Cefuroxime

• Respiratory Tract Infections
• Lyme Disease
• Urinary Tract Infections
• Skin Infections

Cefuroxime (brand names Ceftin and Zinacef) is a second-generation cephalosporin antibiotic used to treat a wide range of bacterial infections, including respiratory tract infections, sinusitis, uncomplicated skin infections, certain urinary tract infections, and early Lyme disease. Available as oral tablets, oral suspension, and an intravenous formulation, it offers broader Gram-negative coverage than first-generation cephalosporins while retaining strong activity against many common Gram-positive pathogens. It is most useful when a beta-lactam is preferred and the suspected organisms include beta-lactamase-producing strains of Haemophilus influenzae or Moraxella catarrhalis, two organisms commonly responsible for upper and lower respiratory infections in adults and children alike.

Mechanism of Action

Cefuroxime is a beta-lactam antibiotic that exerts bactericidal activity by binding penicillin-binding proteins (PBPs) on the bacterial cell membrane. PBPs catalyze the transpeptidation step of peptidoglycan cross-linking that gives the bacterial cell wall its mechanical strength. By inhibiting these enzymes, cefuroxime weakens the cell wall during active growth and triggers autolytic cell death. Because cefuroxime resists hydrolysis by many common beta-lactamases (a defense mechanism many bacteria deploy against penicillins), it remains active against ampicillin-resistant H. influenzae and M. catarrhalis, organisms frequently implicated in upper respiratory infections. Its spectrum includes Streptococcus pneumoniae, methicillin-susceptible Staphylococcus aureus, group A Streptococcus, and many community Enterobacterales (E. coli, Klebsiella, Proteus mirabilis), but it does not cover atypical pathogens such as Mycoplasma or Legionella, methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, or enterococci. Activity details and pharmacokinetics are described in the FDA prescribing information.

Clinical Use

Cefuroxime is reasonable for acute bacterial sinusitis when amoxicillin or amoxicillin-clavulanate is not appropriate, and for acute otitis media in penicillin-allergic patients without severe reactions. It is one of several oral options for early localized Lyme disease in patients who cannot take doxycycline, with similar efficacy across a 14- to 21-day course in randomized trials. For acute exacerbations of chronic bronchitis with bacterial features, cefuroxime is a reasonable choice when an oral agent with H. influenzae and M. catarrhalis activity is needed. For uncomplicated cystitis, narrower agents such as nitrofurantoin or trimethoprim-sulfamethoxazole are usually preferred unless local resistance dictates otherwise; for skin and soft tissue infections, cephalexin covers most streptococci and MSSA at lower cost with twice-daily dosing tolerated well. The injectable form serves as surgical prophylaxis for clean and clean-contaminated procedures and as treatment for community-acquired pneumonia in inpatients. Antibiotic stewardship is critical: choosing the narrowest effective agent for the shortest necessary duration reduces collateral damage to the microbiome, limits selection of resistant organisms, and lowers the risk of Clostridioides difficile infection, a topic explored in our antibiotic resistance guide.

How to Take It

Cefuroxime axetil tablets are best absorbed when taken with food, which both increases bioavailability and reduces the metallic taste many patients describe. Tablets should be swallowed whole; crushing exposes a particularly bitter core that many patients find intolerable. The oral suspension uses a different chemical form and is not bioequivalent to the tablets on a milligram-for-milligram basis, so the two should not be substituted for one another. Take doses at evenly spaced intervals (typically every 12 hours) and complete the full prescribed course even if symptoms resolve early, since premature discontinuation invites relapse and selects for resistant organisms. If a dose is missed, take it as soon as remembered unless the next dose is near, in which case skip it and resume the regular schedule. Store tablets at room temperature away from moisture; reconstituted suspension should be refrigerated and discarded after the labeled period (usually 10 days). During the course, expect symptom improvement within 48 to 72 hours; if symptoms have not improved by then, contact your physician for reassessment.

