Friday, April 15, 2011

Rifampin

It is also called as rifampicin. It is a semisynthetic derivative of rifamycin which is an antibiotic produced by a bacterium Streptomyces mediterranei.


Rifampin is a blend of rifamycin and piperazine.
Mechanism of action:
Rifampin is bactericidal for mycobacteria. Human RNA polymerase is not affected by rifampin.

Pharmacokinetics:
It is well absorbed orally.

It readily penetrates most of the tissues and phagocytic cells and that is why it is widely distributed in body fluids and tissues.

It is excreted through liver into the bile where it undergoes enterohepatic recirculation.

Deacylated metabolite is excreted in feces and small amount is excreted through urine.

Therapeutic uses:
It is used in mycobacterial infections such as tuberculosis and leprosy. It is also used in prophylaxis in contact of children with Haemophilus influenzae type b disease.

In combination therapy, it is also used for serious Staphylococcal infections.

Dosage:
Its usual dose is 600mg/day with isoniazid, ethambutol or other anti-tuberculous drugs.

Adverse effects:
It produces harmless orange colour to urine, sweat and tears. It may cause rashes, light chain proteinuria, thrombocytopenia and nephritis.

Resistance:
Resistance is found to be due to alteration in the genetic material of bacteria DNA dependent RNA polymerase.
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