Indications
IV, PO: Infections caused by susceptible organisms including:
Upper and lower respiratory tract infections,
Otitis media (with sulfonamides), Skin and skin structure
infections, Pertussis, Diphtheria, Erythrasma, Intestinal
amebiasis, Pelvic inflammatory disease, Nongonococcal
urethritis, Syphilis, Legionnaires’ disease,
Rheumatic fever. Useful when penicillin is the most appropriate
drug but cannot be used because of hypersensitivity,
including: Streptococcal infections, Treatment
of syphilis or gonorrhea. Topical: Treatment of
acne.
Action
Suppresses protein synthesis at the level of the 50S bacterial
ribosome. Therapeutic Effects: Bacteriostatic
action against susceptible bacteria. Spectrum:
Active against many gram-positive cocci, including:
Streptococci, Staphylococci. Gram-positive bacilli, including:
Clostridium, Corynebacterium. Several
gram-negative pathogens, notably: Neisseria, Legionella
pneumophila. Mycoplasma and Chlamydia are
also usually susceptible.
Pharmacokinetics
Absorption: Variable absorption from the duodenum
after oral administration (dependent on salt
form). Absorption of enteric-coated products is delayed.
Minimal absorption may follow topical or ophthalmic
use.
Distribution: Widely distributed. Minimal CNS penetration.
Crosses placenta; enters breast milk.
Protein Binding: 70–80%.
Metabolism and Excretion: Partially metabolized
by the liver, excreted mainly unchanged in the bile;
small amounts excreted unchanged in the urine.
Half-life: Neonates: 2.1 hr; Adults: 1.4–2 hr.
TIME/ACTION PROFILE (blood levels)
ROUTE ONSET PEAK DURATION
PO 1 hr 1–4 hr 6–12 hr
IV rapid end of infusion
6–12 hr
Contraindications/Precautions
Contraindicated in: Hypersensitivity; Concurrent
use of pimozide, ergotamine, dihydroergotamine, procainamide,
quinidine, dofetilide, amiodarone, or sotalol;
Long QT syndrome; Hypokalemia; Hypomagnesemia;
Heart rate 50 bpm; Known alcohol intolerance
(most topicals); Tartrazine sensitivity (some products
contain tartrazine—FDC yellow dye #5); Products containing
benzyl alcohol should be avoided in neonates.
Use Cautiously in: Liver/renal disease; OB: May be
used in pregnancy to treat chlamydial infections or
syphilis; Myasthenia gravis (may worsen symptoms);
Geri:qrisk of ototoxicity if parenteral dose 4 g/day,
qrisk of QTc interval prolongation.
Adverse Reactions/Side Effects
CNS: seizures (rare). EENT: ototoxicity. CV: TORSADE
DE POINTES, VENTRICULAR ARRHYTHMIAS, QT interval
prolongation. GI: CLOSTRIDIUM DIFFICILE-ASSOCIATED DIARRHEA
(CDAD), nausea, vomiting, abdominal pain,
cramping, diarrhea, hepatitis, infantile hypertrophic pyloric
stenosis, pancreatitis (rare). GU: interstitial nephritis.
Derm: rash. Local: phlebitis at IV site. Misc:
allergic reactions, superinfection.
Interactions
Drug-Drug: Concurrent use with pimozide mayq
levels and the risk for serious arrhythmias (concurrent
use contraindicated); similar effects may occur with
diltiazem, verapamil, ketoconazole, itraconazole,
nefazodone, and protease inhibitors; avoid
concurrent use. Mayqlevels of ergotamine and dihydroergotamine
and risk for acute ergot toxicity; concurrent
use contraindicated. Concurrent use with amiodarone,
dofetilide, or sotalol mayqrisk of
torsades de pointe; avoid concurrent use. Mayqverapamil
levels and the risk for hypotension, bradycardia,
and lactic acidosis.qblood levels and effects of sildenafil,
tadalafil, and vardenafil; use lower doses. Concurrent
rifabutin or rifampin maypeffect of erythromycin
andqrisk of adverse GI reactions.qlevels and
risk of toxicity from alfentanil, alprazolam, bromocriptine,
carbamazepine, cyclosporine, cilostazol,
diazepam, disopyramide, ergot alkaloids,
felodipine, methylprednisolone, midazolam,
quinidine, rifabutin, tacrolimus, triazolam, or
vinblastine. Mayqlevels of lovastatin and simvastatin
andqthe risk of myopathy/rhabdomyolysis. Mayq
serum digoxin levels. Theophylline maypblood levels.
Mayqcolchicine levels and the risk for toxicity;
use lower starting and maximum dose of colchicine.
Mayqtheophylline levels and the risk for toxicity;p
theophylline dose. Mayqwarfarin levels and the risk
for bleeding.
Route/Dosage
250 mg of erythromycin base or stearate400 mg of
erythromycin ethylsuccinate.
Most Infections
PO (Adults): Base, stearate—250 mg q 6 hr, or 333
mg q 8 hr, or 500 mg q 12 hr. Ethylsuccinate—400
mg q 6 hr or 800 mg q 12 hr.
PO (Children 1 mo): Base and ethylsuccinate—
30–50 mg/kg/day divided q 6–8 hr (maximum 2 g/
day as base or 3.2 g/day as ethylsuccinate). Stearate—
30–50 mg/kg/day divided q 6 hr (maximum 2 g/day).
PO (Neonates ): Ethylsuccinate—20–50 mg/kg/day
divided q 6–12 hr.
IV (Adults): 250–500 mg (up to 1 g) q 6 hr.
IV (Children 1mo): 15–50 mg/kg/day divided q 6
hr, maximum 4 g/day.
Acne
Topical (Adults and Children 12 yr): 2% ointment,
gel, solution, or pledgets twice daily.
Availability (generic available)
Erythromycin Base
Enteric-coated tablets: 250 mg, 333 mg, 500 mg.
Tablets with polymer-coated particles: 333 mg,
500 mg. Delayed-release capsules: 250 mg.
Erythromycin Ethylsuccinate
Tablets: 400 mg, 600 mg. Oral suspension (fruit
flavor, cherry): 200 mg/5 mL. Oral suspension
(orange, banana flavors): 400 mg/5 mL.
Erythromycin Lactobionate
Powder for injection: 500 mg, 1 g.
Erythromycin Stearate
Film-coated tablets: 250 mg, 500 mg.
Topical Preparations
Ointment: 2%. Gel: 2%. Solution: 2%. Pledgets:
2%. In combination with: benzoyl peroxide (Benzamycin).
See Appendix B.
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