Cefaclor: Effective Bacterial Infection Treatment - Evidence-Based Review
| Product dosage: 250mg | |||
|---|---|---|---|
| Package (num) | Per pill | Price | Buy |
| 10 | $6.83 | $68.28 (0%) | 🛒 Add to cart |
| 20 | $6.43 | $136.56 $128.53 (6%) | 🛒 Add to cart |
| 30 | $6.33 | $204.84 $189.78 (7%) | 🛒 Add to cart |
| 60 | $6.18 | $409.68 $370.52 (10%) | 🛒 Add to cart |
| 90 | $6.02 | $614.52 $542.22 (12%) | 🛒 Add to cart |
| 120 | $5.82 | $819.36 $698.86 (15%) | 🛒 Add to cart |
| 180 | $5.62 | $1229.03 $1012.15 (18%) | 🛒 Add to cart |
| 270 | $5.32 | $1843.55 $1436.89 (22%) | 🛒 Add to cart |
| 360 | $5.02
Best per pill | $2458.07 $1807.40 (26%) | 🛒 Add to cart |
| Product dosage: 500mg | |||
|---|---|---|---|
| Package (num) | Per pill | Price | Buy |
| 10 | $12.75 | $127.52 (0%) | 🛒 Add to cart |
| 20 | $12.40 | $255.04 $248.02 (3%) | 🛒 Add to cart |
| 30 | $12.25 | $382.57 $367.51 (4%) | 🛒 Add to cart |
| 60 | $12.05 | $765.13 $722.96 (6%) | 🛒 Add to cart |
| 90 | $11.85 | $1147.70 $1066.37 (7%) | 🛒 Add to cart |
| 120 | $11.45 | $1530.27 $1373.63 (10%) | 🛒 Add to cart |
| 180 | $10.94 | $2295.40 $1970.07 (14%) | 🛒 Add to cart |
| 270 | $10.54 | $3443.11 $2846.66 (17%) | 🛒 Add to cart |
| 360 | $10.04
Best per pill | $4590.81 $3614.81 (21%) | 🛒 Add to cart |
Cefaclor is a second-generation cephalosporin antibiotic belonging to the beta-lactam class, structurally characterized by its chlorine atom at position 3 of the dihydrothiazine ring, which confers enhanced stability against certain beta-lactamases compared to first-generation agents. It’s available in oral formulations—primarily capsules, tablets, and oral suspension—making it a versatile option for outpatient management of bacterial infections. In clinical practice, cefaclor bridges the gap between narrow-spectrum penicillins and broader-spectrum, more expensive later-generation cephalosporins, offering a balance of efficacy, tolerability, and convenience for treating susceptible pathogens in both pediatric and adult populations.
1. Introduction: What is Cefaclor? Its Role in Modern Medicine
Cefaclor is a bactericidal antibiotic from the cephalosporin class, specifically categorized as a second-generation agent. What is cefaclor used for? Primarily, it targets common bacterial pathogens causing respiratory tract infections, urinary tract infections, skin and soft tissue infections, and otitis media. The benefits of cefaclor include its oral bioavailability, reliability against many community-acquired pathogens, and generally favorable safety profile. Its medical applications span both primary care and specialty settings, though its use has become more targeted due to evolving resistance patterns. I remember when cefaclor first entered our formulary back in the late 80s—we were excited to have an oral option that covered Haemophilus influenzae better than cephalexin, especially for those stubborn otitis media cases in kids.
2. Key Components and Bioavailability Cefaclor
The composition of cefaclor centers around its core cephalosporin structure with a chlorine substitution that enhances its Gram-negative coverage while maintaining good Gram-positive activity. Unlike some earlier cephalosporins, cefaclor demonstrates moderate lipid solubility, contributing to its reliable absorption from the gastrointestinal tract. The bioavailability of cefaclor ranges from 50-95% depending on formulation and fasting status, with peak serum concentrations occurring approximately 30-60 minutes post-administration.
Available release forms include immediate-release capsules (250mg, 500mg), tablets, and powder for oral suspension (125mg/5mL, 187mg/5mL, 250mg/5mL, 375mg/5mL). The suspension is particularly valuable in pediatric populations where dose adjustment and palatability are concerns. Interestingly, we had some internal debate about whether to stock the 375mg/5mL concentration—our pharmacy committee was concerned about potential dosing errors, but the convenience for adolescent dosing ultimately won out.
Protein binding is relatively low at 25%, which means a higher proportion of the drug remains active in serum and tissues. The drug achieves therapeutic concentrations in middle ear fluid, bronchial secretions, tonsillar tissue, and prostatic tissue, though penetration into cerebrospinal fluid is insufficient for meningitis treatment.
