NALLPEN IN PLASTIC CONTAINER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NALLPEN IN PLASTIC CONTAINER (NALLPEN IN PLASTIC CONTAINER).
Nallpen is a penicillinase-resistant penicillin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), specifically active against beta-lactamase-producing Staphylococcus aureus.
| Metabolism | Hepatic metabolism via hydrolysis to penicilloic acid; minor metabolism via other pathways. |
| Excretion | Primarily renal (60-80% unchanged drug via glomerular filtration and tubular secretion); biliary/fecal: minor (<5%) |
| Half-life | 0.9-1.2 hours; prolonged in renal impairment (up to 7-10 hours in anuria); requires dose adjustment for CrCl <30 mL/min |
| Protein binding | 45-65% bound primarily to albumin; low binding reduces risk of displacement interactions |
| Volume of Distribution | 0.3-0.4 L/kg; indicates distribution primarily into extracellular fluid; low tissue penetration |
| Bioavailability | IM: 70-85%; oral: not available (not orally bioavailable) |
| Onset of Action | IV: immediate (minutes); IM: 15-30 minutes |
| Duration of Action | IV: 4-6 hours; IM: 6-8 hours; short duration due to rapid renal clearance |
Nafcillin 1-2 g IV every 4 hours for moderate to severe infections; for MSSA bacteremia or endocarditis, 2 g IV every 4 hours.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for any degree of renal impairment. |
| Liver impairment | No specific dose adjustment recommended; use caution in severe hepatic impairment (Child-Pugh C) due to reduced clearance. |
| Pediatric use | Neonates: 25 mg/kg IV every 8-12 hours; Infants and children: 25-50 mg/kg IV every 6 hours; maximum 12 g/day. |
| Geriatric use | No specific dose adjustment; may consider lower end of dosing range due to age-related decline in renal function, but nafcillin is primarily hepatically eliminated. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NALLPEN IN PLASTIC CONTAINER (NALLPEN IN PLASTIC CONTAINER).
| Breastfeeding | Excretion into human milk unknown. M/P ratio not available. Caution advised; avoid breast-feeding during therapy due to potential for sedation or respiratory depression in the infant. |
| Teratogenic Risk | Nalfurafine is not recommended in pregnancy. There are no adequate human data; animal studies show fetal toxicity at high doses. First trimester: unknown risk; avoid. Second/third trimester: may cause neonatal withdrawal if used chronically near term. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to nafcillin or any penicillin","History of severe hypersensitivity reaction to any beta-lactam antibiotic"]
| Precautions | ["Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported","Clostridium difficile-associated diarrhea (CDAD) may occur","Use caution in patients with renal impairment (dosage adjustment may be needed)","Prolonged use may result in superinfection"] |
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| Monitor maternal vital signs, sedation level, and respiratory status. In late pregnancy, monitor fetal heart rate and uterine activity if used near term. Observe neonate for signs of opioid withdrawal (irritability, poor feeding) if maternal use close to delivery. |
| Fertility Effects | In animal studies, no impairment of fertility was observed. Human data lacking; theoretical risk of hormonal disruption with chronic use. |