BACTOCILL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BACTOCILL (BACTOCILL).
BACTOCILL (nafcillin) is a penicillinase-resistant penicillin that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), thereby inhibiting transpeptidation and autolysin inhibitors. Active against Staphylococcus aureus and other gram-positive bacteria.
| Metabolism | Hepatic metabolism via non-cytochrome P450 pathways; primarily metabolized via hydrolysis to penicilloic acid (major) and other minor metabolites. Excreted primarily in bile (80%) and urine (20%). Half-life: ~0.5-1 hour. |
| Excretion | Renal: 60-70% unchanged; biliary: 20-30% as active metabolite; fecal: 5-10% |
| Half-life | 0.5-0.8 hours; prolonged to 2-4 hours in severe renal impairment |
| Protein binding | 94-98%, primarily to serum albumin |
| Volume of Distribution | 0.3-0.4 L/kg; indicates distribution mainly in extracellular fluid |
| Bioavailability | IM: 70-80%; oral: not applicable (inactivated by gastric acid) |
| Onset of Action | IV: immediate; IM: 15-30 minutes |
| Duration of Action | 6-8 hours; dosing interval typically 4-6 hours |
250-500 mg orally every 6 hours or 1-2 g intravenously every 4-6 hours
| Dosage form | CAPSULE |
| Renal impairment | CrCl 10-50 mL/min: administer every 6-8 hours; CrCl <10 mL/min: administer every 8-12 hours |
| Liver impairment | No dose adjustment required for mild-moderate hepatic impairment; use with caution in severe impairment (Child-Pugh C) with monitoring |
| Pediatric use | Children >1 month: 12.5-25 mg/kg orally every 6 hours or 50-100 mg/kg/day intravenously divided every 4-6 hours; neonates (<1 month): 25 mg/kg intravenously every 8 hours |
| Geriatric use | No specific dose adjustment; monitor renal function and reduce dose according to creatinine clearance |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BACTOCILL (BACTOCILL).
| Breastfeeding | Lactation summary: BACTOCILL is excreted in human milk in trace amounts. The milk-to-plasma (M/P) ratio is approximately 0.1–0.2. At therapeutic maternal doses, effects on the nursing infant are unlikely. However, caution should be exercised when administering to a nursing woman due to the potential for allergic reactions or alteration of infant gut flora. |
| Teratogenic Risk | Teratogenic risk profile: In animal reproduction studies, no evidence of fetal harm at doses up to 4 times the human dose. However, adequate and well-controlled studies in pregnant women are lacking. Therefore, BACTOCILL should be used during pregnancy only if clearly needed. First trimester: No specific teratogenic effects identified; risks are considered low. Second and third trimesters: No known increase in fetal risk; however, due to limited human data, caution is advised. |
■ FDA Black Box Warning
Serious and occasionally fatal hypersensitivity reactions (e.g., anaphylaxis) have been reported in patients on penicillin therapy. The incidence of such reactions is higher in patients with a history of penicillin allergy and/or history of sensitivity to multiple allergens.
| Serious Effects |
History of hypersensitivity to nafcillin, penicillins, or any component of the formulation; history of severe hypersensitivity (anaphylaxis) to other beta-lactams (e.g., cephalosporins) due to cross-reactivity; caution in patients with allergic diathesis.
| Precautions | Hypersensitivity reactions including anaphylaxis; severe cutaneous adverse reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis; caution in patients with renal impairment; associated with hepatotoxicity (especially in high doses); monitor for bone marrow suppression; use in neonates may cause kernicterus; prolonged use may result in superinfection due to resistant organisms. |
| Food/Dietary | No significant food interactions. Avoid alcohol during treatment to reduce risk of hepatotoxicity. |
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| Fetal Monitoring | Maternal-fetal monitoring: Monitor maternal vital signs, renal function, and hepatic function periodically during therapy. Fetal monitoring includes assessment of fetal heart rate and growth if used for prolonged periods. Observe for signs of maternal hypersensitivity reactions or superinfection. |
| Fertility Effects | Fertility effects: Animal studies have shown no impairment of fertility at clinically relevant doses. There are no adequate human studies on fertility; based on available data, no significant effects on fertility are anticipated. |
| Clinical Pearls | BACTOCILL (nafcillin) is a penicillinase-resistant penicillin used for infections caused by susceptible staphylococci. It is not active against MRSA. Administer via IV or IM; oral absorption is poor. Monitor for hepatotoxicity and neutropenia with prolonged use. In patients with renal impairment, dose adjustment is not required; however, caution in hepatic impairment. Use with care in patients with a history of penicillin allergy. Cross-allergenicity with cephalosporins occurs in less than 10% of cases. Consider desensitization in severe hypersensitivity. |
| Patient Advice | Take this medication exactly as prescribed, even if you feel better. · Complete the full course of therapy to prevent resistance. · Report any signs of allergic reaction: rash, hives, itching, difficulty breathing, or swelling of face/mouth. · Notify your doctor if you experience severe diarrhea, nausea, vomiting, or yellowing of skin/eyes. · This drug is given intravenously or intramuscularly; do not take orally unless specifically directed. |