DESCRIPTION: - This comes from the class of antibiotics having a nucleus of four cyclic rings. All are obtained from soil actinomycetes. Doxycycline is primarily bacteriostatic; and is classified in the third group of tetracyclines. It is semisynthetic antibiotics with high potency, complete intestinal absorption, and high plasma protein binding, with a plasma t ½ of 18-24 hrs. It has minimal effect on intestinal flora and hence incidence of diarrhoea is low. It has least renal toxicity. And hence is a highly effective Broad Spectrum Antibiotic. It inhibits protein synthesis by binding to 30S ribosomes in susceptible organism. Subsequent to such binding, attachment of aminoacyl-tRNA to the mRNA- ribosome complex is interfered. As a result the peptide chain fails to grow. The sensitive organisms have an energy dependent active transport process, which concentrates tetracyclines intracellularly. In gram-negative bacteria tetracyclines diffuse through porin channels as well. It is more lipid soluble member & so enters by passive diffusion also (this is partly responsible for their higher potency). The carrier involved in active transport of tetracyclines is absent in the host cells. Moreover, protein-synthesizing apparatus of host cells is less sensitive to tetracyclines. These two factors are responsible for the selective toxicity of tetracyclines for the microbes.

INDICATIONS: -

§ It is used as a broad Spectrum Antibiotic.
§ It is used in Respiratory, genito-urinary, dental, and ophthalmic, ENT and gynecological infections. Venereal diseases.
§ It is used in Chlamydial infections, to treat atypical pneumonia due to Mycoplasma pneumoniae, cholera, Brucellosis.
§ It is used in the treatment of Plague: Doxycycline is highly effective in both bubonic and pneumonic plague.
§ It is used in Relapsing fever due to Borrelia recurrentis responds adequately.
§ It is used in Reckettsial infections like typhus rocky mountain spotted fever respond dramatically.
§ It may also be used in certain cases of UTI.
CONTRAINDICATION: - Hypersensitivity.
SPECIAL PRECAUTIONS: - impaired hepatic function, blood dyscrasias. Regular blood counts on long term therapy, Antacids, mineral supplements.
Paediatrics: Not recommended under 8 years. In older children reduced dose necessary.
Pregnancy: Contraindicated, may discolor teeth of the foetus.
Lactation: Contraindicated.
Elderly: No know problem.
Side effects: Tooth discoloration, enamel hypoplasia, reduced fibula growth rate. Avoid use in children below 8 years, unless no alternative drug.
Drug Interaction: Antacids, milk, calcium, magnesium and iron reduce absorption.
Presentation: - Available as 20 x 10 capsules in one Multicarton.