Discontinuation of alprazolam after long-term treatment of 142 patients with panic-related disorders was examined in five study sites using a telephone interview. The majority (67%) of patients interviewed discontinued alprazolam for a period of at least 3 days after a gradual dosage reduction schedule over a 4-week period at the end of the long-term treatment study. A marked difference among the study sites in percentages of patients discontinuing therapy with alprazolam suggests that physician intervention played an important role in determining the ability of patients successfully to discontinue use of alprazolam: 90% and 95% of patients ceased therapy at two sites whereas only 21%, 38%, and 66% of patients discontinued therapy at the other three sites. The mean daily dosage for patients who continued using alprazolam decreased from 5.1 mg/day at the end of the long-term segment to 2.7 mg/day at the time of the poststudy interview. This decline indicates a lack of tolerance to the therapeutic effectiveness of alprazolam over an extended period of time.