Erythromycin

Erythromycin

100mg/ml Suspension Oral Drops

125mg/5ml Suspension

200mg/5ml Suspension

250mg/5ml Suspension

250mg Tablet

500mg Tablet

DRUG CATEGORY:

Macrolide Antibacterial Drug

MECHANISM OF ACTION:

Erythromycin and other macrolides bind reversibly to the 50s sub units of the ribosome, resulting in blockage of the transpeptidation or translocation reactions in inhibition of protein synthesis, and hence inhibition of cell growth. Its action is predominantly bactericidal against the more sensitive strains.

PHARMACOKINETICS:

Erythromycin base is destroyed by stomach acid and must be administered with enteric coating. Stearates and esters are fairly acid-resistant and relatively well absorbed. The lauryl salt of propionyl ester of Erythromycin (Erythromycin estolate) is among the best-absorbed oral preparations. Oral doses of 2 g/d result in serum levels of up to 2μg/ml. Large amounts are lost in feces. Absorbed drug is distributed widely except to the brain and cerebrospinal fluid. It traverses the placenta and reaches the fetus.

Erythromycins are excreted largely in the bile, where levels may be 50 times higher than in the blood. A portion of the drug excreted into bile is reabsorbed from the intestines. Only 5% of the administered dose is excreted in the urine.

INDICATIONS:

Streptococcus pyogenes: Upper and lower respiratory tract, skin, and soft-tissue infections of mild to moderate severity.

Staphylococcus aureus: Acute infections of skin and soft tissue that are mild to moderately severe. Resistant organisms may emerge during treatment.

Streptococcus pneumoniae: Infections of the upper respiratory tract (e.g. otitis media, pharyngitis) and lower respiratory tract (e.g. pneumonia) of mild to moderate severity.

Mycoplasma pneumoniae: In the treatment of respiratory tract infections due to this organism.

Hemophilus influenzae: For upper respiratory tract infections of mild to moderate severity when used concomitantly with adequate doses of sulfonamides. The concomitant use of sulfonamides is necessary since not all strains of Hemophilus influenzae are susceptible to Erythromycin at the concentrations of the antibiotic achieved with usual therapeutic doses.

Chlamydia trachomatis: Erythromycin is indicated for treatment of the following infections caused by Chlamydia trachomatis: conjunctivitis of the new born, pneumonia of infancy and urogenital infections during pregnancy. When tetracyclines are contraindicated or not tolerated, Erythromycin is indicated for the treatment of uncomplicated urethral, endocervical, or rectal infections in adults due to Chlamydia trichomatis.

Treponema pallidum: Erythromycin is an alternate choice o treatment for primary syphilis in penicillin-allergic patients. In treatment of primary syphilis, spinal fluid examinations should be done before treatment and as part of follow-up after therapy.

Corynebacterium diphtheriae: As an adjunct to antitoxin, to prevent establishment of carriers, and to eradicate the organisms in carriers.

Corynebacterium minutissimum: In the treatment of erythema.

Estamoeba histolytica: in the treatment of intestinal amoebiasis only. Extra-enteric amoebiasis requires treatment with other agents.

Listeria monocytogenes: Infections due to this organism.

Bordetella pertussis: Erythromycin is effective in eliminating the organisms from the nasopharynx of infected individuals.

DOSAGE AND ADMINISTRATION:

Erythromycin may be given as the base or its salts or esters; doses are expressed in terms of the base. The usual oral dose is the equivalent of Erythromycin 1 to 2 g daily in 2 to 4 divided doses; for severe infections, this may be increased to up to 4g daily in divided doses. For children the dose is usually about 30 to 50mg per Kg body-weight daily although it may be doubled in severe infections; a recommended dose for children aged 2 to 8 years 1g daily in divided doses, and for infants and children up to 2 years of age, 500mg daily in divided doses.

In the patient who is unable to take Erythromycin by mouth and in severely ill patients in whom it is necessary to attain an immediate high blood concentration, Erythromycin maybe given intravenously in the form of one its more soluble salts such as gluceptate or the lactobionate, in doses equivalent to those by mouth.

CONTRAINDICATION:

Erythromycin is contraindicated in patients with known hypersensitivity to this antibiotic and in those with liver disorders.

PRECAUTION AND WARNING:

There have been a few reports of hepatic dysfunction, with or without jaundice, occurring in patients receiving oral Erythromycin products. All forms of Erythromycin should be used with care in patients with existing liver disease or hepatic impairment.

DRUG INTERACTION:

1. Erythromycin 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.
2. Concomitant administration of Erythromycin and Digoxin has been reported to result in elevated Digoxin serum levels.
3. There have been reports of increased anticoagulant effects when Erythromycin and oral anticoagulant were used concomitantly.
4. 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.
5. Erythromycin has been reported to decrease the clearance of triazolam and thus may increase the pharmacologic effect of triazolam.
6. The use of Erythromycin in patients concurrently taking drugs metabolized by the cytochrome P450 system may be associated with elevations in serum Erythromycin with carbamazepine, cycloporine, hexobarbital and phenytoin.
7. Serum concentrations of drugs metabolized by the cytochrome P450 system should be monitored closely in patients concurrently receiving Erythromycin.
8. Troleandomycin significantly alters the metabolism of terfenadine when taken concomitantly; therefore, observe caution when Erythromycin and terfenadine are used concurrently.
9. Patients receiving concomitant Lovastatin and Erythromycin should be carefully monitored: cases of rhabdomyolysis have been reported in seriously ill patients.
10. Concomitant use of CYP3A inhibitors like nitroimidazole antifungals can cause increased serum levels of Erythromcyin and probably increase the risk of cardiac arrhythmia.
11. Concurrent use of diltiazem or verapamil with Erythromycin should be avoided by persons at risk for heart irregularities or those with long QT manifestations.
12. Erythromycin may interfere with some diagnostic tests including measurement of urinary catecholamines and 17 – hydroxycorticosteroids.

ADVERSE DRUG REACTION:

The most frequent side effects of oral Erythromycin preparations are gastrointestinal and are dose-related. They include nausea, vomiting, abdominal pain, diarrhea and anorexia. Symptoms of hepatic dysfunction and/or abnormal liver function test results may occur. Pseudomembranous colitis has been rarely reported in association with Erythromycin therapy. There have been isolated reports of transient central nervous system side effects including confusion, hallucinations, seizures, and vertigo; however, a cause and effect relationship has not been established.

Occasional case reports of cardiac arrhythmias such as ventricular tachycardia have been documented in patients receiving Erythromycin therapy. There have been isolated reports of other cardiovascular symptoms such as chest pain, dizziness, and palpitations; however, a cause and effect relationship has not been established.

Allergic reactions ranging from urticaria and mild skin eruptions to anaphylaxis have occurred.

There have been isolated reports of reversible hearing loss occurring chiefly in patients with renal insufficiency and in patients receiving high doses of Erythromycin.

OVERDOSAGE:

In case of overdosage, Erythromycin should be discontinued. Overdosage should be handled with the prompt elimination of unabsorbed drug and all other appropriate measures. Erythromycin is not removed by peritoneal dialysis or hemodialysis.

STORAGE CONDITION:

Store at a temperatures not exceeding 30^oC.