Central Nervous System AgentsXanax XR (alprazolam) Extended-release Tablets
Manufacturer: Pharmacia & Upjohn
Drug Approval Classification: Original NDA (approval date: 1/17/03)
Panic disorder (DSM-IV) is characterized by recurrent unexpected panic attacks, ie, a discrete period of intense fear or discomfort in which 4 (or more) of the following symptoms develop abruptly and reach a peak within 10 minutes:
palpitations, pounding heart, or accelerated heart rate;
trembling or shaking;
sensations of shortness of breath or smothering;
feeling of choking;
chest pain or discomfort;
nausea or abdominal distress;
feeling dizzy, unsteady, lightheaded, or faint;
derealization (feelings of unreality) or depersonalization (being detached from oneself);
fear of losing control;
fear of dying;
paresthesias (numbness or tingling sensations);
chills or hot flushes.
The longer-term efficacy of Xanax XR has not been systematically evaluated. Thus, the physician who elects to use this drug for periods longer than 8 weeks should periodically reassess the usefulness of the drug for the individual patient.
Dosing: The recommended dose of Xanax XR is 1 tablet daily. Tablets should be taken intact; they should not be chewed, crushed, or broken.
The suggested total daily dose ranges from 3 to 6 mg/day. Dosage should be individualized for maximum beneficial effect.
Xanax XR is available in 0.5-mg, 1-mg, 2-mg, and 3-mg extended-release tablets.
Dose titration is recommended at intervals of 3 to 4 days in increments of no more than 1 mg/day. Dose reductions should be in increments of 0.5 mg every 3 days.
Patients who are currently being treated with divided doses of Xanax (immediate-release) tablets may be switched to Xanax XR tablets at the same total daily dose taken once daily.
Clinical Summary: Patients with panic disorder were enrolled in two 6-week, placebo-controlled studies. Efficacy was based on the change in multiple measures of panic attack frequency. The mean dose was 4.2 mg/day and 4.6 mg/day, respectively, in each study. Efficacy beyond 6 weeks has not been established.
Adverse Effects: Most frequent adverse events were similar to those seen with immediate-release alprazolam; they include sedation, somnolence, and memory impairment.
Pharmacokinetics: Xanax XR maintains a constant concentration for 5 to 11 hours after dosing. A high-fat meal given up to 2 hours before dosing with Xanax XR tablets increased the mean Cmax by about 25%. The effect of this meal on Tmax depended on the timing of the meal, with a reduction in Tmax by about one third for subjects eating immediately before dosing and an increase in Tmax by about one third for subjects eating 1 hour or more after dosing.
Medscape Pharmacists. 2003;4(1) © 2003 Medscape
Cite this: February 2003 - Medscape - Feb 20, 2003.