Action And Clinical Pharmacology: Erythromycin exerts its antibacterial action by binding with the 50S ribosomal subunit of the organism, inhibiting peptide bond formation and protein synthesis within the cell. The activity is bacteriostatic or bactericidal depending on concentration. tag_IndicationsIndications
Indications And Clinical Uses: For the treatment of the following infections caused by susceptible strains of the designated microorganisms.
Upper Respiratory Tract Infections: Those of mild to moderate severity caused by S. pyogenes (group A beta hemolytic streptococci); S. pneumoniae (D. pneumoniae) and H. influenzae. Not all strains of H. influenzae are susceptible to erythromycin with usual therapeutic doses.
Lower Respiratory Tract Infections: Those of mild to moderate severity when caused by S. pyogenes (group A beta hemolytic streptococci); S. pneumoniae (D. pneumoniae) and M. pneumoniae (Eaton’s agent).
Pertussis (Whooping Cough): Caused by B. pertussis. Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them noninfectious. Clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals.
Diphtheria: As an adjunct to antitoxin in infections due to C. diphtheriae, to prevent establishment of carriers and to eradicate the organism in carriers.
Legionnaires’ Disease: Caused by L. pneumophila. Controlled clinical efficacy studies have not been conducted. In vitro and limited preliminary clinical data suggest that erythromycin can be effective in the treatment of Legionnaires’ disease.
Skin and Soft Tissue Infections: Those of mild to moderate severity when caused by S. pyogenes and S. aureus (resistance of staphylococci may emerge during treatment).
Erythrasma: In the treatment of infections due to C. minutissimum.
The treatment of acne vulgaris.
Sexually Transmitted Diseases: Primary Syphilis: Caused by T. pallidum. Erythromycin is an alternative choice of treatment for primary syphilis in patients allergic to the penicillins. Spinal fluid should be examined before treatment and as part of the follow-up after therapy.
Chlamydia Trachomatis Infection: The 1992 “Canadian Guidelines for the Treatment of Sexually Transmitted Diseases in Neonates, Children, Adolescents and Adults” recommends erythromycin for the treatment of the following infections when caused by Chlamydia trachomatis: In newborns and infants for conjunctivitis and pneumonia. Note: Topical therapy alone for conjunctivitis is not adequate. In pregnant women, nursing mothers, and in children under 9 years of age, for uncomplicated urethral, endocervical or rectal infection. In adolescents and adults, when tetracycline or doxycycline is contraindicated or not tolerated, for uncomplicated urethral, endocervical or rectal infection.
Specimens for bacteriologic culture should be obtained prior to therapy in order to isolate and identify the causative organisms and to determine their susceptibility to erythromycin. Therapy may be instituted before results of susceptibility studies are known; however, antibiotic treatment should be re-evaluated when the results become available or if the clinical response is not adequate.
Prophylaxis (Alpha-hemolytic Streptococci): For prophylaxis against bacterial endocarditis in patients hypersensitive to penicillin who have congenital heart disease or rheumatic or other acquired valvular heart disease when they undergo dental procedures and surgical procedures of the upper respiratory tract.
Contra-Indications: In patients with known hypersensitivity to erythromycin or with infections caused by microorganisms that are resistant to the drug.
Concurrent therapy with astemizole, terfenadine or cisapride (see Precautions, Drug Interactions).
Manufacturers’ Warnings In Clinical States: Erythromycin should be administered with caution to any patient who has demonstrated some form of allergy to drugs. If an allergic reaction to erythromycin occurs, administration of the drug should be discontinued. Serious hypersensitivity reactions may require epinephrine, antihistamines or corticosteroids.
There have been reports of hepatic dysfunction, with or without jaundice, occurring in patients receiving erythromycin products, particularly erythromycin estolate. If findings suggestive of significant hepatic dysfunction occur, therapy should be discontinued.