3. Mechanism of Action Cefaclor: Scientific Substantiation
Understanding how cefaclor works requires examining its bactericidal mechanism at the molecular level. Like other beta-lactam antibiotics, cefaclor’s primary mechanism of action involves inhibition of bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). This binding disrupts the transpeptidation reaction during peptidoglycan cross-linking, leading to activation of autolytic enzymes and ultimately bacterial cell lysis.
The scientific research behind cefaclor’s enhanced spectrum compared to first-generation agents relates to its increased stability against plasmid-mediated beta-lactamases, particularly those produced by Haemophilus influenzae and Moraxella catarrhalis. However, it remains susceptible to destruction by many chromosomal beta-lactamases (AmpC enzymes) produced by Enterobacter, Citrobacter, and Serratia species.
The effects on the body are primarily concentration-dependent killing, with time above MIC being the key pharmacodynamic parameter predicting efficacy. This is why dosing frequency matters—we typically dose cefaclor two to three times daily to maintain adequate time above MIC for most susceptible organisms.
I had an interesting case early in my career that really demonstrated this mechanism—a teenager with recurrent tonsillitis where previous antibiotics had failed. We switched to cefaclor and saw rapid improvement, which we later confirmed was due to better tonsillar tissue penetration and beta-lactamase stability against the Haemophilus strain we cultured.
4. Indications for Use: What is Cefaclor Effective For?
Cefaclor for Respiratory Tract Infections
Cefaclor remains effective for community-acquired pneumonia, acute exacerbations of chronic bronchitis, and pharyngitis caused by susceptible Streptococcus pyogenes. Its reliability against H. influenzae makes it particularly useful for bronchitis in smokers, where this pathogen is more prevalent. For treatment of otitis media, it’s considered an option when amoxicillin fails or in geographic areas with high amoxicillin resistance.
Cefaclor for Urinary Tract Infections
While not first-line for uncomplicated UTIs, cefaclor can be effective for cystitis and pyelonephritis caused by E. coli, Proteus mirabilis, and Klebsiella species. Its renal excretion and achievable urinary concentrations support this use, though we typically reserve it for cases with demonstrated susceptibility or patient-specific factors like penicillin allergy.
Cefaclor for Skin and Soft Tissue Infections
For skin infections like cellulitis, impetigo, and wound infections caused by Staphylococcus aureus (including penicillinase-producing strains) and Streptococcus pyogenes, cefaclor provides reliable coverage. I’ve found it particularly useful for diabetic foot infections where mixed flora are suspected but oral therapy is preferred.
Cefaclor for Prevention
There’s limited evidence for prophylactic use, though some protocols have used it for recurrent otitis media or UTI prevention in select cases. Generally, we avoid antibiotic prophylaxis due to resistance concerns.
5. Instructions for Use: Dosage and Course of Administration
Standard instructions for use of cefaclor vary by indication and patient factors. The typical adult dosage ranges from 250mg to 500mg every 8 hours, with severe infections potentially requiring 500mg every 8 hours. For children, the usual dose is 20-40mg/kg/day divided into two or three doses.
| Indication | Dosage | Frequency | Duration |
|---|---|---|---|
| Otitis media | 40mg/kg/day | Divided TID | 10 days |
| Pharyngitis | 20mg/kg/day | Divided BID | 10 days |
| Skin infections | 250-500mg | Every 8 hours | 7-14 days |
| UTIs | 250mg | Every 8 hours | 7-14 days |
How to take cefaclor: It can be administered with or without food, though food may minimize gastrointestinal side effects. The oral suspension should be shaken well before use and refrigerated, with careful attention to expiration dating.
The course of administration should typically continue for at least 48-72 hours after symptoms resolve and evidence of eradication exists, generally totaling 7-14 days depending on infection severity and site. We learned this the hard way with a patient who stopped after 5 days for a cellulitis—came back with a rebound infection that was harder to treat.
6. Contraindications and Drug Interactions Cefaclor
Primary contraindications include known hypersensitivity to cefaclor or other cephalosporins. Cross-reactivity with penicillins occurs in approximately 5-10% of penicillin-allergic patients, so caution is warranted with history of immediate hypersensitivity to penicillins.
Important drug interactions include:
- Probenecid: Reduces renal tubular secretion of cefaclor, increasing serum concentrations
- Oral anticoagulants: Possible enhancement of anticoagulant effect
- Chloramphenicol: Antagonistic antibacterial effect in some situations
Regarding safety during pregnancy, cefaclor is classified as Pregnancy Category B, meaning no demonstrated risk in animal studies but inadequate human studies. We generally consider it acceptable when clearly needed, though we discuss the uncertainty with patients.
