Amphotericin B potentiation of rifampicin as an antifungal agent against the yeast phase of Histoplasma capsulatum.

Rifampicin, at high concentrations, inhibited growth and RNA synthesis in the yeast phase of Histoplasma capsulatum. These effects were potentiated by low concentrations of amphotericin B. The combination of the two agents was fungicidal, whereas each alone, at much higher concentrations, was only fungistatic.