1.ERYTHROMYCIN HISTORY
(How was Erythromycin discovered?)

Erythromycin is produced from a strain of the actinomyces Saccaropolyspora erythraea, formerly known as Streptomyces erythraeus.

Abelardo Aguilar, a Filipino scientist, sent some soil samples to his employer Eli Lilly in 1949. Eli Lilly's research team, led by J. M. McGuire, managed to isolate Erythromycin from the metabolic products of a strain of Streptomyces erythreus found in the samples. The product was subsequently launched in 1952.

Note: World-drugs.net sells generic version of Erythromycin

2.ERYTHROMYCIN FACTS

Erythromycin is a macrolide antibiotic, which has an antimicrobial spectrum similar or slightly wider to that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, Erythromycin has better coverage of atypical organisms, including mycoplasma.

Erythromycin is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea. Structurally, this macrocyclic compound contains a 14-membered lactone ring with ten asymmetric centers and two sugars, making it a compound very difficult to produce via synthetic methods. 

3.ABOUT ERYTHROMYCIN MEDICATION

What are antibiotics?

An antibiotic is a drug that destroys or slows the growth of bacteria. Antibiotics are one class of "antimicrobials", a larger group, which also includes anti-viral, anti-fungal, and anti-parasitic drugs. They are relatively harmless to the host, and therefore can be used to treat infections. The term originally described only those formulations derived from living organisms, in contradistinction to "chemotherapeutic agents", which were purely synthetic. Nowadays the term "antibiotic" is also applied also to synthetic antimicrobials, such as the sulfonamides.

Antibiotics are labeled as "magic bullets": drugs, which target the disease without harming the host. Antibiotics are not effective in viral, fungal and other nonbacterial infections, and individual Antibiotics vary widely in their effectiveness on various types of bacteria. Some specific Antibiotics target either gram-negative or gram-positive bacteria, and others are more wide-spectrum Antibiotics.

The effectiveness of individual Antibiotics depends on the location of the infection, the ability of the antibiotic to reach the site of infection, and the ability of the bacteria to resist or inactivate the antibiotic. Some Antibiotics actually kill the bacteria (bactericidal), whereas others merely prevent the bacteria from multiplying (bacteriostatic) so that the host's immune system can overcome them.

Classes of Antibiotics?

There are many ways to classify Antibiotics.

One such classification is by chemical structure:

Aminoglycosides

• Amikacin
• Dibekacin
• Gentamicin
• Kanamycin
• Neomycin
• Netilmicin
• Paromomycin
• Sisomycin
• Streptomycin
• Tobramycin

Beta-lactam ring antibiotics

Carbapenems

• Ertapenem
• Imipenem
• Meropenem

Cephalosporins and cephamycins

• Cephalexin
• Cefazolin
• Cefuroxime
• Cefadroxil
• Ceftazidime

Penicillins

• Amoxicillin

Monocyclic beta-lactams

Glycopeptide antibiotics

• Vancomycin
• Teicoplanin
• Ramoplanin
• Decaplanin

Oxazolidinones

• Linezolid
• Quinupristin/dalfopristin

Polyketides

Macrolides

• Erythromycin
• Azithromycin
• Clarithromycin
• Roxithromycin

Ketolides

• Telithromycin

Tetracyclines

• Doxycycline
• Oxytetracycline
• Chlortetracycline

Polymyxins

• Polymyxin B
• Colistin

Quinolones (fluoroquinolones)

• Nalidixic acid
• Ciprofloxacin (Cipro)
• Ofloxacin
• Norfloxacin (Norflox)
• Levofloxacin (Levaquin)
• Trovafloxacin (Trovan)

Streptogramins

Sulfonamides

• Prontosil

Other important antibiotics:

• Chloramphenicol
• Clindamycin
• Fusidic acid
• Trimethoprim

Another such classification is by their mechanism of action

Antibiotics, which interfere with cell-wall synthesis

Beta-lactams, including penicillins like amoxicillin and cephalosporins; mono-lactams, such as Imipenem; vancomycin, bacitracin

Antibiotics that interfere with bacterial protein synthesis

Antibiotics that bind to the 50S ribosomal unit

Lincosamides/lincosides including clindamycin and lincomycin; chloramphenicol, macrolides

Antibiotics, which interfere the 30S ribosomal unit

Tetracyclines; aminoglycosides including gentamicin

Drugs that inhibit folate synthesis

Sulfonamides and trimethoprim

Drugs that interfere with DNA synthesis

Metronidazole, quinolones, novobiocin

Drugs that interfere with RNA synthesis

Rifampin (rifampicin)

Drugs that interfere with cell membrane function

Polymyxin B, gramicidin

Antibiotics can also be classified by the organisms against which they are effective, and by the type of infection in which they are useful, which depends on the sensitivities of the organisms that most commonly cause the infection and the concentration of antibiotic obtainable in the affected tissue.

How does Erythromycin work?

Erythromycin is a type of medicine known as a macrolide antibiotic. Erythromycin is used to treat infections caused by bacteria.

Erythromycin binds reversibly to the 50S subunit. Erythromycin can inhibit elongation of the protein by the peptidyltransferase, the enzyme that forms peptide bonds between the amino acids.

