Lymecycline
Indications
Lymecycline is used for:
Treatment of acne vulgaris, ear, nose and throat infections, acute exacerbation of chronic bronchitis, gastro-intestinal infection, soft tissue infection, brucella, pasteurella, pulmonary, genitourinary, ophth, gonococcal & resp infections, syphilis, Lyme disease, leptospirosis, cholera.
Adult Dose
Adults:
Chronic treatment of Acne
1 capsule daily.
Treatment should be continued for at least 8 weeks.
For other infections
1 capsule twice daily.
Child Dose
Child < 12 years: Safety & Efficacy not established.
Renal Dose
Administration
Contra Indications
Hypersensitivity to tetracyclines. Concurrent treatment w/ oral retinoids. Pregnancy & lactation. Childn <12 yr.
Precautions
Avoid exposure to direct sunlight & UV light. Renal & hepatic impairment.
Pregnancy-Lactation
Interactions
Oral retinoids (risk of intracranial HTN). Reduced absorption by Fe prep & antacids. Increased risk of haemorrhage w/ coumarin anticoagulants. Decreased digestive absorption w/ didanosine.
Adverse Effects
Side effects of Lymecycline :
Dental dyschromia &/or enamel hypoplasia especially in childn <12 yr. GI disturbances; hypersensitivity & photosensitivity reactions; rash, headache, diarrhea, colitis, nausea, vomiting, dermatitis, dysphasia, haemolytic anaemia, thrombocytopenia, neutropenia, eosinophilia & other hematologic disorders; extra-renal hyperazotemia.
Mechanism of Action
Tetracyclines provide bacteriostatic action at the available plasma and tissue concentrations and are effective against intracellular and extracellular organisms. Their mechanism of action is based on an inhibition of ribosomal protein synthesis. Tetracyclines block the access of the bacterial aminoacyl-tRNA to the mRNA-ribosome complex by binding to the 30S subunit of the ribosome, thus preventing the addition of amino acids to the growing peptide chain in protein synthesis. When given at therapeutically attainable concentrations their toxic effect is limited to the bacterial cells.
The exact mechanisms by which tetracyclines reduce lesions of acne vulgaris have not been fully elucidated; however, the effect appears to result in part from the antibacterial activity of the drugs. Following oral administration, the drugs inhibit the growth of susceptible organisms (mainly Propionibacterium acnes) on the surface of the skin and reduce the concentration 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. Free fatty acids are comedogenic and are believed to be a possible cause of the inflammatory lesions, e.g. papules, pustules, nodules, cysts, of acne.
However, other mechanisms also appear to be involved because clinical improvement of acne vulgaris with oral tetracycline therapy does not necessarily correspond with a reduction in the bacterial flora of the skin or a decrease in the free fatty acid content of sebum.