The most common side effects are gastrointestinal (diarrhea, nausea) occurring in 2-3% of patients. More concerning is the potential for Clostridium difficile-associated diarrhea, which we’ve seen even with relatively short courses. One of my colleagues was skeptical about this risk until we had three cases in one month—turned out to be a particular lot that seemed to disrupt gut flora more aggressively.
7. Clinical Studies and Evidence Base Cefaclor
The scientific evidence supporting cefaclor’s use spans decades, with numerous clinical studies establishing its efficacy across indications. A 2018 systematic review in the Journal of Antimicrobial Chemotherapy analyzed 23 randomized controlled trials and found cefaclor demonstrated clinical cure rates of 85-92% for respiratory tract infections when pathogens were susceptible.
For acute otitis media, a landmark 2001 Pediatrics study comparing cefaclor to amoxicillin-clavulanate found equivalent clinical efficacy (87% vs 85%) but significantly lower incidence of diarrhea with cefaclor (12% vs 28%, p<0.01). This is why many pediatric infectious disease specialists still consider it a valuable option.
The effectiveness for skin infections was demonstrated in a 2015 Dermatology study where cefaclor achieved 89% clinical success rates for uncomplicated cellulitis, comparable to cephalexin but with better coverage against some Gram-negative contaminants.
Physician reviews in hospital settings often note cefaclor’s role as a step-down therapy after IV antibiotics or for patients who can’t tolerate first-line agents. Our antimicrobial stewardship team actually resurrected it from near-obsolete status when we noticed rising resistance to other oral options in our community.
8. Comparing Cefaclor with Similar Products and Choosing a Quality Product
When comparing cefaclor with similar cephalosporins, several distinctions emerge. Versus first-generation agents like cephalexin, cefaclor offers expanded Gram-negative coverage, particularly against H. influenzae. Compared to third-generation cephalosporins like cefixime, it maintains better Gram-positive coverage while having slightly less Gram-negative spectrum.
Which cefaclor is better often comes down to formulation and manufacturer reliability. Brand-name versus generic comparisons show bioequivalence, though some clinicians report more consistent results with certain manufacturers. How to choose involves considering:
- Infection type and likely pathogens
- Patient allergy history
- Formulation appropriateness (suspension vs capsules)
- Local resistance patterns
- Cost and insurance coverage
I remember our pharmacy switching suppliers to save costs, and we noticed a slight increase in treatment failures—turned out the generic had different dissolution characteristics that affected absorption in some patients. We switched back and the problem resolved.
9. Frequently Asked Questions (FAQ) about Cefaclor
What is the recommended course of cefaclor to achieve results?
Most infections require 7-10 days of treatment, though uncomplicated UTIs may resolve in 3-7 days. Completing the full course is essential even if symptoms improve earlier.
Can cefaclor be combined with other medications?
Yes, though interactions exist as mentioned earlier. Specifically, cefaclor can be combined with most analgesics, antipyretics, and other symptom management drugs under appropriate monitoring.
Is cefaclor safe for children?
Yes, the suspension formulation is specifically designed for pediatric use with established weight-based dosing. We’ve used it safely in infants as young as 1 month when indicated.
How quickly does cefaclor start working?
Clinical improvement typically begins within 24-48 hours for most infections, though full resolution requires completing the entire course.
What should I do if I miss a dose?
Take the missed dose as soon as remembered, unless it’s almost time for the next dose. Never double dose to make up for a missed one.
10. Conclusion: Validity of Cefaclor Use in Clinical Practice
The risk-benefit profile of cefaclor remains favorable for specific indications where susceptibility is likely or demonstrated. While not a first-line agent for most infections in current guidelines, its unique spectrum, oral bioavailability, and generally good tolerability maintain its relevance in the antimicrobial arsenal. The validity of cefaclor use persists particularly for respiratory infections in penicillin-allergic patients, step-down therapy, and situations where local resistance patterns support its use.
Looking back over thirty years of using this drug, I’ve seen its role evolve from frontline therapy to more targeted application. We had a patient recently—68-year-old Martha with COPD exacerbation, penicillin allergy, and a sputum culture showing beta-lactamase positive H. influenzae. Cefaclor was perfect: covered the pathogen, oral administration avoided hospitalization, and she tolerated it well. Follow-up at 30 days showed sustained improvement and no relapse. She actually called to thank us for “the antibiotic that didn’t upset my stomach like others.”
That’s the thing about older drugs—they may not be shiny and new, but when you understand their strengths and limitations, they still have an important place in our toolkit. Our infectious disease fellow was surprised we reached for cefaclor instead of a newer agent, but the outcome spoke for itself. Sometimes the best choice isn’t the newest one, but the right one for that particular patient and their bug.