Erythromycin works by preventing bacteria from producing proteins that are essential to them. Without these proteins the bacteria cannot grow, replicate and increase in numbers. Erythromycin doesn't directly kill the bacteria, but leaves them unable to increase in numbers. The remaining bacteria eventually die or are destroyed by the immune system. This treats the infection.

Stage 1.

Stage 2.

 

Stage 3.

 

Uses of Erythromycin

Erythromycin is a broad-spectrum antibiotic that is active against a wide variety of bacteria that cause a wide variety of infections.

Erythromycin may be used to treat infections of the upper or lower airways, skin or soft tissue, eyes or ears. Erythromycin may also be used to treat certain sexually transmitted infections, oral and dental infections, and to prevent infections in people who are at risk, for example due to surgery, trauma or burns.

Erythromycin is also used for treating inflammatory acne, as it is active against the bacteria associated with acne, Propionebacterium acnes. This is a common type of bacteria that feeds on sebum produced by the sebaceous glands in the skin. It produces waste products and fatty acids that irritate the sebaceous glands, making them inflamed and causing spots. By controlling bacterial numbers, Erythromycin brings the inflammation of the sebaceous glands under control, and allows the skin to heal. (Other Antibiotics may be preferred for acne however, as strains of the Propionebacterium that are resistant to Erythromycin are becoming widespread.)

To make sure the bacteria causing an infection are susceptible to Erythromycin your doctor may take a tissue sample, for example a swab from the throat or skin.

Erythromycin has a similar range of antibacterial activity to penicillin and so is also useful as an alternative to penicillin in people who are allergic to penicillins.

4.ERYTHROMYCIN EFFECTIVENESS
(When is Erythromycin best taken?)

Erythromycin dose is easily inactivated by gastric acids; therefore all orally administered Erythromycin doses are given as either enteric coated or as more stable salts or esters. Erythromycin dose is very rapidly absorbed, and diffused into most tissues and phagocytes. Due to the high concentration in phagocytes, Erythromycin is actively transported to the site of infection, where during active phagocytosis, large concentrations of Erythromycin are released.

Most of Erythromycin is metabolised by demethylation in the liver. Its main route elimination route is in the bile, and a small portion in the urine. Erythromycin's half-life is 1.5 hours. 

5.ERYTHROMYCIN EFFECTS ON SPECIAL POPULATION
(How do different people react to Erythromycin?)

There is no evidence that Erythromycin will harm a developing baby, but the possibility has not been completely ruled out. If you are pregnant or plan to become pregnant, inform your doctor immediately.

Erythromycin appears in breast milk and could affect a nursing infant. If Erythromycin is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment is finished.

6.ERYTHROMYCIN EFFECTS ON MEDICAL CONDITIONS
(How does Erythromycin affect your existing condition/ailment?)

Erythromycin should be used carefully in patients with abnormal heart rhythm, abnormal muscle weakness, decreased kidney function and decreased liver function.

Erythromycin should not be used by people with life long inherited blood diseases which can cause a variety of symptoms, including mental health problems (porphyrias).

7.OTHER/ALTERNATE USES OF ERYTHROMYCIN
(What else does Erythromycin treat?)

Erythromycin is used to treat some bacteria causing sexually transmitted diseases.

8.ADVERSE/SIDE EFFECTS of ERYTHROMYCIN
(What are the side effects of Erythromycin?)

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 hepatitis, hepatic dysfunction and/or abnormal liver function test results may occur.

Onset of pseudomembranous colitis symptoms may occur during or after antibiotic treatment.

Rarely, Erythromycin has been associated with the production of ventricular arrhythmias, including ventricular tachycardia and torsades de pointes, in individuals with prolonged QT intervals. 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 to anaphylaxis have occurred. Skin reactions ranging from mile eruptions to erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported rarely.

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

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.

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 interactions of Erythromycin with various oral anticoagulants 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 P450 system may be associated with elevations in serum levels of these other drugs. There have been reports of interactions of Erythromycin with carbamazepine, cyclosporine, tacrolimus, hexobarbital, phenytoin, alfentanil, cisapride, disopyramide, lovastatin, bromocriptine, valproate, terfenadine, and astemizole. Serum concentrations of drugs metabolized by the cytochrome P450 system should be monitored closely in patients concurrently receiving Erythromycin.

Erythromycin has been reported to significantly alter the metabolism of nonsedating antihistamines terfenadine and astemizole when taken concomitantly. Rare cases of serious cardiovascular adverse events, including electrocardiographic QT/QTc interval prolongation, cardiac arrest, torsades de pointes, and other ventricular arrhythmias have been observed. In addition, deaths have been reported rarely with concomitant administration of terfenadine and Erythromycin.

There have been postmarketing reports of drug interactions when Erythromycin is coadministered with cisapride, resulting in QT prolongation, cardiac arrythmias, ventricular tachycardia, ventricular fibrulation, and torsades de pointes, most like due to inhibition of hepatic metabolism of cisapride by Erythromycin. Fatalities have been reported.

Patients receiving concomitant lovastatin and Erythromycin should be carefully monitored; cases of rhabdomyolysis have been reported in seriously ill patients.