Ridicef

Approved Indications:

• Acute bacterial otitis media (AOM): In children ≥6 months caused by Streptococcus pneumoniae, Haemophilus influenzae (including β-lactamase–producing strains), and Moraxella catarrhalis.
• Acute maxillary sinusitis: Caused by susceptible strains of S. pneumoniae, H. influenzae, and M. catarrhalis.
• Pharyngitis and tonsillitis: Caused by Streptococcus pyogenes.
• Community-acquired pneumonia (CAP): Mild to moderate, caused by S. pneumoniae, H. influenzae, or M. catarrhalis.
• Acute exacerbations of chronic bronchitis (AECB): Caused by S. pneumoniae, H. influenzae, and M. catarrhalis.
• Uncomplicated skin and skin structure infections (uSSSI): Including cellulitis, impetigo, and wound infections caused by Staphylococcus aureus (methicillin-susceptible strains only) and S. pyogenes.

Clinically Accepted Off-Label Uses:

• Not routinely recommended for off-label use due to better alternatives in most cases.
• Occasionally used in settings where first-line agents are contraindicated or in penicillin-allergic individuals.

Adults and Adolescents (≥13 years):

• CAP, AECB, Sinusitis: 300 mg orally every 12 hours or 600 mg once daily for 5–10 days.
• Pharyngitis/Tonsillitis, Skin infections: 300 mg orally every 12 hours or 600 mg once daily for 10 days.

Pediatrics (6 months–12 years):

• Pharyngitis/Tonsillitis: 7 mg/kg every 12 hours or 14 mg/kg once daily for 10 days (max 600 mg/day).
• AOM, Skin Infections, Sinusitis: 7 mg/kg every 12 hours for 5–10 days or 14 mg/kg once daily for 10 days (max 600 mg/day).

Renal Impairment:

• If creatinine clearance <30 mL/min, the dosing frequency should be reduced to once daily (both in adults and pediatrics).

Hepatic Impairment:

• No specific dosage adjustment necessary.

Administration Notes:

• Can be taken with or without food.
• Do not administer with iron-containing supplements or antacids (separate by at least 2 hours).

Cefdinir is a third-generation oral cephalosporin antibiotic that inhibits bacterial cell wall synthesis. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, thereby interfering with the final transpeptidation step of peptidoglycan synthesis. This leads to weakened cell wall integrity, bacterial cell lysis, and death. Cefdinir exhibits bactericidal activity against a wide range of Gram-positive and Gram-negative organisms, especially those commonly involved in respiratory and skin infections.

• Absorption: Oral bioavailability is approximately 16–21%. Peak plasma concentration occurs within 2–4 hours post-dose.
• Distribution: Widely distributed; protein binding ~60–70%.
• Metabolism: Not significantly metabolized; exerts activity in unchanged form.
• Elimination: Primarily excreted unchanged via the kidneys (~18% of the dose recovered in urine over 24 hours).
• Half-life: Approximately 1.7 hours (may be prolonged in renal impairment).
• Food effect: High-fat meals may slightly delay absorption but do not significantly affect the extent.

• Pregnancy: Classified as Category B (FDA). Animal studies have shown no teratogenic effects; however, no adequate well-controlled studies exist in pregnant women. Use only if clearly needed.
• Lactation: Cefdinir is excreted in trace amounts in breast milk. Although generally considered safe during breastfeeding, potential for alteration of gut flora or sensitization exists. Caution is advised, and infants should be monitored for gastrointestinal disturbances (e.g., diarrhea, candidiasis).

• Primary Class: Third-generation cephalosporin antibiotic
• Subclass: Oral cephalosporin
• Pharmacologic Class: β-lactam antibacterial

• Known hypersensitivity to cefdinir, cephalosporins, or β-lactam antibiotics.
• Documented history of severe hypersensitivity (e.g., anaphylaxis, Stevens-Johnson Syndrome) to penicillins or other β-lactams.
• Neonates and infants <6 months (due to limited safety data).

• Hypersensitivity Reactions: Cross-reactivity with penicillins; discontinue immediately if allergic reaction occurs.
• Clostridioides difficile–associated diarrhea (CDAD): May range from mild to fatal colitis; consider in patients with diarrhea.
• Renal Impairment: Dose adjustments required; accumulation may lead to toxicity.
• Iron-Containing Products: Concomitant use reduces absorption; separate dosing advised.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including Candida or Clostridium difficile.
• Seizures: Rare reports, especially in renal impairment or with high doses.
• Use in Diabetes: The oral suspension contains sucrose; use caution in diabetic patients.

Common (≥1%):

• Gastrointestinal: Diarrhea, nausea, abdominal pain, vomiting.
• Dermatologic: Rash, especially in pediatric patients.
• CNS: Headache, dizziness.

Less Common (<1%):

• Vaginitis, pruritus, flatulence, candidiasis.

Serious or Rare:

• Stevens-Johnson Syndrome, erythema multiforme.
• Anaphylaxis.
• Clostridioides difficile–associated diarrhea.
• Hepatic dysfunction (elevated transaminases).
• Hematologic: Eosinophilia, thrombocytopenia (rare).

• Antacids containing magnesium or aluminum: Significantly reduce absorption of cefdinir. Separate doses by ≥2 hours.
• Iron supplements or iron-containing foods: Reduce cefdinir absorption by up to 80%; may also cause red stools in children.
• Probenecid: May increase serum levels of cefdinir by reducing renal clearance.
• Oral contraceptives: Efficacy may be reduced; additional contraceptive measures advised.
• No major CYP450 involvement: Not a substrate or significant inducer/inhibitor.

• 2023–2025 Updates: No major changes to dosage, indications, or black box warnings reported by FDA or EMA.
• Clinical Practice Guidelines (IDSA, AAP): Continue to include cefdinir as an alternative treatment for AOM and pharyngitis in penicillin-allergic patients.
• Antibiotic Stewardship Recommendations: Cefdinir should not be used empirically for infections with known resistance to third-generation cephalosporins.

• Capsules: Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C–30°C (59°F–86°F).
• Oral suspension (dry powder): Store at room temperature before reconstitution.
• After reconstitution: Store reconstituted suspension at 20°C to 25°C, do not refrigerate, and discard after 10 days.
• Protect from moisture and light. Keep in original container tightly closed.