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 |
| Molecular Weight | 436.45 |
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 | Animal studies have shown embryotoxicity; no adequate human studies. Avoid in first trimester unless maternal benefit justifies risk. |
| 2nd trimester | No adequate human studies; potential risk of fetal nephrotoxicity and ototoxicity. Use only if clearly needed. |
| 3rd trimester | Risk of fetal nephrotoxicity, ototoxicity, and neuromuscular blockade. Avoid use during labor due to potential neonatal toxicity. |
Clinical note
Comprehensive clinical and safety monograph for NALLPEN IN PLASTIC CONTAINER (NALLPEN IN PLASTIC CONTAINER).
| Placental transfer | Nafcillin crosses the placenta, achieving fetal serum concentrations approximately 10-15% of maternal levels. Transfer is moderate and protein-binding dependent. |
| Breastfeeding | Nafcillin is excreted in breast milk in low concentrations. Risk of diarrhea and allergic sensitization in nursing infants. Consider benefits of breastfeeding against potential risks. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to nafcillin or any penicillinHistory of IgE-mediated anaphylactic reaction to beta-lactams
| 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 |
| Food/Dietary | No significant food interactions reported. However, alcohol consumption should be avoided due to potential hepatotoxicity. No dietary restrictions required. |
| Clinical Pearls |
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| Lactation Rating | L2 (Limited data - probably compatible) |
| 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 | 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. |
| NALLPEN (nafcillin) is a penicillinase-resistant penicillin indicated for staphylococcal infections. Use with caution in patients with hypersensitivity to penicillins; cross-allergenicity with cephalosporins exists. Monitor hepatic function due to potential hepatotoxicity. Adjust dose in renal impairment for very high doses; nafcillin is primarily hepatically cleared. Compatible with most IV solutions, but avoid mixing with aminoglycosides. Administer slowly IV to avoid phlebitis. |
| Patient Advice | Complete the full course of antibiotics even if you feel better. · Report any signs of allergic reaction (rash, itching, swelling, difficulty breathing) immediately. · Avoid alcohol while on this medication as it may increase risk of liver damage. · Take missed doses as soon as remembered unless close to next dose; do not double dose. · Inform your doctor if you have kidney or liver disease, or if you are pregnant or breastfeeding. |