Abaclor

Approved Indications:

• Upper Respiratory Tract Infections:
• Pharyngitis and tonsillitis caused by Streptococcus pyogenes
• Acute bacterial sinusitis
• Otitis media caused by Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis
• Lower Respiratory Tract Infections:
• Acute bronchitis and exacerbations of chronic bronchitis
• Mild-to-moderate pneumonia caused by susceptible organisms
• Skin and Skin Structure Infections:
• Caused by Staphylococcus aureus and Streptococcus pyogenes
• Urinary Tract Infections (UTIs):
• Including cystitis and pyelonephritis due to E. coli, Proteus mirabilis, and Klebsiella spp.

Clinically Accepted Off-Label Uses:

• Treatment of early Lyme disease (alternative to doxycycline in children)
• Prophylaxis or treatment of recurrent streptococcal tonsillitis in penicillin-allergic patients

Route of Administration: Oral (capsules, tablets, or suspension)

Adults and Adolescents (≥13 years):

• Pharyngitis/Tonsillitis, Skin infections, Uncomplicated UTIs:
• 250 mg every 8 hours for 7–10 days
• Severe infections or lower respiratory tract infections:
• 500 mg every 8 hours for 7–10 days

Pediatric Patients (≥1 month):

• Usual Dose:
• 20–40 mg/kg/day divided into 3 doses
• Otitis media or more severe infections:
• Up to 40 mg/kg/day in 3 divided doses (maximum 1 g/day)
• Duration: Typically 5–10 days depending on indication

Geriatric Use:

• No specific adjustment required solely based on age; monitor renal function

Renal Impairment:

• Mild to moderate: No adjustment necessary
• Severe (CrCl <10 mL/min): Reduce frequency or dose interval
• Hemodialysis: Administer after dialysis session

Hepatic Impairment:

• No dose adjustment necessary

Cefaclor is a second-generation cephalosporin antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This action blocks the final transpeptidation step of peptidoglycan synthesis, which is essential for bacterial cell wall integrity. The resulting weakened wall leads to osmotic instability and bacterial cell lysis. It exhibits bactericidal activity and is effective against many Gram-positive and selected Gram-negative organisms.

• Absorption: Rapidly and well absorbed from the gastrointestinal tract; oral bioavailability ~90%
• Peak Plasma Time: 0.5–1 hour after administration
• Distribution: Widely distributed in body fluids and tissues; crosses placenta and appears in breast milk
• Protein Binding: ~25%
• Metabolism: Minimal hepatic metabolism
• Elimination Half-life: ~0.6–0.9 hours
• Excretion: Primarily excreted unchanged in the urine (60–85%) within 8 hours
• Accumulation: May occur in renal impairment

• Pregnancy:
• FDA Category B: Animal studies show no fetal risk; no adequate human data. Use if clearly needed.
• Lactation:
• Excreted in low amounts into breast milk
• Generally considered safe during breastfeeding; monitor infants for gastrointestinal disturbances (e.g., diarrhea or candidiasis)
• Caution: Use during pregnancy and lactation only when clearly necessary.

• Primary Class: Second-generation cephalosporin antibiotic
• Subclass: β-lactam antibiotic
• Antibacterial Spectrum: Broad, covering Gram-positive cocci and select Gram-negative bacilli

• Known hypersensitivity to cefaclor, other cephalosporins, or any formulation component
• History of severe hypersensitivity (e.g., anaphylaxis) to penicillins
• Previous serum sickness-like reactions to cefaclor

• Hypersensitivity Reactions: Risk of anaphylaxis; cross-reactivity with penicillins
• Clostridioides difficile–Associated Diarrhea (CDAD): May occur; evaluate in patients with severe diarrhea
• Renal Function Monitoring: Especially in prolonged therapy or in patients with impaired renal function
• Superinfection Risk: Prolonged use may lead to fungal or resistant bacterial overgrowth
• Serum Sickness–Like Reactions: Especially in pediatric patients (rash, arthralgia, fever)

Common:

• Gastrointestinal: Diarrhea, nausea, vomiting, abdominal pain
• Skin: Rash, urticaria, pruritus
• CNS: Headache, dizziness
• General: Vaginal candidiasis in women

Serious/Rare:

• Hypersensitivity: Anaphylaxis, angioedema, bronchospasm
• Hematologic: Eosinophilia, thrombocytopenia, hemolytic anemia
• Hepatic: Transient liver enzyme elevations, cholestatic jaundice
• Renal: Interstitial nephritis (rare)
• Serum sickness-like reactions: More common in children; symptoms include arthralgia, fever, rash

Onset and Dose-dependence:

• GI symptoms typically occur within the first few days
• Serum sickness-like reactions often appear after 5–10 days

• Probenecid: Inhibits renal excretion of cefaclor, increasing serum levels
• Warfarin: Cephalosporins may enhance anticoagulant effect (monitor INR)
• Oral Contraceptives: Theoretical reduction in effectiveness; recommend additional contraception
• Live vaccines (e.g., typhoid): May reduce vaccine efficacy
• Alcohol: No known direct interaction, but caution in patients with GI intolerance
• CYP Involvement: Not metabolized by CYP450 system

• Clinical guidelines continue to list cefaclor as an alternative treatment for streptococcal pharyngitis in penicillin-allergic patients.
• Recent pediatric updates caution against routine use due to serum sickness-like reactions, especially with repeated exposure.
• Resistance trends: Increasing resistance among H. influenzae and M. catarrhalis noted in surveillance data; culture-guided therapy is preferred.

• Capsules/Tablets:
• Store at 20°C to 25°C (68°F to 77°F)
• Protect from moisture and light
• Keep in tightly closed containers
• Oral Suspension (Dry Powder):
• Store unopened bottle at 20°C to 25°C
• After reconstitution, store in refrigerator at 2°C to 8°C (36°F to 46°F)
• Discard unused portion after 14 days
• Handling:
• Shake well before each use
• Do not freeze the reconstituted suspension