CEFADYL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CEFADYL (CEFADYL).
Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs), inhibiting transpeptidation and autolysin activation.
| Metabolism | Hepatic (minor); primarily excreted unchanged in urine via glomerular filtration and tubular secretion. |
| Excretion | Renal: 90-95% unchanged via glomerular filtration and tubular secretion. Biliary: <1%. Fecal: minimal. |
| Half-life | 30-60 minutes in adults with normal renal function; prolonged to 10-20 hours in end-stage renal disease. Requires dose adjustment for CrCl <30 mL/min. |
| Protein binding | 50-60% bound primarily to albumin. |
| Volume of Distribution | 0.12-0.18 L/kg. Indicates distribution primarily into extracellular fluid; limited CNS penetration unless inflamed meninges. |
| Bioavailability | IM: approximately 90%. |
| Onset of Action | IV: immediate; IM: 15-30 minutes. |
| Duration of Action | 6-8 hours in normal renal function; extended in renal impairment. Note: Short half-life necessitates frequent dosing (every 6 hours) for continuous bactericidal effect. |
1-2 g IV/IM every 6 hours for moderate to severe infections; maximum 12 g/day.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl >50 mL/min: no adjustment; CrCl 20-50 mL/min: 1-2 g every 8-12 hours; CrCl 10-20 mL/min: 1-2 g every 12-24 hours; CrCl <10 mL/min: 1-2 g every 24-48 hours. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic impairment as cefadyl is primarily renally eliminated. |
| Pediatric use | Children: 50-100 mg/kg/day IV/IM divided every 6 hours; maximum 12 g/day. Neonates: 50-100 mg/kg/day IV/IM divided every 12 hours. |
| Geriatric use | Adjust dose based on renal function; start at lower end of dosing range due to age-related decreased renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CEFADYL (CEFADYL).
| Breastfeeding | Cephapirin is excreted into human breast milk in small amounts. M/P ratio not established. It is considered compatible with breastfeeding; caution with nursing infants due to potential alteration of gut flora and diarrhea. |
| Teratogenic Risk | Cefadyl (cephapirin) is a first-generation cephalosporin. Animal studies have not shown teratogenic effects. In humans, there are no adequate and well-controlled studies in pregnant women. First trimester: Low risk; crosses placenta but no known teratogenicity. Second and third trimesters: Generally considered safe; use only if clearly needed. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to cephalosporins or penicillin derivatives; patients with immediate-type hypersensitivity reactions to penicillins (cross-sensitivity).
| Precautions | Hypersensitivity reactions including anaphylaxis; superinfection with prolonged use; Clostridioides difficile-associated diarrhea (CDAD); renal impairment (dose adjustment required); thrombophlebitis at injection site. |
| Food/Dietary | No known direct food interactions. However, avoid alcohol (including in medications, mouthwash, or foods) during therapy and for 48 hours after discontinuation due to risk of disulfiram-like reaction (nausea, vomiting, flushing, headache). |
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| Fetal Monitoring | Monitor maternal renal function and signs of hypersensitivity. Fetal monitoring not routinely required unless maternal infection poses risk to fetus. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data not available. |
| Clinical Pearls |
| CEFADYL (cephapirin) is a first-generation cephalosporin with good activity against gram-positive cocci including penicillinase-producing Staphylococcus aureus. It is not active against MRSA or enterococci. Use with caution in patients with penicillin allergy due to cross-reactivity. Administer intramuscularly or intravenously; avoid subcutaneous or intra-arterial injection. Monitor renal function in elderly or renally impaired patients; adjust dose if creatinine clearance <30 mL/min. Pain at injection site is common; rotate sites if repeated IM use. |
| Patient Advice | Complete the full course of antibiotics even if you feel better to prevent resistance. · Inform your doctor if you are allergic to penicillin or cephalosporins. · This medication may cause diarrhea; report severe or bloody diarrhea to your doctor. · Avoid alcohol during treatment and for 48 hours after the last dose to prevent disulfiram-like reaction. · Take as prescribed; missed doses should be taken as soon as remembered unless close to next dose. |