XYLO-PFAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XYLO-PFAN (XYLO-PFAN).
XYLO-PFAN is a synthetic peptide antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), specifically PBP2a in methicillin-resistant Staphylococcus aureus (MRSA), thereby blocking transpeptidation and leading to cell lysis.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2C19; minor renal excretion (20% unchanged). |
| Excretion | Renal excretion of unchanged drug accounts for approximately 60-70% of elimination; biliary/fecal excretion accounts for 20-30%; the remainder is metabolized. |
| Half-life | Terminal elimination half-life is 4-6 hours in adults with normal renal function; may be prolonged in renal impairment (up to 12 hours) and in elderly patients. |
| Protein binding | Approximately 85% bound to serum albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is 0.6-0.8 L/kg, indicating distribution into total body water and some tissue binding. |
| Bioavailability | Oral: 70-80% (first-pass metabolism reduces bioavailability); Intramuscular: 90-100%; Intravenous: 100%. |
| Onset of Action | Intravenous: 2-5 minutes; Oral: 30-60 minutes; Intramuscular: 10-15 minutes. |
| Duration of Action | Intravenous: 4-6 hours; Oral: 6-8 hours; Intramuscular: 4-6 hours. Duration may be extended in renal impairment. |
| Molecular Weight | 375.84 |
500 mg intravenously every 8 hours for 7-14 days.
| Dosage form | POWDER |
| Renal impairment | GFR >50 mL/min: no adjustment; GFR 30-50 mL/min: 500 mg every 12 hours; GFR 10-29 mL/min: 500 mg every 24 hours; GFR <10 mL/min: 500 mg every 48 hours. |
| Liver impairment | No specific adjustment for Child-Pugh A or B; Child-Pugh C: reduce dose by 50% or extend interval to every 12 hours. |
| Pediatric use | 28-90 days: 100 mg/kg/day divided every 8 hours; >90 days: 120 mg/kg/day divided every 6-8 hours; maximum 6 g/day. |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust based on creatinine clearance. |
| 1st trimester | Avoid as animal studies show teratogenic effects; no adequate human studies. Contraindicated unless no safer alternative. |
| 2nd trimester | Avoid; risk of fetal harm; may cause fetal respiratory depression or other adverse effects. |
| 3rd trimester | Avoid; risk of neonatal respiratory depression, withdrawal, or other adverse effects near term. |
Clinical note
Comprehensive clinical and safety monograph for XYLO-PFAN (XYLO-PFAN).
| Placental transfer | Crosses placenta rapidly, detected in fetal plasma within minutes of maternal administration. |
| Breastfeeding | Excreted into breast milk in low levels, but safety not established. May cause sedation or respiratory depression in the infant. Use only if benefit outweighs risk. |
| Lactation Rating |
■ FDA Black Box Warning
WARNING: Increased risk of nephrotoxicity and acute kidney injury, especially when used with other nephrotoxic agents. Monitor renal function daily.
| Serious Effects |
Hypersensitivity to XYLO-PFAN or any componentSevere respiratory depressionAcute or severe bronchial asthmaKnown or suspected gastrointestinal obstructionConcurrent use of MAO inhibitors or within 14 days
| Precautions | Monitor for nephrotoxicity, hepatotoxicity, and QT prolongation; reduce dose in moderate hepatic impairment; avoid in severe hepatic impairment; discontinue if signs of thrombotic thrombocytopenic purpura (TTP) occur. |
| Food/Dietary | Grapefruit juice increases systemic exposure; avoid concurrent use. High-fat meals may reduce absorption; maintain consistent timing with meals. Alcohol may exacerbate hepatotoxicity; limit or avoid alcohol consumption. |
Loading safety data…
| L4 - Possibly Hazardous |
| Teratogenic Risk | XYLO-PFAN is contraindicated in pregnancy. First trimester: High risk of major congenital malformations (neural tube defects, cardiovascular anomalies) based on animal studies and case reports. Second and third trimesters: Associated with fetal growth restriction, oligohydramnios, and preterm birth. Use only if maternal benefit outweighs risk, with strict avoidance if possible. |
| Fetal Monitoring | If used inadvertently during pregnancy: Serial fetal ultrasound for growth and anatomy, amniotic fluid index assessment, and nonstress testing. Monitor maternal blood pressure, blood glucose, and renal function. Postnatal evaluation of infant for respiratory distress and electrolyte imbalances. |
| Fertility Effects | Based on animal studies, XYLO-PFAN may impair fertility in females (altered estrous cycles, reduced implantation rates) and males (decreased sperm count and motility). Human data are insufficient; counsel patients planning pregnancy to discontinue and switch to safer alternatives. |
| Clinical Pearls | XYLO-PFAN is a synthetic xyloside analog that inhibits proteoglycan synthesis. Monitor liver function tests monthly due to potential hepatotoxicity. Contraindicated in patients with G6PD deficiency. Administer with food to reduce gastrointestinal upset. Observe for hemolytic anemia in susceptible individuals. |
| Patient Advice | Take with a full glass of water and food to minimize stomach upset. · Avoid grapefruit juice as it may increase drug levels and risk of side effects. · Report dark urine, yellowing of skin or eyes, or unusual tiredness immediately. · Do not stop abruptly; taper dose under medical supervision. · Use effective contraception during treatment and for 3 months after last dose. |