PIPERACILLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PIPERACILLIN (PIPERACILLIN).
Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation, and activating autolytic enzymes.
| Metabolism | Partially metabolized via hydrolysis of the beta-lactam ring; minor hepatic metabolism. |
| Excretion | Renal: approximately 70-90% unchanged via glomerular filtration and tubular secretion; biliary: 10-20% excreted unchanged in bile; fecal: minor (<5%) |
| Half-life | 0.6-1.2 hours in adults with normal renal function; prolonged to 2-6 hours in renal impairment (CrCl <20 mL/min); requires dose adjustment in renal failure |
| Protein binding | 20-30% bound to serum proteins (primarily albumin) |
| Volume of Distribution | 0.18-0.3 L/kg; distributes into interstitial fluid, bile, tissues; low penetration into CSF unless meninges inflamed |
| Bioavailability | IM: 70-80%; oral: negligible (not administered orally; IV/IM only) |
| Onset of Action | IV: immediately (within minutes); IM: 15-30 minutes |
| Duration of Action | 4-6 hours in normal renal function; extended in renal impairment; typically dosed every 4-6 hours due to short half-life |
| Molecular Weight | 517.5 |
3.375 g IV every 6 hours (piperacillin-tazobactam); for piperacillin alone, 3 g IV every 6 hours.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl >40 mL/min: no adjustment. 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 an additional dose after dialysis. |
| Liver impairment | No dose adjustment required for hepatic impairment; piperacillin is minimally hepatically metabolized. |
| Pediatric use | For piperacillin-tazobactam: Infants and children <40 kg: 100 mg piperacillin component per kg IV every 8 hours (neonates <2 kg and <7 days: 100 mg/kg every 12 hours). |
| Geriatric use | No specific geriatric dose; adjust based on renal function due to age-related decline in CrCl. |
| 1st trimester | Piperacillin crosses the placenta. Animal studies show no evidence of fetal harm. Limited human data; considered safe if clinically indicated. |
| 2nd trimester | No known teratogenic effects. Use during second trimester is considered low risk. |
| 3rd trimester | Generally considered safe; may be used for maternal infections. Caution near term due to potential for neonatal diarrhea or sensitization. |
Clinical note
Comprehensive clinical and safety monograph for PIPERACILLIN (PIPERACILLIN).
| Placental transfer | Piperacillin crosses the placenta freely, achieving therapeutic concentrations in fetal serum and amniotic fluid. |
| Breastfeeding | Piperacillin is excreted into breast milk in low concentrations. The American Academy of Pediatrics considers it compatible with breastfeeding. No adverse effects reported in nursing infants. Use caution in infants with known penicillin allergy. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to piperacillin or any penicillinHypersensitivity to cephalosporins (cross-sensitivity)
| Precautions | Hypersensitivity reactions (including anaphylaxis) in patients with beta-lactam allergy, Clostridioides difficile-associated diarrhea, Renal impairment: dosage adjustment required, Hematologic effects (leukopenia, neutropenia, thrombocytopenia) with prolonged therapy, Electrolyte disturbances (hypokalemia) with high doses due to sodium content |
| Food/Dietary | No significant food interactions. Administer without regard to meals. However, for patients with chronic kidney disease, dietary sodium and potassium intake may need monitoring due to sodium content in the formulation. |
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| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Piperacillin is classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate human studies in pregnant women exist. First trimester: No known teratogenic effects. Second/Third trimesters: No known fetal harm; use only if clearly needed. |
| Fetal Monitoring | Monitor renal function (serum creatinine, BUN), liver function tests, CBC with differential, and signs of hypersensitivity or superinfection. Fetal monitoring not specifically required unless maternal infection compromises pregnancy. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies show no impairment of fertility at therapeutic doses. |
| Clinical Pearls | Piperacillin is a ureidopenicillin with activity against Pseudomonas aeruginosa. It is often combined with tazobactam (a beta-lactamase inhibitor) to extend coverage against beta-lactamase-producing organisms. Dosing must be adjusted in renal impairment (creatinine clearance <20 mL/min). It is compatible with aminoglycosides but should not be mixed in the same IV line. Monitor for hypersensitivity reactions, including rash and anaphylaxis, especially in patients with penicillin allergy. |
| Patient Advice | Take this medication exactly as prescribed; do not skip doses. · Complete the full course of therapy even if you feel better. · Inform your doctor if you have a history of allergies, especially to penicillins or cephalosporins. · Report any signs of an allergic reaction (rash, itching, swelling, difficulty breathing) immediately. · This medication may cause diarrhea; notify your doctor if it becomes severe or bloody. · If you are taking oral contraceptives, use an additional non-hormonal method of birth control during treatment. |