What is the recommended dosing, contraindications, and renal dose adjustments for cefixime tablets?

Cefixime Tablets: Dosing, Contraindications, and Renal Adjustments

Recommended Dosing

For adults, cefixime is dosed at 400 mg orally once daily, which can be administered without regard to food. 1

Adult Dosing Specifics

• Standard dose: 400 mg orally once daily 1
• Uncomplicated gonorrhea (cervical/urethral): 400 mg as a single oral dose 2, 1
• Administration: May be taken with or without meals, as food does not affect absorption 3
• Duration for streptococcal infections: Minimum 10 days of therapy required for Streptococcus pyogenes infections 1

Pediatric Dosing (≥6 months)

• Standard dose: 8 mg/kg/day of oral suspension 1
• Administration options: Single daily dose OR divided into 4 mg/kg every 12 hours 1
• Important caveat: Suspension formulation must be used for otitis media, as it achieves higher peak blood levels than tablets at equivalent doses 1
• Safety note: Efficacy and safety not established in infants <6 months 1

Contraindications

Cefixime is contraindicated in patients with known hypersensitivity to cefixime or other cephalosporins. 1

Critical Safety Warnings

• Hypersensitivity reactions: Shock and fatalities have been reported; discontinue immediately if allergic reaction occurs 1
• Cross-reactivity: Patients with penicillin allergy may have cross-sensitivity to cephalosporins 1
• Clostridioides difficile-associated diarrhea: Evaluate if diarrhea develops during or after treatment 1

Pregnancy and Lactation

• Pregnancy: Use only if clearly needed (no adequate controlled studies) 1
• Breastfeeding: Consider temporarily discontinuing nursing during treatment, as <1% of dose penetrates breast milk 1, 4

Renal Dose Adjustments

Dose adjustment is required when creatinine clearance falls below 60 mL/min. 1

Specific Renal Dosing Guidelines

For creatinine clearance ≥60 mL/min: Normal dose (400 mg daily) 1

For creatinine clearance 21-59 mL/min:

• Reduce to 260 mg daily (13 mL of 200 mg/5 mL suspension) 1
• Alternatively: 130 mg daily (6.5 mL of 200 mg/5 mL suspension) 1

For creatinine clearance ≤20 mL/min OR continuous peritoneal dialysis:

• Reduce to 172 mg daily (8.6 mL of 100 mg/5 mL suspension OR 4.4 mL of 200 mg/5 mL suspension) 1

For hemodialysis patients:

• Use same dosing as creatinine clearance ≤20 mL/min 1
• No supplemental dose needed after dialysis, as neither hemodialysis nor peritoneal dialysis removes significant amounts of drug 1, 5, 3

Pharmacokinetic Rationale

• Elimination half-life increases from 3-4 hours in normal renal function to 12-14 hours when creatinine clearance <20 mL/min 5, 3, 6
• Renal clearance accounts for 40% of total drug elimination, with hepatic clearance accounting for 60% 3
• Protein binding decreases with worsening renal function, becoming statistically significant when creatinine clearance <20 mL/min 5
• Volume of distribution remains stable across all degrees of renal impairment 5

Clinical Efficacy Context

Cefixime achieves 97.1-97.4% cure rates for uncomplicated urogenital and anorectal gonococcal infections, though this is lower than ceftriaxone's 99.1% cure rate due to lower and less sustained bactericidal levels 2

Spectrum of Activity

• Effective against common respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae (including β-lactamase-producing strains), and Moraxella catarrhalis 7, 8
• Urinary concentrations exceed MICs for most urinary tract pathogens for up to 24 hours post-dose, even in severe renal insufficiency 5

Important Limitations

• Not recommended as first-line for gonorrhea in current practice due to widespread fluoroquinolone resistance and preference for ceftriaxone 9
• Absolute bioavailability is only 50% compared to intravenous administration 3
• No accumulation occurs with repeated once-daily or twice-daily dosing over 15 days 10

Common Pitfalls to Avoid

• Do not use tablets/capsules for otitis media—suspension required for adequate blood levels 1
• Do not give supplemental doses after dialysis—dialysis removes insignificant amounts of drug 1, 5
• Do not adjust dose in cirrhotic patients despite doubled elimination half-life (~6.5 hours), as no dosage modification is needed 3
• Ensure concentration is specified when prescribing suspension in milliliters, as two concentrations exist (100 mg/5 mL and 200 mg/5 mL) 1