Ilosone/Ilosone DS

Erythromycin estolate.

Erythromycin inhibits protein synthesis without affecting nucleic acid synthesis.
Pharmacology: Pharmacokinetics: Orally administered erythromycin estolate is readily and reliably absorbed. Because of acid stability, serum levels are comparable whether the estolate is taken in the fasting state or after food. After a single 250-mg dose, blood concentrations average 0.29, 1.2 and 1.2 mg/L, respectively at 2, 4 and 6 hrs. Following a 500-mg dose, blood concentrations average 3, 1.9 and 0.7 mg/L, respectively at 2, 6 and 12 hrs.
After oral administration, serum antibiotic levels consist of erythromycin base and propionyl erythromycin ester. The propionyl ester continuously hydrolyzes to the base form of erythromycin to maintain an equilibrium ratio of approximately 20% base and 80% ester in the serum.
After absorption, erythromycin diffuses readily into most body fluids. In the absence of meningeal inflammation, low concentrations are normally achieved in the spinal fluid, but passage of the drug across the blood-brain barrier increases in meningitis. In the presence of normal hepatic function, erythromycin is concentrated in the liver and excreted in the bile. The effect of hepatic dysfunction of excretion of erythromycin by the liver into the bile is not known. After oral administration, <5% of the administered dose can be recovered as the active form in the urine.
Erythromycin crosses the placental barrier, but fetal plasma levels are low. The drug is excreted in human milk (see Use in pregnancy & lactation under Precautions).
Antagonism has been demonstrated between clindamycin and erythromycin.
Microbiology: Some strains of Haemophilus influenzae and staphylococci have demonstrated resistance to erythromycin. Some strains of H. influenzae that are resistant in vitro to erythromycin alone are susceptible to erythromycin and sulfonamides concomitantly.
Susceptibility Testing: If the Bauer-Kirby method of disc susceptibility testing is used, a 15-mcg erythromycin disc should give a zone diameter of at least 18 mm when tested against an erythromycin-susceptible organism.

Treatment of the following conditions in children and adults (culture and susceptibility testing should be done): Upper respiratory tract infections of mild to moderate severity caused by Streptococcus pyogenes, viridans group streptococci, Streptococcus pneumoniae or Haemophilus influenzae (when erythromycin is used concomitantly with adequate doses of sulfonamides, since not all strains of H. influenzae are susceptible at the erythromycin concentrations ordinarily achieved).
Lower respiratory tract infections of mild to moderate severity caused by S. pyogenes, S. pneumoniae, Mycoplasma pneumoniae or Legionella pneumophila.
Primary syphilis caused by Treponema pallidum. Erythromycin is an alternate choice of treatment for primary syphilis in penicillin-allergic patients. In primary syphilis, spinal fluid examination should be done before treatment and as part of follow up after therapy.
Diphtheriae: As an adjunct to antitoxin, to prevent establishment of carriers and to eradicate the organism in carriers.
Erythrasma: In the treatment of infections due to Corynebacterium minutissimum.
Intestinal amebiasis caused by Entamoeba histolytica. Extraenteric amebiasis requires treatment with other agents.
Infections due to Listeria monocytogenes.
Skin and soft tissue infections of mild to moderate severity caused by S. pyogenes or Staphylococcus aureus (resistant staphylococci may develop during treatment).
Pertussis Caused by Bordetella pertussis: Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them non-infectious. Some clinical studies suggests that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals.
Conjunctivitis of the newborn, pneumonia of infancy and urogenital infections during pregnancy caused by Chlamydia trachomatis (see Precautions). When tetracyclines are contraindicated or not tolerated, erythromycin is indicated for the treatment of adults with uncomplicated urethral, endocervical or rectal infections due to C. trachomatis.

Adults: Usual Dose: 250 mg every 6 hrs. This may be increased up to ≥4 g daily according to the severity of the infection.
Children: Age, weight and severity of the infection are important factors in determining the proper dosage. The usual regimen is 30-50 mg/kg/day in divided doses. For more severe infections, this dosage may be doubled.
If administration is desired on a twice-a-day schedule in either adults or children, ½ of the total daily dose may be given every 12 hrs. Twice-a-day dosing is not recommended with doses >1 g daily are administered.
Streptococcal Infections: For the treatment of streptococcal pharyngitis and tonsillitis, the usual dosage range is 20-50 mg/kg/day in divided doses (see table).

