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. |
| Molecular Weight | 363.4 |
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 | Animal studies have not shown fetal harm; no adequate human studies in first trimester. Use only if clearly needed. |
| 2nd trimester | Generally considered safe; no evidence of teratogenicity. Use if indicated. |
| 3rd trimester | Considered safe; avoid near delivery if theoretical risk of infant gut flora alteration. |
Clinical note
Probenecid may decrease cephalosporin excretion Nephrotoxicity may occur with concurrent use of potent diuretics.
| Placental transfer | Cefadroxil crosses the placenta; fetal serum levels are approximately 10-20% of maternal serum levels after usual doses. |
| Breastfeeding | Cefadroxil is excreted in breast milk in low concentrations (less than 1% of maternal dose). Not expected to cause adverse effects in nursing infants. Use with caution in infants with G6PD deficiency or diarrhea. |
■ FDA Black Box Warning
No FDA black box warning has been issued for cefadroxil.
| Common Effects | Diarrhea |
| Serious Effects |
Hypersensitivity to cefadroxil or any cephalosporinSevere immediate hypersensitivity reactions to penicillins
| 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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| Lactation Rating | L1 |
| 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. |
| 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. |