Leucopenia caused by two rifampicin preparations.

Leucopenia (= leucocyte count 3000 cells/microliters or less) caused by 2 rifampicin preparations used in daily tuberculosis chemotherapy was studied. In a group of 140 patients treated with Rimapen (Orion, Finland ), 11 cases (7.9%) of leucopenia were detected. In a group of 132 patients treated with Rimactan (Ciba-Geigy, Switzerland) one case of leucopenia (0.8%) occurred. The difference is statistically significant (p less than 0.01). The frequency of leucopenia in the Rimapen group was much higher than that reported in the literature. In cases of leucopenia caused by rifampicin the recommended measure is withdrawal of the drug or continued treatment under careful observation. If possible, rifampicin treatment should not be resumed after a pause, irrespective of its length.