Action And Clinical Pharmacology: Erythromycin exerts its antibacterial action by binding the 50S ribosomal subunit of susceptible bacteria and suppressing protein synthesis. Erythromycin is usually bacteriostatic but may be bactericidal in high concentrations or against highly susceptible organisms.
Indications And Clinical Uses: For the treatment of infections caused by susceptible strains of the designated microorganisms in the diseases listed below:
Upper respiratory tract infections of mild to moderate severity caused by S. pyogenes (Group A beta-hemolytic streptococci), S. pneumoniae and H. influenzae. Note: not all strains of H. influenzae are susceptible to erythromycin at the concentrations of the antibiotic achieved with usual therapeutic doses.
Lower respiratory tract infections of mild to moderate severity caused by S. pyogenes (Group A beta-hemolytic streptococci), S. pneumoniae and Mycoplasma pneumoniae.
Skin and soft tissue infections of mild to moderate severity caused by S. pyogenes and S. aureus. Note: Resistance of staphylococci may emerge during treatment.
Primary syphilis caused by T. pallidum. Erythromycin is an alternate choice of treatment for primary syphilis in patients allergic to penicillins. Spinal fluid examinations should be performed before treatment and as part of the post-therapy follow-up.
Diphtheria caused by C. diphtheriae. As an adjunct to antitoxin, to prevent the establishment of carriers, and to eradicate the organisms in carriers.
Erythrasma caused by C. minutissimum.
Pertussis caused by B. pertussis. Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them non-infectious. Some clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals.
Legionnaires’ disease caused by L. pneumophila. Although no controlled clinical efficacy studies have been conducted, in vitro and limited clinical data suggest that erythromycin can be effective in treating Legionnaires’ disease.
Chlamydial Infections: The 1988 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 children under 9 years of age, in pregnant women and in nursing mothers 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.
The treatment of acne vulgaris.
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: Erythromycin estolate is contraindicated in patients with a known history of sensitivity to this drug and in those with preexisting liver disease or dysfunction.
Concurrent therapy with astemizole or terfenadine (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. If findings suggestive of significant hepatic dysfunction occur, therapy with erythromycin products should be discontinued. Erythromycin has a greater propensity to cause hepatotoxicity.
Pseudomembranous colitis has been occasionally reported to occur in association with erythromycin therapy. Therefore, it is important to consider its diagnosis in patients administered erythromycin who develop diarrhea. 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 non-susceptible 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 erythromycin is administered to patients with impaired hepatic function.
Drug Interactions: Theophylline: Recent data from studies of erythromycin in patients reveal that its use in patients who are receiving high doses of theophylline may be associated with an increase in serum theophylline levels and potential theophylline toxicity. In case of theophylline toxicity and/or elevated serum theophylline levels, the dose of theophylline should be reduced while the patient is receiving concomitant erythromycin therapy.
Lincomycin/Clindamycin/Chloramphenicol: Erythromycin should be used with caution if administered concomitantly with these drugs. In vitro experiments have demonstrated that binding sites for erythromycin, lincomycin, clindamycin and chloramphenicol overlap and competitive inhibition may occur.
Carbamazepine/Digoxin/Phenytoin: Concomitant administration of erythromycin with carbamazepine, digoxin or phenytoin has been reported to result in elevated plasma levels of these agents, leading to toxicity in some patients.
Oral Anticoagulants: Published reports indicate that caution should be observed when erythromycin and oral anticoagulants are used concurrently since prothrombin time may be prolonged.
Triazolam: Erythromycin has been reported to decrease the clearance of triazolam and thus may increase the pharmacologic effect of triazolam.
Ergotamine: There are reports that ischemic reactions may occur when erythromycin is given concurrently with ergotamine-containing drugs.
Cyclosporine: There have been reports that there is a rise in plasma cyclosporine levels during concomitant administration of erythromycin.
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).
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.
Adverse Reactions: The most frequent adverse effects of erythromycin preparations are gastrointestinal (e.g., abdominal cramping and discomfort) and are dose related. Nausea, vomiting, and diarrhea occur infrequently with usual oral doses.
Adult erythromycin estolate administration has been associated with an infrequent occurrence of intrahepatic cholestasis.