Click on icon to see table/diagram/image

In the treatment of group A β-hemolytic streptococcal infections, a therapeutic dosage of erythromycin should be administered 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.
For prophylaxis against bacterial endocarditis in penicillin allergic patients with congenital heart disease, rheumatic or other acquired valvular heart disease when undergoing dental procedures or surgical procedures of the upper respiratory tract. The dosage schedule for adults is 1 g (20 mg/kg for children) orally 1 hr before the procedure and then 500 mg (10 mg/kg for children) orally 6 hrs later.
Primary Syphilis: A regimen of erythromycin estolate 20 g in divided doses over a period of 10 days has been shown to be effective in the treatment of primary syphilis.
Dysenteric Amebiasis: Adults: 250 mg 4 times daily for 10-14 days. Children: 30-50 mg/kg/day in divided doses for 10-14 days.
Pertussis: Although optimum dosage and duration of treatment have not been established, dosage of erythromycin utilized in reported clinical studies was 40-50 mg/kg/day, given in divided doses for 5-14 days.
Legionnaire's Disease: Although optimum doses have not been established, doses utilized in reported clinical data were those recommended (1-4 g erythromycin estolate daily in divided doses).
Conjunctivitis of the Newborn Caused by C. trachomatis: Oral erythromycin suspension, 50 mg/kg/day in 4 divided doses for at least 2 weeks.
Pneumonia of Infancy Caused by C. trachomatis: Although the optimum duration of therapy has not been established, the recommended therapy is oral erythromycin suspension, 50 mg/kg/day in 4 divided doses for at least 3 weeks.
Urogenital Infections During Pregnancy Due to C. trachomatis: Although the optimum dose and duration of therapy have not been established, the suggested treatment is erythromycin, 500 mg orally 4 times a day for at least 7 days. For women who cannot tolerate this regimen, a decreased dose of 250 mg orally 4 times a day should be used for at least 14 days.
For adults with uncomplicated urethral, endocervical or rectal infections caused by C. trachomatis in whom tetracyclines are contraindicated or not tolerated, 500 mg orally 4 times a day for at least 7 days.

Symptoms: Nausea, vomiting, epigastric distress and diarrhea. The severity of the epigastric distress and the diarrhea are dose-related. Reversible mild acute pancreatitis has been reported. Hearing loss, with or without tinnitus and vertigo, may occur, especially in patients with renal or hepatic insufficiency.
Treatment: In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs and unusual drug kinetics in the patient.
Unless 5 times the normal single dose of erythromycin estolate has been ingested, gastrointestinal decontamination should not be necessary. An accidental ingestion of erythromycin should not be predicted to have minimal toxicity unless there is a good approximation of how much was ingested and unless only a single medication was involved.
Protect the patient's airway and support ventilation and perfusion. Meticulously monitor and maintain within acceptable limits, the patient's vital signs, blood gases, serum electrolytes and others. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which in many cases is more effective than emesis or lavage. Consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient's airway when employing gastric emptying or charcoal.
Forced diuresis, peritoneal dialysis, hemodialysis or charcoal hemoperfusion have not been established as beneficial for an overdose of erythromycin estolate.

Patients with known hypersensitivity to erythromycin. Patients taking terfenadine, astemizole, cisapride, pimozide, verapamil or diltiazem (see Interactions).
Patients with known history of sensitivity to erythromycin estolate and for those with preexisting liver disease.

Hepatic dysfunction with or without jaundice has occurred in adults, 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 an abdominal surgical emergency.
If the previous findings occur, discontinue erythromycin estolate promptly.
The administration of erythromycin estolate has been associated with the infrequent occurrence of cholestatic hepatitis. Laboratory findings have been characterized by abnormal hepatic function test values, peripheral eosinophilia and leukocytosis. Hepatic dysfunction with or without jaundice has occurred, chiefly in adults, in association with erythromycin estolate. Symptoms may include malaise, nausea, vomiting, abdominal cramp and fever. Jaundice may or may not be present. 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 results of liver function tests have resembled findings in extrahepatic obstructive jaundice. Initial symptoms have developed in some cases after a few days of treatment but generally have followed 1 or 2 weeks of continuous therapy. Symptoms reappear promptly, usually within 48 hrs after the drug is re-administered to sensitive patients. The symptoms seem to result from a form of sensitization, occur chiefly in adults and have been reversible when medication is discontinued.
Pseudomembranous colitis has been reported with nearly all antibacterial agents, including erythromycin estolate and may range in severity from mild to life-threatening. Therefore, it is important to consider its diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents. Mild cases of pseudomembranous colitis usually respond to discontinuation of the drug alone. In moderate to severe cases, appropriate measures should be taken.
Rhabdomyolysis with or without renal impairment has been reported in patients receiving erythromycin concomitantly with HMG-CoA reductase inhibitors eg, lovastatin and simvastatin. Therefore, patients receiving concomitant HMG-CoA reductase inhibitors and erythromycin should be very carefully monitored for creatinine kinase (CK) and serum transaminase levels.

Since erythromycin is excreted principally by the liver, caution should be exercised in administering the antibiotic to patients with impaired hepatic function. When indicated, incision and drainage or other surgical procedures should be performed in conjunction with antibiotic therapy.
Carcinogenicity & Mutagenicity: 2-year oral studies conducted in rats with erythromycin did not provide evidence of tumorigenicity or mutagenicity.
Use in pregnancy: Reproduction studies have been performed in rats, mice and rabbits, using erythromycin and its various salts and esters of doses several times the usual human dose. No evidence of impaired fertility or harm to the fetus that appeared to be related to erythromycin was reported in 3 studies. There are however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response this drug should be used during pregnancy only if clearly needed.
Labor and Delivery: The effect of erythromycin estolate on labor and delivery is unknown.
Use in lactation: Erythromycin is excreted in human milk. Caution should be exercised when erythromycin is administered to a nursing woman.
Use in children: Several reports of infantile hypertrophic pyloric stenosis have been reported in newborn infants receiving various erythromycin products, including erythromycin estolate. Erythromycin should be used cautiously in the first 3 months of life (see Indications and Dosage & Administration).

