ERYTHROMYCIN

General

Pronunciation:
eh-rith-roe-mye-sin

erythromycin base

Trade Name(s)

• E-Mycin
• Eryc 
• Ery-Tab
• PCE

erythromycin ethylsuccinate

Trade Name(s)

• E.E.S
• EryPed

erythromycin lactobionate

Trade Name(s)

• Erythrocin

erythromycin (topical)

Trade Name(s)

• Erygel

Ther. Class.

anti-infectives

Pharm. Class.

macrolides

See ophthalmic medications for ophthalmic use

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,
  • Syphilis or gonorrhea.
• Topical Acne.

Action

Suppresses protein synthesis at the level of the 50S bacterial ribosome.

Therapeutic Effect(s):

Bacteriostatic action against susceptible bacteria.

Spectrum:

• Active against many gram-positive cocci, including:

  • Streptococci,
  • Staphylococci.

• Gram-positive bacilli, including:

  • Clostridioides,
  • 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.

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 (plasma concentrations)

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity;
• Concurrent use of dihydroergotamine, ergotamine, lovastatin, pimozide, or simvastatin;
• Long QT syndrome;
• Hypokalemia;
• Hypomagnesemia;
• HR <50 bpm;
• Known alcohol intolerance (most topicals);
• Tartrazine sensitivity (some products contain tartrazine: FDC yellow dye #5);
• Pedi:  Products containing benzyl alcohol should be avoided in neonates.

Use Cautiously in:

• Renal impairment;
• Hepatic impairment;
• Myasthenia gravis (may worsen symptoms);
• OB:  May be used in pregnancy to treat chlamydial infections or syphilis;
• Geri:  ↑ risk of ototoxicity if parenteral dose >4 g/day and ↑ risk of QTc interval prolongation in older adults.

Adverse Reactions/Side Effects

CV: QT interval prolongation, TORSADES DE POINTES, VENTRICULAR ARRHYTHMIAS

Derm: rash

EENT: ototoxicity

GI: nausea, vomiting, abdominal pain, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD), cramping, diarrhea, hepatitis, infantile hypertrophic pyloric stenosis, pancreatitis (rare)

GU: interstitial nephritis

Local: phlebitis

Misc: HYPERSENSITIVITY REACTIONS (including anaphylaxis)

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

•  Pimozide  may ↑ levels and risk for serious arrhythmias; concurrent use contraindicated; similar effects may occur with  diltiazem,  verapamil,  ketoconazole,  itraconazole,  nefazodone, and  protease inhibitors ; concurrent use with pimozide contraindicated.
• May ↑ levels and risk for ergot toxicity of  ergotamine  and  dihydroergotamine ; concurrent use contraindicated.
•  Lovastatin  or  simvastatin  may ↑ risk of rhabdomyolysis; concurrent use contraindicated.
•  Amiodarone,  dofetilide, or  sotalol  may ↑ risk of torsades de pointes; avoid concurrent use.
• May ↑  verapamil  levels and risk for hypotension, bradycardia, and lactic acidosis.
• May ↑ levels and risk of toxicity of  sildenafil,  tadalafil, and  vardenafil ; use lower doses.
•  Rifabutin  or  rifampin  may ↓ levels and effectiveness.
• May ↑ levels and risk of toxicity of  alprazolam,  bromocriptine,  carbamazepine,  cyclosporine,  cilostazol,  diazepam,  disopyramide,  ergot alkaloids,  felodipine,  methylprednisolone,  midazolam,  quinidine,  rifabutin,  tacrolimus,  triazolam, or  vinblastine.
• May ↑ levels and risk of toxicity of  digoxin.
•  Theophylline  may ↓ levels and effectiveness.
• May ↑ levels and risk of toxicity of  colchicine ; use lower starting and maximum dose of colchicine.
• May ↑ levels and risk of toxicity of  theophylline ; ↓ theophylline dose.
• May ↑ levels of and risk of bleeding with  warfarin.

Route/Dosage

250 mg of erythromycin base = 400 mg of erythromycin ethylsuccinate.

