The Food and Drug Administration will ask an outside panel of advisors whether it should allow wider use of AstraZeneca Plc's drug Seroquel XR, which is currently approved to treat bipolar disorder and schizophrenia.

Seroquel is AstraZeneca's second-best-selling drug, with $4.5 billion in 2008 sales and Seroquel XR is an extended release version of the medicine with a longer patent life than the original formulation. AstraZeneca is seeking FDA approval to sell the extended version Seroquel XR for treating depression and anxiety, the company said the FDA had asked for additional information involving Seroquel for major depression.

In a notice posted on the FDA's Web site Tuesday, the FDA said it would convene its Psychopharmacologic Drugs Advisory Committee on April 8 to discuss the safety and effectiveness of Seroquel for treating generalized anxiety disorder and major depression.

The FDA said the issues for discussion at the April 8 advisory panel meeting include "concerns regarding exposing a greatly expanded population to a drug with known metabolic side effects and a possible risk of tardive dyskinesia," a neurological disorder that can be caused by drug exposure. Tardive dyskinesia causes involuntary, repetitive movement of the limbs and lip smacking, grimacing and other symptoms that can be permanent.

Seroquel and other antipsychotic drugs have been linked to weight gain, high blood sugar and lipid abnormalities such as increases in cholesterol and triglycerides. Seroquel's prescribing instructions carry warnings about possible side effects such as weight gain and diabetes and increases in cholesterol levels. Tardive dyskinesia also is mentioned as a possible complication.

Abigail Baron an AstraZeneca spokeswoman said, "AstraZeneca fully supports the work of the FDA in conducting a full review of the potential benefits and risks of Seroquel XR in the treatment of major depressive disorder and generalized anxiety disorder." She added that the product is safe and effective when used as recommended.