Seroquel XR (the "XR" stands for "extended-release") is approved to treat schizophrenia and bipolar disorder. Its maker, the drug company AstraZeneca, is seeking FDA approval for Seroquel XR as a generalized anxiety disorder treatment.
In the new study, 854 generalized anxiety disorder patients were given either Seroquel XR, Lexapro (a prescription drug approved to treat generalized anxiety disorder and depression), or a placebo without knowing which pill they were receiving.
For eight weeks, the patients took their assigned pills daily. During that time, Seroquel XR and Lexapro beat the placebo at reducing anxiety, according to surveys completed by the patients.
Those improvements started on the fourth day of taking Seroquel XR. Lexapro was "also effective, but improvement was not seen by Day 4," write the researchers. They included Charles Merideth, MD, of the Affiliated Research Institute Inc., a San Diego company that conducts medication studies for drug companies.
The most common side effects reported in the study were dry mouth, sleepiness, sedation, nausea, dizziness, and headache (with all pills). Constipation and insomnia were also on the list for Seroquel XR; fatigue and diarrhea were common side effects in the Lexapro group.
The study was presented in Barcelona, Spain, earlier this week at the European College of Neuropsychopharmacology's 21st congress and funded by the drug company AstraZeneca. Two of Merideth's colleagues are AstraZeneca employees.
Seroquel, like all "atypical" antipsychotic drugs, bears a "black box" warning, the FDA's sternest warning, about increased risk of death in elderly patients with dementia. In June, the FDA ordered the same "black box" warning for all conventional antipsychotic drugs. And like all prescription drugs used to treat depression, Seroquel (and Lexapro) bear "black box" warnings about suicide risk in children, teens, and young adults.