Pseudomembranous colitis has been occasionally reported to occur in association with erythromycin therapy. Therefore, it is important to consider its diagnosis in patients who develop diarrhea during treatment with erythromycin. Mild cases of colitis may respond to drug discontinuation alone. Moderate to severe cases should be managed with fluid, electrolyte and protein supplementation as indicated. If the colitis is not relieved by discontinuation of erythromycin administration or when it is severe, consideration should be given to the administration of vancomycin or other suitable therapy. Other possible causes of the colitis should also be considered.
Precautions: Prolonged or repeated use of erythromycin may result in an overgrowth of nonsusceptible bacteria or fungi and organisms initially sensitive to erythromycin. If superinfection occurs, erythromycin should be discontinued and appropriate therapy instituted.
Since erythromycin is principally excreted by the liver, caution should be exercised when administering the drug to patients with impaired hepatic function.
Drug Interactions: Theophylline: The concomitant administration of erythromycin and high doses of theophylline may be associated with increased serum theophylline levels and possible theophylline toxicity. The dose of theophylline may require reduction while patients are receiving erythromycin.
Carbamazepine: Erythromycin administration in patients receiving carbamazepine has been reported to cause increased serum levels of carbamazepine with subsequent development of signs of carbamazepine toxicity.
Digoxin/Phenytoin: Concomitant administration of erythromycin and digoxin or phenytoin has been reported to result in elevated serum levels of these agents, leading to toxicity in some patients.
Oral Anticoagulants: There have been reports of increased prothrombin time when erythromycin and oral anticoagulants were used concomitantly.
Ergotamine: There are reports that ischemic reactions may occur when erythromycin is given concurrently with ergotamine-containing drugs.
Cyclosporin: A rise in plasma cyclosporin levels has been reported during concomitant administration of erythromycin.
Lincomycin/Clindamycin/Chloramphenicol: Erythromycin should be used with caution if administered concomitantly with lincomycin, clindamycin, or chloramphenicol. In vitro experiments have demonstrated that binding sites for erythromycin, lincomycin, clindamycin and chloramphenicol overlap and competitive inhibition may occur.
Triazolam: Erythromycin has been reported to decrease the clearance of triazolam and thus may increase the pharmacologic effect of triazolam.
Alfentanil: The concomitant use of erythromycin with alfentanil can significantly inhibit the clearance of alfentanil and may increase the risk of prolonged or delayed respiratory depression.
Terfenadine: Terfenadine undergoes metabolism in the liver by a specific cytochrome P450 isoenzyme. This metabolic pathway may be impaired in patients who are taking erythromycin, an inhibitor of this isoenzyme. Interference with this enzyme can lead to elevated terfenadine plasma levels which may be associated with QT prolongation, and increased risk of ventricular tachyarrhythmias (such as torsades de pointes, ventricular tachycardia, and ventricular fibrillation) (see Contraindications).
Astemizole: Concomitant administration of astemizole with erythromycin is contraindicated because erythromycin is known to impair the Cytochrome P450 enzyme system which also influences astemizole metabolism. There have been two reports to date of syncope with torsades de pointes requiring hospitalization in patients taking astemizole with erythromycin. In each case the QT intervals were prolonged beyond 650 milliseconds at the time of the event; one patient also received ketoconazole and the other patient also had hypokalemia (see Contraindications).
Lovastatin: Patients receiving concomitant lovastatin and erythromycin should be carefully monitored; cases of rhabdomyolysis have been reported in seriously ill patients.
Cisapride: Rare cases of serious cardiovascular adverse events, including death, cardiac arrest, torsades de pointes, and other ventricular arrhythmias have been observed in patients taking cisapride concomitantly with macrolide antibiotics including erythromycin (see Contraindications).
The use of erythromycin in patients taking concurrent drugs which are metabolized by P450 (3A4) system may be associated with elevations in serum levels of these other drugs. There have been reports of interactions of erythromycin with cyclosporine, tacrolimus, hexobarbital and phenytoin. Serum concentrations of drug metabolized by the cytochrome P450 system should be monitored closely in patients concurrently receiving erythromycin.