Use in pregnancy: Reproduction studies have been performed in rats, mice and rabbits, using erythromycin and its various salts and esters of doses several times the usual human dose. No evidence of impaired fertility or harm to the fetus that appeared to be related to erythromycin was reported in 3 studies. There are however, no adequate and well-controlled studies in pregnant women. Because animal reproductive studies are not always predictive of human response this drug should be used during pregnancy only if clearly needed.
Labor and Delivery: The effect of erythromycin estolate on labor and delivery is unknown.
Use in lactation: Erythromycin is excreted in human milk. Caution should be exercised when erythromycin is administered to a nursing woman.

The most frequent side effects of erythromycin preparations are gastrointestinal (eg, abdominal cramping and discomfort) and are dose-related. Nausea, vomiting and diarrhea occur frequently with usual oral doses. Onset of pseudomembranous colitis symptoms may occur during or after antibiotic treatment (see Warnings).
During prolonged or repeated therapy, there is a possibility of overgrowth of nonsusceptible bacteria or fungi. If such infections arise, the drug should be discontinued and appropriate therapy instituted.
Mild allergic reactions eg, urticaria and other skin rashes have occurred. Serious allergic reactions, including anaphylaxis, have been reported.
There have been isolated reports of hearing loss and/or tinnitus in patients receiving erythromycin. The ototoxic effect of the drug is usually reversible with drug discontinuance. However, in rare instances involving IV administration, the ototoxic effect has been irreversible. Ototoxic effects occur chiefly in patients with renal or hepatic insufficiency and in patients receiving high doses of erythromycin.
Very rarely erythromycin has been associated with QT prolongation and ventricular arrhythmias, including ventricular tachycardia and torsade des pointes.
Several reports of infantile hypertrophic pyloric stenosis have been reported in newborn infants receiving various erythromycin products, including erythromycin estolate. Erythromycin should be used cautiously in the first 3 months of life.

Erythromycin significantly alters the metabolism of terfenadine when taken concomitantly. Rare cases of serious cardiovascular adverse events, including death, cardiac arrest, Torsades de pointes and other ventricular arrhythmias, have been observed (see Contraindications).
Since probenecid inhibits tubular reabsorption of erythromycin in animals, it prolongs maintenance of plasma levels.
Lincomycin or clindamycin therapy should be avoided in treatment of infections due to erythromycin-resistant organisms.
Erythromycin use in patients who are receiving high doses of theophylline may be associated with 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.
Concomitant administration of erythromycin and digoxin has been reported to result in elevated digoxin serum levels.
There have been reports of increased anticoagulant effects when erythromycin and oral anticoagulants were used concomitantly. Increased anticoagulation effects due to this drug interaction may be more pronounced in the elderly.
Concurrent use of erythromycin and ergotamine or dihydroergotamine has been associated in some patients with acute ergot toxicity characterized by severe peripheral vasospasm and dysesthesia.
Erythromycin has been reported to decrease the clearance of triazolam and midazolam and thus may increase the pharmacologic effect of these benzodiazepines.
The use of erythromycin in patients concurrently taking drugs metabolized by the cytochrome P-450 system may be associated with elevations in serum concentrations of these other drugs. Elevated serum concentrations of the following drugs have been reported or may occur when administered concurrently with erythromycin: Carbamazepine, cyclosporine, hexobarbital, phenytoin, alfentanyl, disopyramide, quinidine; HMG-CoA reductase inhibitors eg, simvastatin and lovastatin, bromocriptine, PDE5 inhibitors eg, sildenafil, tadalafil and vardenafil. Serum concentrations, when available and appropriate, of these and other drugs metabolized by the cytochrome P-450 system should be monitored closely in patients concurrently receiving erythromycin and dosage adjustments made as needed. Elevated cisapride levels have been reported in patients receiving erythromycin and cisapride concomitantly. This may result in QT prolongation and lead to serious cardiac arrhythmias, including Torsades de pointes, ventricular tachycardia and ventricular fibrillation. Fatalities have been reported (see Contraindications).
Laboratory Tests: Erythromycin may interfere with AST (SGOT) determinations if a zone-fast violet B or diphenylhydrazine colorimetric determinations are used.
Erythromycin interferes with the fluorometric determination of urinary catecholamine.

Store at temperatures not exceeding 30°C.

Macrolides

J01FA01 - erythromycin ; Belongs to the class of macrolides. Used in the systemic treatment of infections.

Rx

Ilosone: Oral susp 125 mg/5 mL (orange-flavored) x 60 mL. Oral drops 100 mg/mL (orange-flavored) x 10 mL.
Ilosone DS: Oral susp 250 mg/5 mL (cherry-flavored) x 60 mL.