CYCLACILLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CYCLACILLIN (CYCLACILLIN).
Cyclacillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to cell lysis and death.
| Metabolism | Cyclacillin is primarily renally excreted unchanged; minimal hepatic metabolism occurs. |
| Excretion | Primarily renal (90%) as unchanged drug via glomerular filtration and tubular secretion; negligible biliary/fecal elimination (<5%). |
| Half-life | 0.5–1 hour in adults with normal renal function; prolonged to 10–15 hours in anuria. |
| Protein binding | 25% bound to serum albumin. |
| Volume of Distribution | 0.3–0.4 L/kg; distributes into extracellular fluid and inflamed tissues. |
| Bioavailability | Oral: 50–60% (dose-dependent, reduced by food). |
| Onset of Action | Oral: 1–2 hours; IM: 30–60 minutes. |
| Duration of Action | 4–6 hours; renal impairment extends duration. |
250-500 mg orally every 6 hours.
| Dosage form | TABLET |
| Renal impairment | CrCl >50 mL/min: 250-500 mg every 6 hours; CrCl 10-50 mL/min: 250-500 mg every 12 hours; CrCl <10 mL/min: 250-500 mg every 24 hours. |
| Liver impairment | No adjustment required. Hepatic impairment does not significantly affect cyclacillin pharmacokinetics. |
| Pediatric use | Children >20 kg: 250-500 mg orally every 6 hours; Children <20 kg: 12.5-25 mg/kg/day divided every 6 hours. |
| Geriatric use | No specific adjustment; monitor renal function and adjust based on creatinine clearance as per adult renal guidelines. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CYCLACILLIN (CYCLACILLIN).
| Breastfeeding | Excreted in breast milk in low concentrations; M/P ratio not established. Considered compatible with breastfeeding. |
| Teratogenic Risk | No evidence of teratogenicity in animal studies; limited human data. Pregnancy category B. No known fetal risk in any trimester. |
| Fetal Monitoring | No specific monitoring required beyond standard pregnancy care. |
■ FDA Black Box Warning
No FDA boxed warning exists for cyclacillin.
| Serious Effects |
["History of hypersensitivity to penicillins or cephalosporins."]
| Precautions | ["Serious and occasionally fatal hypersensitivity reactions (anaphylaxis) have been reported.","Prolonged use may result in overgrowth of nonsusceptible organisms.","Use cautiously in patients with renal impairment."] |
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| Fertility Effects | No known adverse effects on fertility. |