Pregnancy: The safety of erythromycin for use during pregnancy has not been established. Erythromycin crosses the placental barrier.
Lactation: The safety of erythromycin for use during breast-feeding has not been established. Erythromycin is excreted in breast milk.
Children: The safety of erythromycin for use in neonates has not been established.
Information for the Patient: Eryc 250 and 333 mg capsules are not recommended for sprinkling, since the capsules are very full and some of the medication may be lost through spillage. If, however, the capsule is to be opened, care must be taken to open the capsule over food so as not to lose any of the pellets.
The pellets can be sprinkled on a small amount of pleasant tasting semi-solid foods such as applesauce, fruit jellies, ice cream, etc.
Hold the capsule with the clear end down. Gently twist off the cap to open. Sprinkle the entire contents of the capsule on a spoonful of applesauce, fruit jellies or ice cream, etc. The pellets should not be chewed or crushed. Patient should swallow the spoonful of applesauce, fruit jellies or ice cream. Patient should drink some water to make sure all the pellets are swallowed. If the pellets are accidentally spilled, start over with a new capsule.
Adverse Reactions: Gastrointestinal: abdominal cramping and discomfort. Nausea, vomiting and diarrhea are also observed, but less frequently. Pseudomembranous colitis has been occasionally reported to occur in association with erythromycin therapy (see Warnings).
Pancreatitis: Recently there has been a report of a case of erythromycin-induced pancreatitis following erythromycin overdose.
Allergic Reactions: Urticaria, mild skin eruptions and anaphylaxis have been reported.
Hepatotoxicity: There have been reports of hepatic dysfunction, with or without jaundice, occurring in patients receiving erythromycin products.
Miscellaneous: During prolonged or repeated therapy, there is a possibility of overgrowth of nonsusceptible bacteria or fungi and organisms initially sensitive to erythromycin (e.g., S. aureus, H. influenzae). If such infections occur, erythromycin should be discontinued and appropriate therapy instituted.
Occasionally there have been reports of reversible hearing loss occurring chiefly in patients with renal insufficiency and in patients receiving high doses of erythromycin.
There have been isolated reports of transient CNS side effects including confusion, hallucinations, seizures and vertigo; however, a cause and effect relationship has not been established.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: With doses of over 2 g per day, abdominal discomfort, nausea or diarrhea may occur. There has been a report of a case of erythromycin-induced pancreatitis following erythromycin overdose. There is no specific treatment for accidental overdosage. Erythromycin should be discontinued and gastric lavage should be considered; otherwise, treatment should be symptomatic. Erythromycin is not removed by peritoneal dialysis or hemodialysis.
Dosage And Administration: Blood levels obtained upon administration of enteric-coated erythromycin pellets in the presence of food are above minimum inhibitory concentrations (MICs) of most organisms for which erythromycin is indicated. However, maximum blood levels are obtained in the fasting state (at least 30 minutes and preferably 2 hours before or after a meal).
Adults: The usual dose is 250 mg every 6 hours or 333 mg every 8 hours. If twice-a-day dosage is desired, the recommended dose is 500 mg every 12 hours. Dosage may be increased up to 4 g/day, depending on the severity of infection. Twice-a-day dosing is not recommended when doses larger than 1 g daily are administered.
Children: Age, weight, and severity of the infection are important factors in determining the proper dosage. The usual dosage is 30 to 50 mg/kg/day in equally divided doses. For the treatment of more severe infections, this dosage may be doubled.
Upper and Lower Respiratory Tract and Skin and Soft Tissue Infections: A therapeutic dosage of oral erythromycin should be administered for at least 10 days. The recommended dosage is 1 g/day given in divided doses (2, 3 or 4 times a day), depending on the erythromycin preparation chosen. Depending on the severity of infection, doses up to 4 g may be considered; however, a single dose should not exceed 1 g.
Pertussis: Although optimal dosage and duration of therapy have not been established, doses of erythromycin utilized in reported clinical studies were 40 to 50 mg/kg/day, given in divided doses for 5 to 14 days.
