[Clinico-pharmacokinetic interactions of rifampicin, pyrazinamide and isoniazide]

We investigated the pharmacokinetic interaction of RMP (administered from the first day of treatment onwards), PZA (given from the second day onwards), and INH (day 17 onwards) in ten, previously untreated patients with pulmonary tuberculosis (five slow acetylators and five fast acetylators). In the case of the slow acetylators, higher INH and acetylhydrazine concentrations were measured than in the fast acetylators. RMP revealed the well-known autoinduction of its metabolism. During the course of continuing treatment, the PZA levels increased. No increased incidence of hepatoxic reactions was to be seen.