PIPRACIL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PIPRACIL (PIPRACIL).
Piperacillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), interfering with peptidoglycan cross-linking during cell wall assembly.
| Metabolism | Piperacillin is partially metabolized by hydrolysis to desethyl piperacillin; primarily excreted unchanged in urine via glomerular filtration and tubular secretion. |
| Excretion | Primarily renal (tubular secretion and glomerular filtration) as unchanged drug (50-70%); biliary/fecal excretion is a minor route (approximately 10-20% as unchanged drug and metabolites). |
| Half-life | 0.7-1.2 hours in adults with normal renal function; prolonged to 3-6 hours in renal impairment (CrCl <20 mL/min). In neonates, half-life is 3-4 hours. |
| Protein binding | Approximately 16-21%, primarily to albumin. |
| Volume of Distribution | 0.2-0.3 L/kg (approx. 14-21 L in adults); indicates distribution primarily into extracellular fluid. |
| Bioavailability | IM: approximately 70-80% (based on comparison of AUC after IM vs IV administration). |
| Onset of Action | IV: Immediate; IM: 30-60 minutes (peak serum concentrations at 30-50 minutes after IM administration). |
| Duration of Action | 4-6 hours with normal renal function; dosing interval must be extended in renal impairment due to prolonged half-life. |
| Molecular Weight | 539.5 |
3.375 g IV every 6 hours (piperacillin 3 g + tazobactam 0.375 g) over 30 minutes; for nosocomial pneumonia: 4.5 g IV every 6 hours over 30 minutes.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 20-40 mL/min: 3.375 g IV every 8 hours; CrCl <20 mL/min: 2.25 g IV every 8 hours; hemodialysis: 2.25 g IV every 12 hours with additional 0.75 g post-dialysis. |
| Liver impairment | No dose adjustment required for hepatic impairment; piperacillin is primarily renally eliminated. |
| Pediatric use | For patients 2-9 months: 80 mg/kg piperacillin component IV every 8 hours; for >9 months: 100 mg/kg piperacillin component IV every 8 hours; max 4.5 g per dose. |
| Geriatric use | Start with lower end of dosing range due to age-related renal function decline; adjust based on CrCl; monitor renal function closely. |
| 1st trimester | Penicillins are generally considered safe in pregnancy; no known teratogenic effects reported. |
| 2nd trimester | Safe for use, no significant risks identified. |
| 3rd trimester | Safe for use; consider theoretical risk of altered gut flora in neonate if administered near delivery. |
Clinical note
Comprehensive clinical and safety monograph for PIPRACIL (PIPRACIL).
| Placental transfer | Crosses placenta and reaches fetal concentrations comparable to maternal serum. |
| Breastfeeding | Piperacillin is excreted into breast milk in low concentrations. Compatible with breastfeeding; however, monitor infant for potential gastrointestinal disturbances or allergic reactions. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to piperacillin or any penicillinHypersensitivity to beta-lactam antibiotics
| Precautions | Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported. Clostridium difficile-associated diarrhea (CDAD) may occur. Hemorrhagic manifestations have been associated with high doses; monitor coagulation parameters in patients with renal impairment. Neutropenia and agranulocytosis can occur with prolonged therapy. Do not use in patients with infectious mononucleosis due to high risk of skin rash. |
| Food/Dietary | No significant food interactions. However, high potassium intake should be monitored in patients with renal impairment due to risk of hyperkalemia. |
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| L1 - Safest |
| Teratogenic Risk | PIPRACIL is a penicillin antibiotic, classified as FDA Pregnancy Category B. No evidence of teratogenicity in animal studies. In humans, no adequate well-controlled studies in pregnant women; however, penicillins are generally considered safe during pregnancy. Fetal risk not established, but use only if clearly needed. No known risk in any trimester. |
| Fetal Monitoring | Monitor maternal renal function and CBC with differential periodically during prolonged therapy. No specific fetal monitoring required; standard prenatal care applies. |
| Fertility Effects | No known effects on fertility in animal studies or human data. No evidence of impaired fertility. |
| Clinical Pearls | PIPRACIL (piperacillin) is an extended-spectrum penicillin often used with tazobactam (Zosyn). Monitor for hypersensitivity reactions, especially in penicillin-allergic patients. Adjust dose in renal impairment (CrCl < 40 mL/min). Use with caution in patients with cystic fibrosis due to increased risk of drug fever and resistance. Consider extended infusion (over 3-4 hours) for resistant organisms. Can cause false-positive urine glucose tests with Clinitest but not with glucose oxidase methods. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Complete the full course of therapy to prevent resistance. · Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing) immediately. · Notify your doctor if you develop diarrhea, especially watery or bloody stools, as it may indicate Clostridium difficile infection. · Drink plenty of fluids unless otherwise instructed to prevent kidney stones. · Inform healthcare providers of all medications you are taking, including over-the-counter drugs and supplements. |