasing piperacillin/tazobactam levels. **No dose adjustment generally needed, but monitor for increased effects.** ## Monitoring & Follow-up - **Before Treatment**: Culture & sensitivity (if applicable), renal function (SCr, CrCl), liver function (ALT/AST), CBC. - **During Treatment**: - **Renal function**: Daily to every other day, especially in critically ill. - **CBC**: Periodically for prolonged therapy (>10 days) due to neutropenia/thrombocytopenia risk. - **Electrolytes**: Especially potassium, due to hypokalemia risk. - **Clinical response**: Resolution of fever, improved signs/symptoms of infection. - **Clinical Signs**: Monitor for rash, severe diarrhea, allergic reactions, signs of superinfection. ## Clinical Pearls - 💡 **Extended Infusion**: Administering over 3-4 hours (vs. 30 min) is often preferred for optimal pharmacodynamics and may improve outcomes in critical illness. - 💡 **Electrolyte Imbalance**: High doses can lead to hypokalemia. Monitor serum potassium and replete as needed. - 💡 **Nephrotoxicity**: Concomitant use with vancomycin may increase risk of acute kidney injury (AKI). Monitor renal function closely. - 💡 **Allergy Assessment**: Always thoroughly assess penicillin allergy history. Distinguish true IgE-mediated reactions from non-allergic events. - 💡 **C. difficile Risk**: Like all broad-spectrum antibiotics, carries a risk of C. difficile infection (CDI). Monitor for new-onset diarrhea. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.