Most Infections

PO (Adults): Base: 250 mg every 6 hr,  or  333 mg every 8 hr,  or  500 mg every 12 hr.  Ethylsuccinate: 400 mg every 6 hr  or  800 mg every 12 hr.

PO (Children  >1 mo): Base and ethylsuccinate: 30–50 mg/kg/day divided every 6–8 hr (max = 2 g/day as base or 3.2 g/day as ethylsuccinate).

PO (Neonates  ): Ethylsuccinate: 20–50 mg/kg/day divided every 6–12 hr.

IV (Adults): 250–500 mg (up to 1 g) every 6 hr.

IV (Children  >1 mo): 15–50 mg/kg/day divided every 6 hr (max = 4 g/day).

Acne

Topical (Adults and Children  >12 yr): 2% gel, solution, or pledgets twice daily.

Availability (generic available)

Erythromycin Base

Delayed-release capsules: 250 mg , 333 mg 

Delayed-release tablets: 250 mg, 333 mg, 500 mg

Erythromycin Ethylsuccinate

Oral suspension (fruit, cherry, orange, or banana flavor): 200 mg/5 mL, 400 mg/5 mL

Tablets: 400 mg

Erythromycin Lactobionate

Powder for injection (requires reconstitution and dilution): 500 mg/vial, 1 g 

Erythromycin Topical Preparations

Gel: 2%

Pledgets: 2%

Solution: 2%

In Combination with: benzoyl peroxide (Benzamycin). See combination drugs.

Assessment

• Assess for resolving infection (vital signs; appearance of wound, sputum, urine, and stool; WBC) during therapy.
• Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care provider promptly as a sign of CDAD. May begin up to several weeks following cessation of therapy.

Lab Test Considerations:

• Obtain specimens for culture and sensitivity before initiating therapy. 1st dose may be given before receiving results.

• Monitor liver function tests periodically in patients receiving high-dose, long-term therapy. May ↑ bilirubin, AST, ALT, and alkaline phosphatase.

  • Assess CBC to monitor for therapeutic response.
  • May cause false ↑ of urinary catecholamines.

Implementation

• PO Administer around the clock.  Erythromycin film-coated tablets (base)  are absorbed better on an empty stomach, >1 hr before or 2 hr after meals; may be taken with food if GI irritation occurs.  Enteric-coated erythromycin (base)  may be taken without regard to meals.  Erythromycin ethylsuccinate  is best absorbed when taken with meals. Take each dose with a full glass of water.
  • Use calibrated measuring device for liquid preparations. Shake well before using.
  •  DNC: Do not crush or chew delayed-release capsules or tablets; swallow whole.   Erythromycin base delayed-release capsules  may be opened and sprinkled on applesauce, jelly, or ice cream immediately before ingestion. Entire contents of the capsule should be taken.

• Topical Cleanse area before application. Wear gloves during application.

Patient/Family Teaching

• Explain purpose and side effects of erythromycin. Instruct patient to take medication around the clock and to finish the drug completely as directed, even if feeling better. Take missed doses as soon as remembered, with remaining doses evenly spaced throughout day. Advise patient to read  Patient Information  before starting therapy.
• Pedi:  Teach parents or caregivers to calculate and measure doses accurately. Reinforce importance of using measuring device supplied by pharmacy or with product, not household items.
• Instruct the patient to notify health care provider if symptoms do not improve.
• Advise patient to report the signs of superinfection (furry overgrowth on the tongue, vaginal itching or discharge, loose or foul-smelling stools) and allergy.
• Instruct patient to notify health care provider immediately if diarrhea, abdominal cramping, fever, or bloody stools occur and not to treat with antidiarrheals without consulting health care provider.
• Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care provider before taking other medications.
• May cause nausea, vomiting, diarrhea, or stomach cramps; notify health care provider if these effects persist or if severe abdominal pain, yellow discoloration of the skin or eyes, darkened urine, pale stools, or unusual tiredness develops. May cause infantile hypertrophic pyloric stenosis in infants; notify health care provider if vomiting and irritability occur.
• Rep:  Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

• Bacteriostatic action against susceptible bacteria.
• Resolution of the signs and symptoms of infection. Length of time for complete resolution depends on the organism and site of infection.
• Treatment of acne (topical).