EROCIN 125MG/5ML POWDER

Indications

• Bacterial infections of the respiratory tract
• Skin and soft tissue infections
• Chlamydia infections
• Whooping cough (pertussis)
• Acne vulgaris (topical use)

Dosage

Adults: Refer to BNF for specific dosing guidelines. Commonly, erythromycin is administered orally or intravenously, with the dosage varying based on the

Mechanism of action

Erythromycin inhibits protein synthesis by binding to the 23S ribosomal RNA in the 50S subunit of bacterial ribosomes. This action disrupts the transpeptidation and translocation steps of protein synthesis, effectively halting the growth of susceptible bacteria. The binding occurs at or near the site that binds chloramphenicol, and erythromycin's strong affinity for bacterial ribosomes contributes to its broad-spectrum antibacterial activity.

Pharmacodynamics

As a bacteriostatic agent, erythromycin stops the growth of bacteria by inhibiting protein synthesis and translation, without affecting nucleic acid synthesis. It is known to be effective against many strains of various microorganisms. However, resistance can develop, and susceptibility testing is important prior to administration. Erythromycin has been associated with side effects such as pseudomembranous colitis and hepatotoxicity, which should be monitored during treatment.

Pharmacokinetics

Erythromycin is well-absorbed orally, but its absorption can be affected by food. It distributes widely in body tissues and fluids, with higher concentrations observed in tissues than in serum. The drug is metabolized in the liver, and its elimination half-life is approximately 1.5 hours. Erythromycin is excreted primarily in bile and urine, with both unchanged drug and metabolites found in these excretions. The pharmacokinetics can vary based on the formulation used (e.g., enteric-coated vs. non-coated).

Contra-indications

• Hypersensitivity to erythromycin or any of its components
• History of cholestatic jaundice or hepatic dysfunction associated with erythromycin therapy

Adverse effects

• Gastrointestinal disturbances such as nausea, vomiting, and diarrhea
• Hepatotoxicity, including elevated liver enzymes and jaundice
• Allergic reactions ranging from rash to anaphylaxis
• Pseudomembranous colitis
• QT prolongation leading to potential arrhythmias

Interactions

• Erythromycin may increase the plasma concentration of drugs metabolized by CYP3A4, such as statins, leading to an increased risk of myopathy
• Concurrent administration with theophylline can lead to increased theophylline levels, necessitating dose adjustments
• Erythromycin may enhance the effects of anticoagulants such as warfarin, increasing the risk of bleeding

Precautions

• Use with caution in patients with pre-existing liver disease or impaired hepatic function
• Monitor for signs of pseudomembranous colitis in patients experiencing diarrhea
• Assess potential for drug interactions with other medications metabolized by CYP enzymes
• Caution in patients with known cardiac arrhythmias due to the risk of QT prolongation

Pregnancy

Erythromycin is classified as a Category B drug. Animal studies have not shown any risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. Use only if clearly needed.

Breast-feeding

Erythromycin is excreted in breast milk. Caution is advised; use only if the benefits outweigh potential risks.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Tablets (250 mg, 500 mg)
• Oral suspension (125 mg/5 mL, 250 mg/5 mL)
• Injectable formulation (500 mg)

Mechanism of action

In order to replicate, bacteria require a specific process of protein synthesis, enabled by ribosomal proteins. Erythromycin acts by inhibition of protein synthesis by binding to the 23S ribosomal RNA molecule in the 50S subunit of ribosomes in susceptible bacterial organisms. It stops bacterial protein synthesis by inhibiting the transpeptidation/translocation step of protein synthesis and by inhibiting the assembly of the 50S ribosomal subunit. This results in the control of various bacterial infections. The strong affinity of macrolides, including erythromycin, for bacterial ribosomes, supports their broad‐spectrum antibacterial activities. Macrolide antibiotics are bacteriostatic agents that inhibit protein synthesis by binding reversibly to 50S ribosomal subunits of sensitive microorganisms, at or very near the site that binds chloramphenicol. Erythromycin does not inhibit peptide bond formation per se, but rather inhibits the translocation step wherein a newly synthesized peptidyl tRNA molecule moves from the acceptor site on the ribosome to the peptidyl donor site. Gram-positive bacteria accumulate about 100 times more erythromycin than do gram-negative bacteria. Cells are considerably more permeable to the un-ionized form of the drug, which probably explains the increased antimicrobial activity at alkaline pH. ... /Erythromycin/ inhibits the growth of susceptible organisms (principally Propionibacterium acnes) on the surface of the skin and reduces the concn of free fatty acids in sebum ... The reduction in free fatty acids in sebum may be an indirect result of the inhibition of lipase-producing organisms which convert triglycerides into free fatty acids or may be a direct result of interference with lipase production in these organisms. /In acne treatment regimens/ Although stromal-derived factor-1 (SDF-1) via its cognate receptor CXCR4 is assumed to play a critical role in migration of endothelial cells during new vessel formation after tissue injury, CXCR4 expression on endothelial cells is strictly regulated. Erythromycin (EM), a 14-membered ring macrolide, has an anti-inflammatory effect that may account for its clinical benefit in the treatment of chronic inflammatory diseases. However, the effects of EM on endothelial cells and especially their expression of CXCR4 have not been fully evaluated. In this study, we demonstrated that EM markedly induced CXCR4 surface expression on microvascular endothelial cells in vitro and lung capillary endothelial cells in vivo. This ability to induce CXCR4 surface expression on endothelial cells was restricted to 14-membered ring macrolides and was not observed in other antibiotics including a 16-membered ring macrolide, josamycin. Furthermore, this EM-induced expression of CXCR4 on endothelial cells was functionally significant as demonstrated by chemotaxis assays in vitro. These findings suggest that EM-induced CXCR4 surface expression on endothelial cells may promote migration of CXCR4-expressing endothelial cells into sites of tissue injury, which may be associated with the known anti-inflammatory activity of this macrolide.

Pharmacodynamics

Macrolides, such as erythromycin, stop bacterial growth by inhibiting protein synthesis and translation, treating bacterial infections. Erythromycin does not exert effects on nucleic acid synthesis. This drug has been shown to be active against most strains of the following microorganisms, effectively treating both in vitro and clinical infections. Despite this, it is important to perform bacterial susceptibility testing before administering this antibiotic, as resistance is a common issue that may affect treatment. **A note on antimicrobial resistance, pseudomembranous colitis, and hepatotoxicity** Many strains of Haemophilus influenzae are resistant to erythromycin alone but are found to be susceptible to erythromycin and sulfonamides used in combination. It is important to note that Staphylococci that are resistant to erythromycin may emerge during erythromycin and/or sulfonamide therapy. Pseudomembranous colitis has been reported with most antibacterial agents, including erythromycin, and may range in severity from mild to life-threatening. Therefore, the physician should consider this diagnosis in patients with diarrhea after the administration of antibacterial agents. Erythromycin can cause hepatic dysfunction, cholestatic jaundice, and abnormal liver transaminases, particularly when erythromycin estolate is administered.