The International Journal of Neuropsychopharmacology

Research Article

Extended-release quetiapine fumarate (quetiapine XR): a once-daily monotherapy effective in generalized anxiety disorder. Data from a randomized, double-blind, placebo- and active-controlled study

Borwin Bandelowa1 c1, Guy Chouinarda2, Julio Bobesa3, Antti Ahokasa4, Ivan Eggensa5, Sherry Liua6 and Hans Erikssona6

a1 Department of Psychiatry and Psychotherapy, University of Goettingen, Germany

a2 Departments of Psychiatry and Medicine, Université de Montréal and McGill University, Montreal, QC, Canada

a3 Department of Psychiatry, University of Oviedo, Oviedo, Asturias, Spain

a4 Mehilainen Clinic, Helsinki, Finland

a5 AstraZeneca R&D Södertälje, Sweden

a6 AstraZeneca Pharmaceuticals, Wilmington, DE, USA


The efficacy and tolerability of extended-release quetiapine fumarate (quetiapine XR) once-daily monotherapy in generalized anxiety disorder (GAD) was assessed. This multicentre, double-blind, randomized, placebo- and active-controlled, phase III trial consisted of a 1- to 4-wk enrolment/wash-out period and a 10-wk (8-wk active treatment, 2-wk post-treatment drug-discontinuation) study period; 873 patients were randomized to 50 mg or 150 mg quetiapine XR, 20 mg paroxetine, or placebo. Primary endpoint was change from randomization at week 8 in Hamilton Rating Scale for Anxiety (HAMA) total score. At week 8, all active agents produced significant improvements in HAMA total and psychic subscale scores vs. placebo; HAMA somatic subscale scores were significantly reduced only by 150 mg quetiapine XR. Significant separation from placebo (−2.90) in HAMA total score was observed at day 4 for 50 mg quetiapine XR (−4.43, p<0.001) and 150 mg quetiapine XR (–3.86, p<0.05), but not for paroxetine (–2.69). Remission (HAMA total score xs2A7D7) rates at week 8 were significantly higher for 150 mg quetiapine XR (42.6%, p<0.01) and paroxetine (38.8%, p<0.05) vs. placebo (27.2%). The most common adverse events (AEs) were dry mouth, somnolence, fatigue, dizziness, and headache, for quetiapine XR, and nausea, headache, dizziness for paroxetine. A lower proportion of patients reported sexual dysfunction with quetiapine XR [0.9% (50 mg), 1.8% (150 mg)] than with placebo (2.3%) or paroxetine (7.4%). The incidence of AEs potentially related to extrapyramidal symptoms was: quetiapine XR: 50 mg, 6.8%, 150 mg, 5.0%; placebo, 1.8%; and paroxetine, 8.4%. Once-daily quetiapine XR is an effective and generally well-tolerated treatment for patients with GAD, with symptom improvement seen as early as day 4.

(Received December 15 2008)

(Reviewed March 02 2009)

(Revised June 25 2009)

(Accepted July 10 2009)

(Online publication August 20 2009)


c1 Address for correspondence: Professor Dr B. Bandelow, Department of Psychiatry and Psychotherapy, University of Goettingen, Von-Siebold-Str. 5, D-37075 Goettingen, Germany. Tel.: +49-551-396607 Fax: +49-551-398952 Email: