After experience with more than 34 million patients over 10 years, the safety of itraconazole and its potential drug-drug interactions are well known. In clinical trials, the average incidence of adverse events with a 1-week pulse regimen was 18% in pooled safety data (n = 2,867); only 2.2% of patients dropped out. In direct comparative trials, the incidence of mild and reversible adverse effects was comparable for itraconazole and terbinafine (31% and 28%, respectively) during treatment. The rate of permanent withdrawal because of adverse events was 3.6% for itraconazole and 7.5% for terbinafine (P < .05). Itraconazole was significantly better tolerated as evaluated by the investigator and patients. The analysis of the elderly subpopulation showed that patients 65 and older tolerated itraconazole pulse well, with only 20% experiencing mild and reversible side effects (total group). In direct comparative trials, itraconazole also produced fewer adverse effects than terbinafine (13% vs 32%, respectively). As newer oral antifungal agents gain widespread use, clinicians need to be aware of their potential drug-drug interactions and their possibly serious adverse events. However, pooled data from the 1-week itraconazole pulse regimen indicated a favorable safety profile, and a dose increase to 400 mg had no impact on safety.