Legionnaires’ Disease: Large doses of up to 4 g daily in divided doses are necessary for the treatment of known or suspected Legionella infections.
Acne Vulgaris: Initially, up to 1 g/day in divided doses. Depending on clinical response this may then be reduced to 333 to 500 mg/day as a maintenance dose. Extended administration of erythromycin requires regular evaluation, particularly of liver function.
Chlamydial Infections: The “Canadian Guidelines for the Treatment of Sexually Transmitted Diseases in Neonates, Children, Adolescents and Adults” recommends the following doses of erythromycin.
1. Conjunctivitis and pneumonia in newborns and infants: 40 mg/kg/day in 4 divided doses for at least 14 days. Note: Topical therapy alone for conjunctivitis is not adequate.
2. Uncomplicated urethral, endocervical or rectal infection: Children under 9 years of age; 40 mg/kg/day orally in 4 divided doses (up to a maximum of 500 mg q.i.d. for 7 days). Children over 9 years of age when tetracycline or doxycycline is contraindicated or not tolerated: 40 mg/kg/day orally in 4 divided doses (up to maximum of 500 mg q.i.d. for 7 days). Pregnant women and nursing mothers: 2 g orally/day in 3 or 4 equally divided doses for 7 days; or 1 g orally/day in 3 or 4 equally divided doses for 14 days if the larger dose is not tolerated. Adolescents and adults when tetracycline or doxycycline is contraindicated or not tolerated: 2 g/day in 3 or 4 equally divided doses for 7 days.
3. Complicated infection: The duration of treatment should be for at least 10 days.
As with all sexually transmitted diseases, follow-up cultures after termination of therapy are recommended in order to assess the microbiological response.
Primary Syphilis: 2 to 4 g/day given in divided doses either 2, 3 or 4 times-a-day depending on the erythromycin preparation chosen, over a period of 10 to 15 days.
Prophylaxis: For continuous prophylaxis against recurrence of streptococcal infections in adults with a history of rheumatic heart disease, the recommended dose is 250 mg twice a day.
For the prevention of bacterial endocarditis due to alpha-hemolytic streptococci in penicillin-allergic patients with valvular heart disease who are to undergo dental procedures or surgical procedures of the upper respiratory tract, the adult dose is 1 g 1 hour prior to the procedure and 500 mg 6 hours later. The pediatric prophylactic dose is 20 mg/kg (maximum 1 g) 1 hour before surgery, followed by 10 mg/kg (maximum 500 mg) 6 hours later.
See Precautions regarding alfentanil.
Availability And Storage: Eryc 250: Each 2-tone clear and orange opaque capsule, imprinted Eryc and P-D 696, contains: erythromycin base 250 mg as enteric-coated pellets. Nonmedicinal ingredients: cellulose acetate phthalate, diethyl phthalate, FD&C Yellow No. 6, lactose, methanol, methylene chloride, potassium phosphate monobasic and povidone; capsule shell: FD&C Yellow No. 6, gelatin and titanium dioxide. Energy: 0 kJ (0 kcal). Gluten-, lactose-, paraben-, sodium-, sulfite- and tartrazine-free. Bottles of 100 and 500.
Eryc 333: Each 2-tone clear and opaque yellow capsule, inscription on one end and Parke-Davis on the other, contains: erythromycin base 333 mg as enteric-coated pellets. Nonmedicinal ingredients: cellulose acetate phthalate, diethyl phthalate, FD&C Yellow No. 6, lactose, methanol, methylene chloride, potassium phosphate monobasic and povidone; capsule shell: D&C Yellow No. 10, D&C Red No. 33, gelatin and titanium dioxide. Energy: 0.5 kJ (0.13 kcal). Sodium 0.11 mg. Gluten-, paraben-, sulfite- and tartrazine-free. Bottles of 100 and 500.
Store at room temperature below 30°C. Protect from moisture and light. (Shown in Product Recognition Section)
ERYC® Parke-Davis Erythromycin Antibiotic