CEFADROXIL
Clinical safety rating: safe
Human studies have proved safety
Cefadroxil is a first-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), thereby inhibiting transpeptidase activity and disrupting peptidoglycan cross-linking.
| Metabolism | Cefadroxil is not significantly metabolized; it is primarily excreted unchanged in the urine via glomerular filtration and tubular secretion. |
| Excretion | Primarily renal (90-95% unchanged via glomerular filtration and tubular secretion); minor biliary/fecal (<5%). |
| Half-life | Terminal elimination half-life 1.1-1.5 hours in normal renal function; prolonged to 20-30 hours in end-stage renal disease (CrCl <10 mL/min). |
| Protein binding | 20% bound to serum proteins (primarily albumin). |
| Volume of Distribution | 0.15 L/kg, indicating limited distribution primarily to extracellular fluid. |
| Bioavailability | Oral: 95-100% (well absorbed from GI tract). |
| Onset of Action | Oral: peak serum concentrations at 1-2 hours; clinical effect begins within 1-2 hours. |
| Duration of Action | 12-24 hours depending on dose and renal function; once-daily dosing for most infections due to prolonged urinary levels. |
1-2 g orally once daily or divided into two doses every 12 hours.
| Dosage form | CAPSULE |
| Renal impairment | CrCl 30-59 mL/min: 500 mg every 12 hours; CrCl 10-29 mL/min: 500 mg every 24 hours; CrCl <10 mL/min: 500 mg every 36 hours. |
| Liver impairment | No dose adjustment required for hepatic impairment. |
| Pediatric use | 30 mg/kg/day orally divided into two doses every 12 hours; maximum 2 g/day. |
| Geriatric use | Renal function should be monitored; adjust dose based on creatinine clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Probenecid may decrease cephalosporin excretion Nephrotoxicity may occur with concurrent use of potent diuretics.
| Breastfeeding | Cefadroxil is excreted into breast milk in small amounts (M/P ratio not established, but likely <1). It is considered compatible with breastfeeding by the American Academy of Pediatrics. Monitor infant for diarrhea, candidiasis, or allergic reaction. |
| Teratogenic Risk | Cefadroxil is a first-generation cephalosporin classified as FDA Pregnancy Category B. Animal studies have not demonstrated fetal harm, but no adequate human studies exist. First trimester: Limited data; theoretical risk low. Second and third trimesters: No known teratogenicity; commonly used for UTIs and other infections. Overall, risk is considered low, but use only if clearly needed. |
■ FDA Black Box Warning
No FDA black box warning has been issued for cefadroxil.
| Common Effects | Diarrhea |
| Serious Effects |
["Hypersensitivity to cephalosporins or any component of the formulation","Hypersensitivity to penicillins (cross-sensitivity may occur)"]
| Precautions | ["Serious hypersensitivity reactions (anaphylaxis) may occur, especially in patients with penicillin allergy.","Pseudomembranous colitis caused by Clostridium difficile has been reported.","Dosage adjustment is required in patients with renal impairment (creatinine clearance <50 mL/min).","Prolonged use may result in superinfection with resistant organisms."] |
| Food/Dietary | Cefadroxil absorption is reduced by dairy products (milk, yogurt, cheese) and calcium-fortified foods/juices. Avoid taking with these items. Administer at least 1 hour before or 2 hours after meals to minimize variability, but food does not significantly affect absorption of ceftibuten-like cephalosporins; however, for cefadroxil, food may delay absorption but does not affect total absorption. To ensure consistent absorption, take on an empty stomach if possible. |
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| Fetal Monitoring | Monitor maternal renal function and signs of hypersensitivity. No specific fetal monitoring required beyond routine prenatal care. For prolonged therapy, monitor for superinfection or Clostridioides difficile colitis. |
| Fertility Effects | No known adverse effects on fertility in animal studies. In humans, no data suggesting impairment of male or female reproductive function. |
| Clinical Pearls | Cefadroxil is a first-generation cephalosporin with a long half-life allowing once-daily or twice-daily dosing. It is active against Streptococcus pyogenes and Staphylococcus aureus (MSSA). Use with caution in renal impairment; dose adjustment required for CrCl <50 mL/min. Cross-allergenicity with penicillins is possible but low. Can cause false-positive direct Coombs test and urine glucose test if using Clinitest. Avoid in patients with immediate hypersensitivity to cephalosporins. |
| Patient Advice | Take exactly as prescribed, even if you feel better. Complete the full course. · Do not take with dairy products (milk, yogurt, cheese) or calcium-fortified juices; space by at least 2 hours. · May cause diarrhea; contact your doctor if watery or bloody stools occur. · Notify your doctor of any rash, itching, or difficulty breathing. · Store at room temperature, away from moisture and heat. |