quetiapine, Seroquel, Seroquel XR (cont.)

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Medical and Pharmacy Editor:

Elderly patients with dementia-related psychosis treated with antipsychotics are at an increased risk of death. There is an increased risk of suicidal thinking and behavior in children, adolescents and young adults taking antidepressants for major depression and other psychiatric disorders.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 25, 50, 100, 200, 300 and 400 mg. Tablet (Extended Release): 50, 150, 200, 300 and 400 mg

STORAGE: Tablets should be stored at room temperature, 15 C to 30 C (59 F to 86 F).

DOSING: Immediate release quetiapine usually is taken two or three times daily. Extended release quetiapine is taken once daily. The dose usually is increased slowly over several days or weeks to achieve the desired effect. Quetiapine can be taken with or without food.

The initial dose for bipolar disorder is 50 mg twice daily (100 mg/day) of immediate release quetiapine. The dose can be increased by 100 mg/day to a daily dose of 400 mg/day. Most patients respond to 400-800 mg/day. Doses greater than 800 mg/d have not been studied. The starting dose is 300 mg once daily and the target dose is 400-800 mg once daily when using extended release tablets.

The initial dose for schizophrenia is 25 mg twice daily (50 mg/day) of immediate release tablets. The dose can be increased by 25-50 mg two or three times daily. The target dose is 300-400 mg/day in two or three doses. Patients respond to 150-750 mg/day, and doses greater than 800 mg/day have not been evaluated. The starting dose is 300 mg once daily and the target dose is 400-800 mg once daily when using extended release tablets.

The dose range for treating major depression is 150-300 mg/day of extended release tablets. The starting does is 50 mg in the evening for 2 days increasing to 150 mg in the evening.

DRUG INTERACTIONSPhenytoin (Dilantin) and thioridazine (Mellaril) markedly decrease the amount of quetiapine that is absorbed from the intestine and thereby reduces its effectiveness. Therefore, patients taking phenytoin or thioridazine may require higher doses of quetiapine.

Quetiapine can cause hypotension (low blood pressure) and therefore increase the blood pressure lowering effects of antihypertensive drugs and result in lower blood pressure.

Quetiapine can add to the sedating effects of other drugs that sedate. Such drugs include narcotic pain relievers (for example, oxycodone and acetaminophen [Percocet, Roxicet, Tylox, Endocet]), barbiturates, sedatives such as alprazolam [Xanax] and clonazepam [Klonopin], ethanol, and blood pressure drugs that can cause orthostatic hypotension, such as prazosin (Minipress) and terazosin (Hytrin).

Medically Reviewed by a Doctor on 12/12/2014


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