Erythrokem 250

Indications

• Bacterial infections of the respiratory tract
• Skin and soft tissue infections
• Chlamydia infections
• Treatment of syphilis in penicillin-allergic patients
• Acne vulgaris in conjunction with topical treatments
• Prophylaxis against bacterial endocarditis in certain patients

Dosage

Children: Refer to the BNF for Children for appropriate dosing based on the child's age, weight, and condition.

Adults: Refer to the BNF for specific dosing information based on the infection being treated and patient factors.

Mechanism of action

Erythromycin exerts its antibacterial effects by binding to the 50S subunit of the bacterial ribosome, inhibiting the translocation of peptidyl tRNA during protein synthesis. This disruption of protein synthesis leads to the inhibition of bacterial growth and replication.

Pharmacodynamics

Erythromycin is bacteriostatic at lower concentrations, meaning it inhibits the growth of bacteria without killing them. However, at higher concentrations, it can exhibit bactericidal activity. Its efficacy varies depending on the type of bacteria and the concentration of the drug. Erythromycin is particularly effective against streptococci, staphylococci, and certain strains of mycoplasma and chlamydia.

Pharmacokinetics

Erythromycin is well absorbed from the gastrointestinal tract, although food can affect its absorption. It is distributed widely in body tissues and fluids, with high concentrations found in the liver, lungs, and bile. The drug is metabolized in the liver and is primarily excreted in bile, with a small amount excreted in urine. The half-life of erythromycin ranges from 1 to 2 hours, and its pharmacokinetics can be influenced by hepatic function.

Contra-indications

• Hypersensitivity to erythromycin or any of its excipients.
• History of cholestatic jaundice or hepatic dysfunction associated with prior use of erythromycin.
• Concomitant use of certain drugs that are known to significantly prolong the QT interval.

Adverse effects

• Gastrointestinal disturbances such as nausea, vomiting, abdominal pain, and diarrhea.
• Cholestatic jaundice.
• Allergic reactions including rash, urticaria, and anaphylaxis.
• Hepatotoxicity.
• Prolongation of the QT interval and risk of torsades de pointes.

Interactions

• Increased plasma concentrations of drugs metabolized by CYP3A4 (e.g., statins, benzodiazepines) may occur.
• Concomitant use with other QT-prolonging agents may increase the risk of arrhythmias.
• Antacids containing aluminum or magnesium may reduce the absorption of erythromycin.

Precautions

• Use with caution in patients with pre-existing liver disease.
• Monitor for signs of hepatotoxicity and jaundice during treatment.
• Assess for potential drug interactions, particularly with medications metabolized by CYP3A4.

Pregnancy

Erythromycin is generally considered safe for use during pregnancy; however, it should be used only if clearly needed and prescribed by a healthcare professional.

Breast-feeding

Erythromycin is excreted in breast milk but is considered safe for use during breastfeeding; monitor for possible effects on the infant.

Storage

Store in a cool, dry place away from light. Liquid formulations should be refrigerated and used within the specified time frame after opening.

Formulations

• Oral tablets (various strengths)
• Oral suspension
• Topical ointment
• Injection solution