Cefmenoxime

General

• Type: 3rd generation Cephalosporin
• Dosage Forms: powder for injection
• Dosage Strengths: 0.5g, 1g
• Routes of Administration: IV, IM
• Common Trade Names: Cefmax, Bestcall

Adult Dosing

General

• Standard: 500mg-1g IM/IV q12h
• Severe: 2-4g/day IM/IV divided q6-8h
• Max: 4g/day

Pneumonia / Respiratory Tract Infections

• 1-2g IM/IV divided q12h

UTI, Complicated and Uncomplicated

• 0.5-1g IM/IV q12h

Intra-abdominal / Gynecological Infections

• 1g IM/IV q8h
• Provides better anaerobic coverage than many other cephalosporins (similar to cefoxitin/cefotetan)

Gonorrhea

• 1g IM x 1

Pediatric Dosing

General

• 40-100mg/kg/day IM/IV divided q6-12h
• Severe infections: Up to 200mg/kg/day divided q6h
• Max: 4g/day

Meningitis

• 200mg/kg/day IM/IV divided q6h

Special Populations

• Pregnancy: B
• Lactation: Excreted in breast milk; withdraw drug or stop nursing
• Renal
  • Adult
    • CrCl 10-30: 500mg-1g q24h
    • CrCl <10: 500mg-1g q48h
    • Hemodialysis: Administer dose after dialysis
  • Pediatric
    • Renal impairment requires adjustment; defined data limited, generally widen interval based on GFR.
• Hepatic
  • No specific adjustment defined

Contraindications

• Allergy to class/drug (Cephalosporins)
• History of anaphylactic shock

Adverse Reactions

Serious

• Anaphylaxis
• Stevens-Johnson Syndrome
• Clostridium difficile
• Hypoprothrombinemia (Bleeding tendency)
  • Contains N-methylthiotetrazole (MTT) side chain which inhibits Vitamin K reduction.
• Disulfiram-like reaction (with alcohol intake)

Common

• Diarrhea
• Rash
• Nausea
• Injection site pain/phlebitis
• Eosinophilia
• Transaminitis

Pharmacology

• Half-life: ~1 hour (prolonged in renal failure)
• Metabolism: Minimal; N-methylthiotetrazole (MTT) side chain is dissociated.
• Excretion: Urine
• Mechanism of Action: Bactericidal; inhibits cell wall mucopeptide synthesis.
• Chemical Note: Possesses MTT side chain (associated with bleeding risk and alcohol intolerance).

Antibiotic Sensitivities

Group	Organism	Sensitivity
Gram Positive	Strep. Group A, B, C, G	S
	Strep. Pneumoniae	S
	Viridans strep	S
	Strep. anginosus gp	X1
	Enterococcus faecalis	R
	Enterococcus faecium	R
	MSSA	S
	MRSA	R
	CA-MRSA	R
	Staph. Epidermidis	I
	C. jeikeium	R
	L. monocytogenes	R
Gram Negatives	N. gonorrhoeae	S
	N. meningitidis	S
	Moraxella catarrhalis	S
	H. influenzae	S
	E. coli	S
	Klebsiella sp	S
	E. coli/Klebsiella ESBL+	R
	E coli/Klebsiella KPC+	R
	Enterobacter sp, AmpC neg	I
	Enterobacter sp, AmpC pos	R
	Serratia sp	S
	Serratia marcescens	S
	Salmonella sp	S
	Shigella sp	S
	Proteus mirabilis	S
	Proteus vulgaris	S
	Providencia sp.	S
	Morganella sp.	S
	Citrobacter freundii	I
	Citrobacter diversus	S
	Citrobacter sp.	I
	Aeromonas sp	S
	Acinetobacter sp.	R
	Pseudomonas aeruginosa	R
	Burkholderia cepacia	R
	Stenotrophomonas maltophilia	R
	Yersinia enterocolitica	S
	Francisella tularensis	X1
	Brucella sp.	X1
	Legionella sp.	R
	Pasteurella multocida	S
	Haemophilus ducreyi	S
	Vibrio vulnificus	S
Misc	Chlamydophila sp	R
	Mycoplasm pneumoniae	R
	Rickettsia sp	R
	Mycobacterium avium	R
Anaerobes	Actinomyces	S
	Bacteroides fragilis	I
	Prevotella melaninogenica	S
	Clostridium difficile	X1
	Clostridium (not difficile)	S
	Fusobacterium necrophorum	S
	Peptostreptococcus sp.	S

Key

• S susceptible/sensitive (usually)
• I intermediate (variably susceptible/resistant)
• R resistant (or not effective clinically)
• S+ synergistic with cell wall antibiotics
• U sensitive for UTI only (non systemic infection)
• X1 no data
• X2 active in vitro, but not used clinically
• X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
• X4 active in vitro, but not clinically effective for strep pneumonia

See Also

• Antibiotics (Main)