Rarely, hepatic dysfunction, with or without jaundice, has occurred in association with erythromycin estolate administration. It may be accompanied by malaise, nausea, vomiting, abdominal colic, and fever. In some instances, severe abdominal pain may simulate the pain of biliary colic, pancreatitis, perforated ulcer, or an acute abdominal surgical problem. In other instances, clinical symptoms and liver function test results have resembled findings in extra-hepatic obstructive jaundice. If abnormalities occur, discontinue promptly. The syndrome seems to result from a form of sensitization, occurs chiefly in adults, and has been reversible when medication is discontinued.
In some cases, initial symptoms have developed after a few days of treatment, but generally they have followed 1 or 2 weeks of continuous therapy. If the above findings occur, discontinue erythromycin estolate promptly. After the drug is readministered to sensitive patients, symptoms reappear, usually within 48 hours.
Mild allergic reactions, such as urticaria and other skin rashes, have occurred. Serious allergic reactions, including anaphylaxis, have been reported rarely.
Symptoms And Treatment Of Overdose: Symptoms: Nausea, vomiting and diarrhea. Recently there has been a report of a case of erythromycin-induced pancreatitis following erythromycin overdose.
Treatment: General management may consist of supportive therapy.
Dosage And Administration: Administer orally. Infants and children 5 to 10 kg, 10 mg/kg every 6 hours, 10 to 25 kg, 125 mg every 6 hours. Adults and children over 25 kg, 250 mg every 6 hours or 500 mg every 12 hours. For severe infections, these dosages may be doubled.
If administration is desired on a twice a day schedule in either adults or children, 50% of the total daily dose may be given every 12 hours.
Streptococcal infections: In the treatment of Group A beta-hemolytic streptococcal infections, administer a therapeutic dosage of erythromycin for at least 10 days. In continuous prophylaxis of streptococcal infections in persons with a history of rheumatic heart disease, the dosage is 250 mg twice a day.
When erythromycin estolate is used prior to surgery to prevent endocarditis caused by alpha-hemolytic streptococci (viridans group), a recommended schedule for adults is 500 mg before the procedure and 250 mg every 8 hours for 4 doses afterward; for children, 30 to 50 mg/kg/day divided into 3 or 4 evenly spaced doses.
Primary syphilis: 20 to 30 g given in divided doses over a period of 10 to 15 days.
Amebic dysentery: 250 mg 4 times daily for 10 to 14 days for adults; 30 to 50 mg/kg/day in divided doses for 10 to 14 days for children.
Availability And Storage: Liquids: 125 mg: Each 5 mL contains: erythromycin estolate equivalent to 125 mg erythromycin base in an orange flavored vehicle. Nonmedicinal ingredients: butylparaben, cellulose and sodium CMC, citric acid, edetate calcium disodium, FD&C Yellow No. 6, methylparaben, orange 0.1 valencia, propylparaben, silicone, sodium chloride, sodium citrate, sodium lauryl sulfate, sucrose and water. Energy: 37.7 kJ (9.0 kcal)/5 mL. Sodium:
250 mg: Each 5 mL contains: erythromycin estolate equivalent to 250 mg erythromycin base in a cherry flavored vehicle. Nonmedicinal ingredients: amaranth, butylparaben, cellulose and sodium CMC, citric acid, edetate calcium disodium, FD&C Yellow No. 6, flavor imitation (cherry, cherry pit), imitation guarana liquid, methylparaben, propylparaben, silicone, sodium chloride, sodium citrate, sodium lauryl sulfate, sucrose and water. Energy: 29.7 kJ (7.1 kcal)/5 mL. Sodium:
Pulvules: Each No. 0 capsule with ivory, opaque body, imprinted with “Ilosone 250 mg”, and red, opaque cap, imprinted with “H09” contains: erythromycin estolate equivalent to erythromycin base 250 mg. Nonmedicinal ingredients: magnesium stearate, mineral oil, silica gel and talc; capsule shell and printing ink: ammonium hydroxide, benzyl alcohol, black iron oxide, butylparaben, edetate calcium disodium, ethyl alcohol, FD&C Red No. 3, FD&C Yellow No. 6, gelatin, iron oxide red, iron oxide yellow, isopropyl alcohol, methylparaben, n-butyl alcohol, propylene glycol, propylparaben, shellac, sodium lauryl sulfate, sodium propionate and titanium dioxide; may contain: dimethyl polysiloxane and potassium hydroxide. Sodium- and tartrazine-free. Bottles of 100.
ILOSONE® Lilly Erythromycin Estolate Antibiotic