Monitoring and Follow-Up

Most short courses do not require laboratory monitoring. For prolonged therapy, particularly in older adults or those with renal impairment, periodic CBC and metabolic panels are reasonable to detect cytopenias, eosinophilia, or rising creatinine; our lab panels overview describes what these tests reveal. Patients who develop watery diarrhea during or up to several weeks after the course should be evaluated for Clostridioides difficile infection; the CDC's overview explains warning signs and risk factors. Follow-up after a respiratory infection is typically symptom-driven; persistent or recurrent symptoms after seven to ten days warrants reassessment for treatment failure, resistant organisms, or an alternate diagnosis such as viral infection, atypical pneumonia, or noninfectious causes. After a Lyme disease course, follow-up testing for Lyme antibodies is generally not useful since titers can remain positive for years even after successful treatment.

Special Populations

For adults and pediatric patients with creatinine clearance below 30 mL/min, dose frequency is reduced; supplemental dosing is required after hemodialysis because the drug is partially removed. No dose adjustment is required for hepatic impairment, since cefuroxime is renally cleared. Cefuroxime is generally considered acceptable in pregnancy when an antibiotic is needed and the LactMed database lists it as compatible with breastfeeding because excretion into milk is low and clinically significant infant effects have not been reported. In children three months and older, weight-based dosing is well established for the suspension. Cross-reactivity with penicillins exists but is uncommon for second-generation cephalosporins; a careful allergy history should distinguish true IgE-mediated reactions from intolerance such as gastrointestinal upset. Patients with a history of severe penicillin reactions (anaphylaxis, Stevens-Johnson syndrome, drug reaction with eosinophilia and systemic symptoms) should avoid cephalosporins unless allergy evaluation supports their use.

Drug Interactions and Practical Pearls

Proton pump inhibitors such as omeprazole and H2 receptor antagonists raise gastric pH and can reduce absorption of cefuroxime axetil; if the patient must continue acid suppression, tell them to take cefuroxime with food, which mitigates the effect. Probenecid blocks renal tubular secretion and increases cefuroxime serum concentrations, occasionally used therapeutically but more often noted as a potential interaction. Concurrent aminoglycoside use modestly increases nephrotoxicity risk and warrants attention to renal function. Cefuroxime can produce false-positive urine glucose tests with copper reduction methods (Clinitest) and a positive direct Coombs test in a small percentage of patients. Concomitant warfarin may show modest INR fluctuations during antibiotic courses, though the effect is smaller than with fluoroquinolones or trimethoprim-sulfamethoxazole; INR monitoring within a few days of starting and finishing the antibiotic is reasonable in patients with previously stable anticoagulation. Oral contraceptive efficacy is a frequent patient concern; current evidence does not support clinically meaningful interaction with cefuroxime or other beta-lactams in non-rifampin antibiotic classes, but backup contraception during the course is a reasonable precaution. For patients with a history of mild penicillin reaction (rash, gastrointestinal upset), the cross-reactivity rate with second-generation cephalosporins is approximately 1-2 percent, lower than the historic 10 percent figure that derived from older preparations. Probiotic use during and after antibiotic courses, supported by limited but suggestive evidence, may reduce the incidence of antibiotic-associated diarrhea. Patients with prior C. difficile infection are at heightened risk of recurrence with any new antibiotic exposure and may warrant adjunctive prophylaxis; a discussion of risks and benefits before prescribing is essential. Our gut health article on prebiotics and probiotics covers practical strategies for protecting the microbiome.

When to Contact Your Doctor

Seek immediate care for hives, swelling of the face or throat, wheezing, or difficulty breathing, which may signal anaphylaxis. Severe or bloody diarrhea, persistent abdominal pain, or new fever during or after antibiotic use should prompt urgent evaluation for C. difficile colitis, which can occur even weeks after the course is complete. Yellowing of the skin or eyes, dark urine, easy bruising, or a new rash with mucous membrane involvement (such as oral ulcers, blistering, or eye redness) also warrant prompt assessment for hepatotoxicity, hemolytic anemia, or severe cutaneous reactions. If symptoms of the original infection are not improving by 48 to 72 hours, or if symptoms initially improve and then worsen, the antibiotic choice or diagnosis may need to be reconsidered, since both treatment failure and superinfection can present this way.

If you have an active infection, suspect Lyme disease after a tick bite, or want to discuss appropriate antibiotic therapy, contact us or schedule a visit for a same-week evaluation.