2 DOSAGE AND ADMINISTRATION
2.1 Recommended Dosage
Administer XANAX XR orally once daily, preferably in the morning. Swallow tablets whole; do not divide, crush, or chew.
The recommended starting oral dosage for XANAX XR is 0.5 mg to 1 mg once daily. Depending on the response, the dosage may be adjusted at intervals of every 3 to 4 days in increments of no more than 1 mg daily. The recommended dosage range is 3 mg to 6 mg once daily.
Controlled trials of XANAX XR for the treatment of panic disorder included dosages in the range of 1 mg to 10 mg per day. Most patients showed a response in the dosage range of 3 mg to 6 mg per day. Occasional patients required as much as 10 mg per day.
The longer-term efficacy of XANAX XR has not been systematically evaluated. If XANAX XR is used for periods longer than 8 weeks, the healthcare provider should periodically reassess the usefulness of the drug for the individual patient.
After a period of extended freedom from panic attacks, a carefully supervised tapered discontinuation may be attempted, but there is evidence that this may often be difficult to accomplish without recurrence of symptoms and/or the manifestation of withdrawal phenomena [see Dosage and Administration (2.2), Warnings and Precautions (5.2)].
2.2 Discontinuation or Dosage Reduction of XANAX XR
Reduce the dosage by no more than 0.5 mg every three days. Some patients may benefit from an even more gradual discontinuation. Some patients may prove resistant to all discontinuation regimens.
In a controlled postmarketing discontinuation study of panic disorder patients which compared the recommended taper schedule with a slower taper schedule, no difference was observed between the groups in the proportion of patients who tapered to zero dose; however, the slower schedule was associated with a reduction in symptoms associated with a withdrawal syndrome.
2.3 Dosage Recommendations in Geriatric Patients
In geriatric patients, the recommended starting dosage of XANAX XR is 0.5 mg once daily. This may be gradually increased if needed and tolerated. Geriatric patients may be sensitive to the effects of benzodiazepines [see Use in Specific Populations (8.5), Clinical Pharmacology (12.3)].
2.4 Dosage Recommendations in Patients with Hepatic Impairment
In patients with hepatic impairment, the recommended starting dosage of XANAX XR is 0.5 mg once daily. This may be gradually increased if needed and tolerated [see Use in Specific Populations (8.6), Clinical Pharmacology (12.3)].
2.5 Dosage Modifications for Drug Interactions
XANAX XR should be reduced to half of the recommended dosage when a patient is started on ritonavir and XANAX XR together, or when ritonavir is added to a patient treated with XANAX XR. Increase XANAX XR dosage to the target dose after 10 to 14 days of dosing ritonavir and XANAX XR together. It is not necessary to reduce XANAX XR dosage in patients who have been taking ritonavir for more than 10 to 14 days.