DOSAGE AND ADMINISTRATION
Usual Dose
SEROQUEL XR should be administered once daily, preferably in the evening. The recommended initial dose is 300 mg/day. Patients should be titrated within a dose range of 400 – 800 mg/day depending on the response and tolerance of the individual patient [ see Clinical Studies ]. Dose increases can be made at intervals as short as 1 day and in increments of up to 300 mg/day. The safety of doses above 800 mg/day has not been evaluated in clinical trials.
SEROQUEL XR tablets should be swallowed whole and not split, chewed or crushed.
It is recommended that SEROQUEL XR be taken without food or with a light meal (approximately 300 calories) [ see Clinical Pharmacology ].
Dosing in Special Populations
Consideration should be given to a slower rate of dose titration and a lower target dose in the elderly and in patients who are debilitated or who have a predisposition to hypotensive reactions [see Use in Specific Populations (8.5, 8.7) and Clinical Pharmacology ]. When indicated, dose escalation should be performed with caution in these patients.
For those patients who require less than 200 mg per dose of SEROQUEL XR during the initial titration, use the immediate release formulation.
Elderly patients should be started on SEROQUEL immediate release formulation 25 mg/day and the dose can be increased in increments of 25–50 mg/day depending on the response and tolerance of the individual patient. When an effective dose has been reached, the patient may be switched to SEROQUEL XR at an equivalent total daily dose [ see Switching Patients from SEROQUEL Tablets to SEROQUEL XR Tablets ].
Patients with hepatic impairment should be started on SEROQUEL immediate release formulation 25 mg/day. The dose can be increased daily in increments of 25–50 mg/day to an effective dose, depending on the clinical response and tolerance of the patient. When an effective dose has been reached, the patient may be switched to SEROQUEL XR at an equivalent total daily dose [ see Switching Patients from SEROQUEL Tablets to SEROQUEL XR Tablets ].
The elimination of quetiapine was enhanced in the presence of phenytoin. Higher maintenance doses of quetiapine may be required when it is coadministered with phenytoin and other enzyme inducers such as carbamazepine and phenobarbital [See Drug Interactions ].
Maintenance Treatment
While there is no body of evidence available to specifically address how long the patient treated with SEROQUEL XR should remain on it, it is recommended that responding patients be continued on SEROQUEL XR, but at the lowest dose needed to maintain remission. Patients should be periodically reassessed to determine the need for maintenance treatment.
Re-initiation of Treatment in Patients Previoulsy Discontinued
Although there are no data to specifically address reinitiation of treatment, it is recommended that when restarting therapy of patients who have been off SEROQUEL XR for more than one week, the initial dosing schedule should be followed. When restarting patients who have been off SEROQUEL XR for less than one week, gradual dose escalation may not be required and the maintenance dose may be reinitiated.
Switching patients from SEROQUEL tablets to SEROQUEL XR tablets
Schizophrenic patients who are currently being treated with divided doses of SEROQUEL (immediate release formulation, eg. 2 to 3 times per day) may be switched to SEROQUEL XR at the equivalent total daily dose taken once daily. Individual dosage adjustments may be necessary.
Switching from Antipsychotics
There are no systematically collected data to specifically address switching patients with schizophrenia from other antipsychotics to SEROQUEL XR, or concerning concomitant administration with other antipsychotics. While immediate discontinuation of the previous antipsychotic treatment may be acceptable for some patients with schizophrenia, more gradual discontinuation may be most appropriate for others. In all cases, the period of overlapping antipsychotic administration should be minimized. When switching patients with schizophrenia from depot antipsychotics, if medically appropriate, initiate SEROQUEL XR therapy in place of the next scheduled injection. The need for continuing existing extrapyramidal syndrome medication should be reevaluated periodically.
DOSAGE FORMS AND STRENGTHS
200 mg extended — release tablets
300 mg extended — release tablets
400 mg sustained — release tablets
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