Sepracor Announces Presentation of Lunesta™ Data at American Psychiatric Association Annual Meeting

Business Wire, May 22, 2006

MARLBOROUGH, Mass. -- Sepracor Inc. (Nasdaq: SEPR) today announced that data for LUNESTA(TM) brand eszopiclone for the treatment of insomnia will be presented at the annual meeting of the American Psychiatric Association in Toronto on May 23rd and 24th. The posters will be presented in the Toronto Convention Centre, North Level 300, Exhibit Hall B from 3:00 to 5:00 p.m. ET on both days.

The following posters will be at the meeting:

--The Effect of Eszopiclone 3 mg Compared with Placebo in Patients with Rheumatoid Arthritis and Co-Existing Insomnia

--Eszopiclone Co-Administered with Fluoxetine for Insomnia Co-Existing with Major Depressive Disorder (MDD): Effects Following Eszopiclone Discontinuation

--Eszopiclone Treatment During Menopausal Transition: Sleep Effects, Impact on Menopausal Symptoms and Mood

--Analysis of Individual Items of the Hamilton Depression Scale in a Study of Eszopiclone/Fluoxetine Co-Therapy

--Eszopiclone Co-Administered with Fluoxetine for Insomnia Co-Existing with Major Depressive Disorder (MDD): Analysis by Age

--The Relationship Between Eszopiclone's Effects on Sleep and Depression in Patients with New Onset Major Depressive Disorder (MDD) and Insomnia

Important Safety Information

LUNESTA is indicated for the treatment of insomnia. LUNESTA is not indicated for the treatment of depression, rheumatoid arthritis or menopause. LUNESTA works quickly and should only be taken immediately before bedtime. Be sure you have at least eight hours to devote to sleep before becoming active. You should not engage in any activity after taking LUNESTA that requires complete alertness, such as driving a car or operating machinery. You should use extreme care when engaging in these activities the morning after taking LUNESTA. Do not use alcohol while taking any sleep medicine. Most sleep medicines carry some risk of dependency. Do not use sleep medicines for extended periods without first talking to your doctor. Side effects may include unpleasant taste, headache, drowsiness and dizziness.

About Sepracor

Sepracor Inc. is a research-based pharmaceutical company dedicated to treating and preventing human disease by discovering, developing and commercializing innovative pharmaceutical products that are directed toward serving unmet medical needs. Sepracor's drug development program has yielded a portfolio of pharmaceutical products and candidates with a focus on respiratory and central nervous system disorders. Sepracor's corporate headquarters are located in Marlborough, Massachusetts.

Forward-Looking Statement

This news release contains forward-looking statements that involve risks and uncertainties, including statements with respect to the safety, efficacy and potential benefits of LUNESTA brand eszopiclone. Among the factors that could cause actual results to differ materially from those indicated by such forward-looking statements are: Sepracor's ability to fund, and the results of, further clinical trials; the timing and success of submission, acceptance, and approval of additional regulatory filings; the scope of Sepracor's patents and the patents of others; the commercial success of LUNESTA; the ability of the company to attract and retain qualified personnel; and certain other factors that are detailed in the company's quarterly report on Form 10-Q for the quarter ended March 31, 2006 filed with the Securities and Exchange Commission.

In addition, the statements in this press release represent Sepracor's expectations and beliefs as of the date of this press release. Sepracor anticipates that subsequent events and developments may cause these expectations and beliefs to change. However, while Sepracor may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Sepracor's expectations or beliefs as of any date subsequent to the date of this press release.

LUNESTA is a trademark of Sepracor Inc.

For a copy of this release or any recent release, visit Sepracor's web site at www.sepracor.com.