Cefadroxil

# Cefadroxil ## Overview - **Classification**: First-generation Cephalosporin (beta-lactam antibiotic) - **Mechanism**: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs), leading to bacterial cell lysis and death. ## Primary Indications 1. **Skin and Skin Structure Infections**: Caused by susceptible *Staphylococcus* and *Streptococcus* species. 2. **Urinary Tract Infections (UTIs)**: Uncomplicated UTIs caused by susceptible organisms like *E. coli*, *Proteus mirabilis*, *Klebsiella* species. 3. **Pharyngitis/Tonsillitis**: Due to *Streptococcus pyogenes* (Group A Strep). ## Adult Dosing ### Standard Dosing **Skin and Skin Structure Infections** - **Dose**: **1 gram** - **Frequency**: Once daily (QD) OR **500 mg** twice daily (BID) - **Route**: Oral - **Duration**: 7-10 days, or until resolution of infection **Urinary Tract Infections (uncomplicated)** - **Dose**: **1 gram** - **Frequency**: Once daily (QD) OR **500 mg** twice daily (BID) - **Route**: Oral - **Duration**: 7-10 days **Pharyngitis/Tonsillitis (Streptococcus pyogenes)** - **Dose**: **1 gram** - **Frequency**: Once daily (QD) OR **500 mg** twice daily (BID) - **Route**: Oral - **Duration**: 10 days ### Dose Adjustments - **Renal Impairment**: - CrCl >50 mL/min: No adjustment. - CrCl 25-50 mL/min: **500 mg** every 24 hours. - CrCl 10-24 mL/min: **500 mg** every 36 hours. - CrCl <10 mL/min: **500 mg** every 48 hours. - Hemodialysis: Administer **500 mg** after dialysis on dialysis days. - **Hepatic Impairment**: No specific dose adjustment generally required. - **Elderly Patients**: Dose adjustments based on renal function are generally sufficient. Monitor renal function closely. ## Pediatric Dosing ### Neonates (0-28 days) - **Special Notes**: Cefadroxil is generally not recommended in neonates due to limited safety and efficacy data. Alternative antibiotics are preferred. ### Infants (1-12 months) - **Dose**: **30 mg/kg/day** - **Frequency**: Once daily (QD) or in two divided doses (BID) - **Maximum**: **100 mg/kg/day** (max **4 grams/day**) - **Special Notes**: Use oral suspension for accurate dosing. ### Children (1-12 years) - **Dose**: **30 mg/kg/day** - **Frequency**: Once daily (QD) or in two divided doses (BID) - **Maximum**: **100 mg/kg/day** (max **4 grams/day**) - **Special Notes**: For pharyngitis/tonsillitis (S. pyogenes), **30 mg/kg/day** once daily or BID for 10 days. Max **1 g/day**. ### Adolescents (13-18 years) - **Dose**: Refer to adult dosing guidelines. - **Maximum**: **4 grams/day**. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to cefadroxil or any cephalosporin antibiotic. - **Absolute**: History of severe immediate hypersensitivity reaction to penicillins (e.g., anaphylaxis). ### Common Adverse Effects - **Common (1-10%)**: Nausea, vomiting, diarrhea, abdominal pain, dyspepsia. - **Common (1-10%)**: Rash, pruritus, genital pruritus, vaginal candidiasis. - **Serious but Rare**: *Clostridioides difficile*-associated diarrhea (CDAD), severe cutaneous adverse reactions (e.g., SJS, TEN), anaphylaxis, angioedema. ### Key Drug Interactions - **Probenecid**: May increase cefadroxil plasma concentrations by decreasing renal excretion. Avoid concomitant use or monitor for toxicity. - **Oral Anticoagulants (e.g., Warfarin)**: May rarely enhance anticoagulant effect. Monitor INR/PT more frequently. - **Live Typhoid Vaccine**: Cefadroxil may reduce the therapeutic effect of oral typhoid vaccine. Administer vaccine at least 3 days after cefadroxil completion. ## Monitoring & Follow-up - **Before Treatment**: Assess history of allergies to cephalosporins or penicillins. - **During Treatment**: Monitor for signs of severe hypersensitivity reactions (rash, difficulty breathing). - **During Treatment**: Monitor for signs of superinfection (e.g., oral/vaginal candidiasis, C. difficile diarrhea). - **Clinical Signs**: Assess for resolution of infection symptoms. ## Clinical Pearls - 💡 **Administration**: Can be taken with food to minimize gastrointestinal upset. - 💡 **Suspension**: Reconstituted oral suspension should be refrigerated and discarded after 14 days. Shake well before each use. - 💡 **Compliance**: Emphasize completing the full course of therapy, even if symptoms improve, to prevent resistance and recurrence. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.