Erythromycin

General

• Type: Macrolide
• Dosage Forms: PO, IV, topical
• Common Trade Names:

Adult Dosing

• 250-500mg PO q6h

Pre-endoscopy

• 3mg/kg IV over 20-30min, 30-90min prior to endoscopy
  • Achieves endoscopy conditions equal to lavage

Pediatric Dosing

• Mild-moderate infections: 30-50 mg/kg/day PO divided q6-8hr
• Severe infection: 60-100 mg/kg/day PO divided q6-8hr

Special Populations

• Pregnancy Rating: B
• Lactation risk: AAP categorizes as compatible with breastfeeding
• Renal Dosing: No adjustment
• Hepatic Dosing: Use caution

Contraindications

• Allergy to class/drug
• QT prolongation

Adverse Reactions

Serious

• Torsades, ventricular dysrhythmias
• Pseudomembranous colitis
• Hypertrophic pyloric stenosis
• Seizures

Common

• nausea/vomiting
• diarrhea
• urticaria
• transaminitis
• urticarial rash

Pharmacology

• Half-life: 2 hours
• Metabolism: Liver
• Excretion: Bile/Renal
• Mechanism of Action: Binds to 50S ribosomal unit → inhibiting protein synthesis

Antibiotic Sensitivities

Group	Organism	Sensitivity
Gram Positive	Strep. Group A, B, C, G	I
	Strep. Pneumoniae	I
	Viridans strep	X1
	Strep. anginosus gp	X1
	Enterococcus faecalis	R
	Enterococcus faecium	R
	MSSA	I
	MRSA	R
	CA-MRSA	I
	Staph. Epidermidis	I
	C. jeikeium	R
	L. monocytogenes	S
Gram Negatives	N. gonorrhoeae	I
	N. meningitidis	X2
	Moraxella catarrhalis	I
	H. influenzae	I
	E. coli	R
	Klebsiella sp	R
	E. coli/Klebsiella ESBL+	R
	E coli/Klebsiella KPC+	R
	Enterobacter sp, AmpC neg	R
	Enterobacter sp, AmpC pos	R
	Serratia sp	X1
	Serratia marcescens	R
	Salmonella sp	R
	Shigella sp	R
	Proteus mirabilis	X1
	Proteus vulgaris	R
	Providencia sp.	X1
	Morganella sp.	X1
	Citrobacter freundii	X1
	Citrobacter diversus	X1
	Citrobacter sp.	X1
	Aeromonas sp	X1
	Acinetobacter sp.	R
	Pseudomonas aeruginosa	R
	Burkholderia cepacia	R
	Stenotrophomonas maltophilia	R
	Yersinia enterocolitica	R
	Francisella tularensis	X1
	Brucella sp.	R
	Legionella sp.	S
	Pasteurella multocida	X1
	Haemophilus ducreyi	S
	Vibrio vulnificus	X1
Misc	Chlamydophila sp	S
	Mycoplasm pneumoniae	S
	Rickettsia sp	I
	Mycobacterium avium	X1
Anaerobes	Actinomyces	S
	Bacteroides fragilis	R
	Prevotella melaninogenica	X1
	Clostridium difficile	X1
	Clostridium (not difficile)	I
	Fusobacterium necrophorum	R
	Peptostreptococcus sp.	I

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)