Bioavailability of rifampicin, isoniazid and pyrazinamide from fixed-dose combination capsules

Int J Tuberc Lung Dis. 1998 Oct;2(10):824-30.


Setting: The absorption of rifampicin, isoniazid and pyrazinamide was tested after administration of each drug in free combinations and in a fixed-dose combination of the three drugs, known as Trifazid.

Objective: To examine the relative bioavailability of rifampicin, isoniazid and pyrazinamide after oral administration of the drugs given alone in comparison to that of the same drugs after administration of Trifazid.

Design: An open, randomized, cross-over study comprising 16 healthy volunteers.

Results: The pattern of absorption, plasma concentrations and pharmacokinetic parameters were very similar after administration of the drugs in free and fixed combinations.

Conclusion: The triple combination of antituberculosis drugs could replace the separate drugs in the treatment of tuberculosis.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Antibiotics, Antitubercular / administration & dosage
  • Antibiotics, Antitubercular / blood*
  • Biological Availability
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Drug Combinations
  • Female
  • Humans
  • Isoniazid / administration & dosage
  • Isoniazid / blood*
  • Male
  • Middle Aged
  • Pyrazinamide / administration & dosage
  • Pyrazinamide / blood*
  • Reference Values
  • Rifampin / administration & dosage
  • Rifampin / blood*


  • Antibiotics, Antitubercular
  • Drug Combinations
  • isoniazid, pyrazinamide, rifampin drug combination
  • Pyrazinamide
  • Isoniazid
  • Rifampin