The single-dose pharmacokinetics of the antifungal agent SCH 39304 (Schering-Plough Corp., Kenilworth, NJ) were assessed alone and in combination with antacid and cimetidine. On three separate occasions nine healthy men received a single oral 50 mg dose of SCH 39304 either alone, with 60 mL antacid, or with oral cimetidine 300 mg four times a day for 4 days. Concomitant antacid or cimetidine administration had no significant effect on any of the SCH 39304 pharmacokinetic parameters studied. The oral absorption of SCH 39304, as assessed by the area under the plasma concentration-time curve (AUC) and the amount of drug recovered unchanged in the urine, was not affected by either antacid or cimetidine. The AUC0-1 for the drug given alone was 80.5 +/- 15.8 micrograms.hr/mL, compared to 81.4 +/- 12.7 and 79.7 +/- 9.6 micrograms.hr/mL with concomitant antacid and cimetidine, respectively. The amount of drug excreted in the urine (Ae0-1) was 22.7 +/- 5.1, 24.2 +/- 9.2, and 23.6 +/- 7.6 mg when the drug was given alone, with antacid, and with cimetidine, respectively. Antacid coadministration delayed absorption as evidenced by an increase in the tmax in 7 out of 9 subjects, although this did not reach statistical significance (P = .082, Wilcoxon test). We conclude that concomitant antacid or cimetidine does not alter the oral absorption or pharmacokinetic disposition of single-dose SCH 39304.