AVANIR Presents Data at American Neurological Association Annual Meeting

PK/PD Modeling Predicts Improved Safety and Continued Efficacy of New Zenvia Formulation

Pseudobulbar Affect Causes Significant Burden to Caregivers

ALISO VIEJO, Calif., September 23, 2008 - AVANIR Pharmaceuticals (NASDAQ:AVNR) today announced the presentation of two posters at the American Neurological Association's 133rd Annual Meeting in Salt Lake City. The posters covered the results of the pharmacokinetic/pharmacodynamic (PK/PD) modeling that was used to predict the safety and efficacy of the new lower dose formulation of Zenvia (dextromethorphan/quinidine [DM/Q]) now being tested in the ongoing STAR Phase III trial, as well as the impact of pseudobulbar affect (PBA) on caregivers.

"We are very pleased that these important data were presented at the prestigious American Neurological Association meeting," said Randall Kaye, MD, Chief Medical Officer of AVANIR Pharmaceuticals. "The PK/PD modeling results being presented were instrumental in allowing the Company to move forward with a new lower dose formulation of Zenvia to be studied in the treatment of PBA. In addition, the survey data have provided us with important insight into the increased burden faced by caregivers who care for people suffering from PBA secondary to neurologic disease or injury."

Highlights of Posters

Poster T172:Pharmacokinetic/Pharmacodynamic Modeling of Dextromethorphan/Quinidine for a Study in Pseudobulbar Affect

Benjamin Brooks, MD, Director, Carolinas Neuromuscular / ALS Center, Carolinas Healthcare System, was the lead author on Poster T172. The present model is the basis of an ongoing clinical trial of DM/Q for PBA. PK/PD modeling analyses were undertaken to predict whether a change to a lower dose formulation of Zenvia would improve the treatment's cardiovascular safety profile while maintaining efficacy. The authors concluded that PK/PD modeling can assist with the dose-selection process during drug development in order to help maximize the benefit/risk ratio of a planned therapeutic intervention.

Poster T288:Impact of Pseudobulbar Affect on Caregivers

Daniel Wynn, MD, Director, Clinical Research, Co-Director, Consultants in Neurology Multiple Sclerosis Center in Northbrook, IL, was the lead author on Poster T288. The authors concluded that caring for PBA patients imposes burdens on caregivers beyond those of caring for demographically matched patients with the same underlying neurologic disorders who do not have PBA. The burdens include increased work impairment, reduced work productivity, and substantial negative impact on maintaining employment and on aspects of the caregiver's life (vacation, friendships, and relationships). This finding emphasizes the importance of the development of specific therapies targeted at this frequent complication of increasingly common debilitating neurologic disorders.

For more details, a PDF version of each poster can be found at the Company's website.

About PBA

Pseudobulbar affect, also known as involuntary emotional expression disorder (IEED) or emotional lability, is a neurologic disorder that occurs secondary to neurologic disease or brain injury causing sudden and unpredictable episodes of crying, laughing, or other emotional displays. PBA is estimated to impact more than 1.8 million people in the United States with underlying neurologic conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Parkinson's disease, dementias including Alzheimer's disease, stroke, and traumatic brain injury. PBA episodes may occur when disease or injury damages the area of the brain that controls normal expression of emotion. This damage can disrupt brain signaling, causing a "short circuit" and triggering involuntary PBA episodes. PBA has been shown to impair the lives of patients in both social and occupational settings. There are currently no FDA-approved treatments for PBA. Further information about PBA can be found at www.PBAinfo.org.

About Zenvia

Zenvia is a combination of two well-characterized compounds: the therapeutically active ingredient dextromethorphan and the enzyme inhibitor quinidine, which serves to increase the bioavailability of dextromethorphan. This first-in-class drug candidate is believed to help regulate excitatory neurotransmission in two ways: through pre-synaptic inhibition of glutamate release via sigma-1 receptor agonist activity and through postsynaptic glutamate response modulation via uncompetitive, low-affinity NMDA antagonist activity. Zenvia is currently in development for the treatment of PBA and diabetic peripheral neuropathic (DPN) pain. In October 2006, the Company received an approvable letter for Zenvia in the treatment of PBA. The Company has initiated a confirmatory Phase III study under a Special Protocol Assessment (SPA) agreement with the FDA utilizing a new lower quinidine dose formulation of Zenvia intended to address safety concerns raised in the Agency's approvable letter for Zenvia in the treatment of PBA. For more information about this trial visit http://www.pbatrial.com and for more information about the Agency's SPA process see http://www.fda.gov/cder/guidance/3764fnl.htm. In April 2007, AVANIR announced successfully meeting all primary endpoints in a Phase III study of Zenvia in DPN pain. In May 2008, the Company released top-line results of a formal PK study that identified alternative lower-dose quinidine formulations of Zenvia for DPN pain intended to deliver similar efficacy and improved safety/tolerability versus the formulations previously tested for this indication.

About AVANIR

AVANIR Pharmaceuticals is focused on acquiring, developing, and commercializing novel therapeutic products for the treatment of chronic diseases. AVANIR's products and product candidates address therapeutic markets that include the central nervous system, inflammation, and infectious diseases. AVANIR's lead product candidate, Zenvia, is being developed for the treatment of PBA and DPN pain. AVANIR has licensed its MIF inhibitor program to Novartis International Pharmaceuticals Ltd. and has sold its anthrax monoclonal antibody program to Emergent BioSolutions. The Company's first commercialized product, Abreva®, is marketed in North America by GlaxoSmithKline Consumer Healthcare and is the leading over-the-counter product for the treatment of cold sores. Further information about AVANIR can be found at www.avanir.com and further information about pseudobulbar affect can be found at www.PBAinfo.org.

Forward Looking Statements

Statements in this press release that are not historical facts, including statements that are preceded by, followed by, or that include such words as "estimate," "intend," "anticipate," "believe," "plan," "goal," "expect," or similar statements, are forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from the future results expressed or implied by such statements. There can be no assurance that any new doses of Zenvia for PBA or DPN pain will be safe and effective, that any additional Phase III trial for Zenvia will be successful or that the U.S. Food and Drug Administration (FDA) will approve Zenvia for any indication, that the Company will meet clinical development timelines, that the Company will be able to achieve targeted levels of expenditures or that the Company will be able to secure additional worldwide intellectual property protection for its Zenvia patent portfolio. There can be no assurances that Zenvia clinical development programs for indications other than PBA will move forward without additional capital or partnerships. There can also be no assurance that the proceeds from the Company's recently completed offering of common stock and warrants will be sufficient to fund our clinical trials to completion as expected or to fund operations through the expected timing of an approval decision from the FDA. Risks and uncertainties affecting the Company's financial condition and operations also include the risks set forth in AVANIR's most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q, and from time-to-time in other publicly available information regarding the Company. Copies of this information are available from AVANIR upon request. AVANIR disclaims any intent to update these forward-looking statements.

To be included on AVANIR's e-mail alert list; click on the link below or visit AVANIR's website:

http://www.b2i.us/irpass.asp?BzID=958&to=ea&s=0

AVANIR Investor Contacts
Eric Benevich or Brenna Mullen
949-389-6700
ir@avanir.com

Sep 23, 2008