Salix Pharmaceuticals Acquires Worldwide Rights to Olon's Intellectual Property Relating to Amorphous Rifaximin

Salix Pharmaceuticals, Ltd. (NASDAQ:SLXP) today announced that as of May 30, 2013, it had purchased from Olon S.p.A. (formerly Solmag) a pending patent application claiming amorphous rifaximin and an issued patent that Olon recently acquired from Apotex Pharmachem, Inc. claiming amorphous rifaximin, together with related intellectual property rights. Additionally, Olon granted Salix the exclusive worldwide right under Olon’s intellectual property rights to exploit amorphous rifaximin.

About XIFAXAN® (rifaximin) 550 mg tablets

Indication for XIFAXAN® 550 mg

XIFAXAN 550 mg is a rifamycin antibacterial indicated for reduction in risk of overt hepatic encephalopathy (HE) recurrence in patients ≥ 18 years of age.

Important Safety Information for XIFAXAN® 550 mg

XIFAXAN (rifaximin) 550 mg tablets are contraindicated in patients with a hypersensitivity to rifaximin, any of the rifamycin antimicrobial agents, or any of the components in XIFAXAN. Hypersensitivity reactions have included exfoliative dermatitis, angioneurotic edema, and anaphylaxis.

Clostridium difficile-associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including XIFAXAN, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon which may lead to overgrowth of C. difficile. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.

There is increased systemic exposure in patients with more severe hepatic dysfunction. The clinical trials were limited to patients with MELD scores < 25. Therefore, caution should be exercised when administering XIFAXAN to patients with severe hepatic impairment (Child-Pugh C).

Based on animal data, XIFAXAN may cause fetal harm. Discontinue in nursing mothers after taking into account the importance of the drug to the mother.

The most common adverse reactions occurring in ≥ 10% of patients and at a higher incidence than placebo in the clinical study were edema peripheral (15%), nausea (14%), dizziness (13%), fatigue (12%), and ascites (11%).

Xifaxan 550 mg is not available for sale outside the U.S.

Xifaxan 550 mg is licensed by Alfa Wassermann S.p.A. to Salix Pharmaceuticals, Inc.

About Salix

Salix Pharmaceuticals, Ltd., headquartered in Raleigh, North Carolina, develops and markets prescription pharmaceutical products for the prevention and treatment of gastrointestinal diseases. Salix’s strategy is to in-license late-stage or marketed proprietary therapeutic products, complete any required development and regulatory submission of these products, and market them through the Company’s gastroenterology specialty sales and marketing team.

Salix markets XIFAXAN® (rifaximin) tablets 200 mg and 550 mg, MOVIPREP® (PEG 3350, Sodium Sulfate, Sodium Chloride, Potassium Chloride, Sodium Ascorbate and Ascorbic Acid for Oral Solution), OSMOPREP® (sodium phosphate monobasic monohydrate, USP and sodium phosphate dibasic anhydrous, USP) Tablets, APRISO® (mesalamine) extended-release capsules 0.375 g, GIAZO™ (balsalazide disodium) tablets, COLAZAL® (balsalazide disodium) Capsules, METOZOLV® ODT (metoclopramide HCl), RELISTOR® (methylnaltrexone bromide) Subcutaneous Injection, FULYZAQ™ (crofelemer) delayed-release tablets, SOLESTA®, DEFLUX®, PEPCID® (famotidine) for Oral Suspension, DIURIL® (Chlorothiazide) Oral Suspension, AZASAN® (Azathioprine) Tablets, USP, 75/100 mg, ANUSOL-HC® 2.5% (Hydrocortisone Cream, USP), ANUSOL-HC® 25 mg Suppository (Hydrocortisone Acetate), PROCTOCORT® Cream (Hydrocortisone Cream, USP) 1% and PROCTOCORT® Suppository (Hydrocortisone Acetate Rectal Suppositories) 30 mg. Budesonide foam, RELISTOR® , LUMACAN™ and rifaximin for additional indications are under development.

For full prescribing information and important safety information on Salix products, including BOXED WARNINGS for OSMOPREP, AZASAN and METOZOLV, please visit www.salix.com where the Company promptly posts press releases, SEC filings and other important information or contact the Company at 919 862-1000.

Salix trades on the NASDAQ Global Select Market under the ticker symbol “SLXP”.

For more information, please visit our Website at www.salix.com or contact the Company at 919-862-1000. Follow us on Twitter (@SalixPharma) and Facebook (www.facebook.com/SalixPharma). Information on our Twitter feed, Facebook page and web site is not incorporated in our SEC filings.

Please Note:The materials provided herein that are not historical facts are or might constitute forward-looking statements under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Although we believe the expectations reflected in such forward-looking statements are based on reasonable assumptions, our expectations might not be attained. Forward-looking statements involve known and unknown risks that could cause actual results to differ materially from expected results. Factors that could cause actual results to differ materially from our expectations expressed in the report include, among others: the possible impairment of, or inability to obtain intellectual property rights and the costs of obtaining such rights from third parties in an increasingly global market; our dependence on our first seven pharmaceutical products, particularly Xifaxan, and the uncertainty of market acceptance of our products; the high cost and uncertainty of the research, clinical trials and other development activities involving pharmaceutical products; the unpredictability of the duration and results of regulatory review of New Drug Applications and Investigational New Drug Applications; intense competition, including from generics in an increasingly global market; general economic conditions; our need to maintain profitability; the uncertainty of obtaining, and our dependence on, third parties to manufacture and sell our products; results of ongoing and any future litigation and investigations and other risk factors detailed from time to time in our other SEC filings.