Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Cefoxitin

Cefoxitin

Second-generation cephamycin (IV)

AnaerobesSSTIIntra-abdominalΞ²-lactam

Indication

Peritonitis (combo) β€’ pelvic infection (combo) β€’ some aspiration pneumonia adjunct β€’ surgical prophylaxis (selected)

At a glance

INDICATIONS (CORE USE)

Mixed aerobic/anaerobic infections (intra-abd, some SSTI) β€” **not** reliable for MRSA; **C. diff still occurs**.

ADULT DOSE (STANDARD)

1–2 g IV q6–8h; severe 2 g q6h

MAX DOSE

Adult ~12 g/day in extreme regimens β€” rare

Route

IV, IM

PEDIATRIC DOSE

80–160 mg/kg/day divided q6–8h (max per peds reference)

Do not miss

Must-not-miss safety points

Major warning

- Ξ²-lactam anaphylaxis - Not MRSA coverage β€” failure if staph is pathogen - Bacteroides resistance varies geographically β€” verify local Bacteroides susceptibility - Renal adjustment

Indications

USE IF: Intra-abdominal / polymicrobial infection as part of guideline regimen; some anaerobic-rich SSTI. AVOID IF: MRSA concern as sole beta-lactam; ESBL; when local Bacteroides resistance high.

Primary

  • Complicated intra-abdominal infection as combination component per guideline
  • Mixed aerobic/anaerobic pelvic infections (with additional agents per guideline)

Secondary

  • Diabetic foot infection combinations when anaerobes suspected (not monotherapy if MRSA risk)

Other

  • Surgical prophylaxis in institutions using cefoxitin (cefazolin often preferred)

Dosing

STANDARD (ADULT PO)

1–2 g IV q6–8h (2 g q6h many serious intra-abd regimens)

ADULT DOSE

2 g IV q6h many serious intra-abd regimens; 1 g q8h milder

PEDIATRIC DOSE

Weight-based divided doses.

MAX DOSE

High-dose protocols institution-specific.

Practical Note

Always pair with source control (drainage/surgery).

Warnings

Clinical warnings

  • **Ξ²-lactam allergy β€” immediate** (anaphylaxis, angioedema, bronchospasm, hypotension) β†’ **avoid** this agent; use non–β-lactam alternative
  • **Ξ²-lactam allergy β€” non-severe** (maculopapular rash without systemic anaphylaxis features) β†’ **caution**; risk/benefit + allergy/ID pathway; graded challenge or test dose **only** per protocol β€” do not dismiss automatically
  • **Neurotoxicity:** encephalopathy, confusion, myoclonus, seizures β€” **higher risk with CKD, elderly, dose accumulation** (notably cefepime, carbapenems, high-dose penicillins)
  • New CNS symptoms + renal impairment on IV Ξ²-lactam β†’ **hold dose**, check levels/exposure, rule out other causes
  • C. diff
  • Bleeding risk with anticoagulants (class nuance β€” monitor clinically)

Adverse effects

  • phlebitis
  • rash
  • diarrhea

Contraindications

  • Cephalosporin anaphylaxis when alternative mandated

Drug interactions

  • Aminoglycosides in synergy regimens β€” renal watch

Special populations

Pediatrics

80–160 mg/kg/day divided q6–8h (max per peds reference)

Pregnancy

Generally acceptable when indicated

Lactation

compatible broadly.

Renal impairment

Adjust interval/dose in CKD. **CrCl scaffold (FMBM β€” titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β‰₯50** β†’ standard interval (per Adult dosing card) - **CrCl 10–50** β†’ extend interval and/or reduce dose (often q12–24h or ↓ dose β€” **product-specific**) - **CrCl <10** β†’ maximal interval extension / dose reduction; **HD: redose post-dialysis** per protocol; AKI β†’ re-estimate CrCl; **neuro signs** β†’ hold/adjust

Hepatic impairment

No standard adjustment.

Elderly

Renal dosing; polypharmacy.

Administration

IV infusion.

Monitoring

  • Monitor: - ICU or CKD β†’ **creatinine daily** β†’ underdosing in AKI vs accumulation / **neurotoxicity** if not adjusted - New confusion / myoclonus / seizures + renal impairment on IV Ξ²-lactam β†’ **hold dose** β†’ evaluate encephalopathy - Serious GNR infection β†’ extended-infusion / pharmacy optimization per protocol - Anaerobic coverage adequacy if worsening clinically
  • Recheck: - Source control reassessment - No clinical improvement at 48–72h β†’ reassess diagnosis, resistance, source control, and drug interactions - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)

Overdose / toxicity

Clinical Picture

**Life-threatening (first):** **CNS toxicity** β€” seizures, encephalopathy, agitation, myoclonus, coma (**↑ CKD, elderly, accumulation**; cefepime, carbapenems, high-dose penicillins). **Allergic:** anaphylaxis / angioedema (separate pathway). **Secondary:** nausea/vomiting/diarrhea mainly with acute massive **oral** co-ingestion or local infusion reaction.

Immediate Actions

Stop Ξ²-lactam β†’ ABCs β†’ **seizure precautions**; benzos if seizures; check renal function / dose vs CrCl; anaphylaxis β†’ epinephrine + ACLS

Antidote

No specific antidote; treat complications (e.g. anaphylaxis β†’ epinephrine per ACLS)

Decontamination

Stop infusion; recent large PO load β†’ charcoal if protected airway + early presentation

Escalation

Status epilepticus, coma, refractory seizures β†’ **ICU**; **severe CNS toxicity or AKI with accumulation β†’ consider hemodialysis** for dialyzable agents β€” nephrology + pharmacy; persistent anaphylaxis β†’ ICU

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

Anaerobe-augmented spectrum vs many 2nd/3rd gens β€” still **not MRSA**. Resistance: regional Bacteroides.

Clinical pearls

Compare to piperacillin-tazobactam / carbapenem per severity and resistance. Stewardship: stop anaerobe coverage when no longer indicated. *Stewardship (all antimicrobials):* Empiric choice β†’ syndrome severity + **local antibiogram**; shortest effective course.

Stewardship & safety

  • MRSA gap
  • Source control
  • Renal adjust

Pharmacokinetics

Renal elimination; shorter half-life β€” q6h common for serious infection.

Mechanism of action

Cephamycin β€” Ξ²-lactamase stability vs some anaerobes + gram-negatives.

Common brand names

Saudi Arabia

Mefoxin, Cefoxitin

Global

(placeholder β€” verify local formulary)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Empiric choice β†’ tie to syndrome, severity, and local antibiogram β€” not habit.
  • IV β†’ PO step-down when oral bioavailability and susceptibility allow.
  • Do not use antibiotics for uncomplicated viral illness β€” stewardship.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling

Do not miss

  • Uncomplicated viral URI/bronchitis β†’ antibiotics rarely indicated
  • Narrow or stop when susceptibilities + clinical stability allow
  • Intra-abd without source control fails regardless of antibiotic.
  • C. diff.
  • MRSA gap
  • Source control
  • Renal adjust