PYOPEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PYOPEN (PYOPEN).
Carbenicillin is a bactericidal penicillin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), disrupting peptidoglycan cross-linking.
| Metabolism | Carbenicillin is partially metabolized by hydrolysis of the beta-lactam ring; major metabolite is penicilloic acid. It is also excreted unchanged in urine via renal tubular secretion. |
| Excretion | Primarily renal (60-90% unchanged via glomerular filtration and tubular secretion); small amounts biliary (10-30%) and fecal (<10%). |
| Half-life | 30-60 minutes in normal renal function; prolonged to 2-4 hours in moderate renal impairment (CrCl 10-30 mL/min) and up to 10 hours in severe renal failure. |
| Protein binding | 16-20% bound to serum albumin. |
| Volume of Distribution | 0.2-0.3 L/kg; indicates distribution primarily in extracellular fluid. |
| Bioavailability | IM: 70-85%; oral: not available (acid-labile). |
| Onset of Action | IV: immediate; IM: 15-30 minutes. |
| Duration of Action | IV: 2-4 hours; IM: 4-6 hours. Duration may be extended in renal impairment. |
4 g intravenously every 4 hours.
| Dosage form | INJECTABLE |
| Renal impairment | For CrCl 10-50 mL/min: 4 g every 8 hours; for CrCl <10 mL/min: 4 g every 12 hours. |
| Liver impairment | No adjustment required for hepatic impairment. |
| Pediatric use | 200-400 mg/kg/day intravenously divided every 4-6 hours. |
| Geriatric use | Adjust based on renal function; start at lower end of dosing range. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PYOPEN (PYOPEN).
| Breastfeeding | Carbenicillin is excreted into breast milk in low concentrations (M/P ratio approximately 0.01-0.03). The amount ingested by a nursing infant is unlikely to cause adverse effects. However, theoretical risks include alteration of infant gut flora and sensitization. Use with caution in breastfeeding women. |
| Teratogenic Risk | Pyopen (carbenicillin) is a penicillin-class antibiotic classified as FDA Pregnancy Category B. Animal reproduction studies have not demonstrated fetal risk, and there are no adequate and well-controlled studies in pregnant women. Use during pregnancy should only be if clearly needed. No specific teratogenic effects have been reported in the first trimester. In later trimesters, high doses may theoretically alter gut flora, but no direct fetal harm is documented. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Hypersensitivity to penicillins","History of cephalosporin anaphylaxis"]
| Precautions | ["Hypersensitivity reactions including anaphylaxis","Renal impairment requires dose adjustment","Monitor electrolytes due to high sodium content","Superinfection with resistant organisms","Bleeding abnormalities associated with high doses","Neurologic reactions with high doses in renal failure"] |
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| Fetal Monitoring | Monitor for maternal allergic reactions, including anaphylaxis, rash, and diarrhea. In pregnancy, assess for signs of maternal infection and response to therapy. Fetal monitoring as per standard obstetric practice; no specific fetal monitoring required for carbenicillin use. |
| Fertility Effects | No known effects on fertility. Animal studies have not reported reproductive impairment at therapeutic doses. There is no evidence of adverse impact on spermatogenesis or oogenesis. |