Exhibit 99.1

ENDO PHARMACEUTICALS ANNOUNCES

RECEIPT OF PARAGRAPH IV CERTIFICATION

CHADDS FORD, Pa., Jan. 19, 2010 — Endo Pharmaceuticals (NASDAQ: ENDP) announced today that its partners, Teikoku Seiyaku Co., Ltd. and Teikoku Pharma USA, Inc. have received a Paragraph IV Certification Notice from Watson Laboratories, Inc. advising of the filing of an Abbreviated New Drug Application (ANDA) for a generic version of LIDODERM^® (lidocaine topical patch 5%).

The company is currently reviewing the details of this notice from Watson. Endo intends to vigorously defend LIDODERM’s intellectual property rights and pursue all available legal and regulatory pathways in defense of LIDODERM.

The Paragraph IV certification notice refers to U.S. Patent No. 5,827,529, which covers the formulation of LIDODERM, a topical patch to relieve the pain of postherpetic neuralgia launched in 1999. This patent is listed in the U.S. Food and Drug Administration’s (FDA) Orange Book and expires in October 2015.

Citizen Petition

With respect to Endo’s regulatory approach, the company submitted a Citizen Petition in 2006 in reaction to a proposal by FDA’s Office of Generic Drugs that would diverge from applicable regulations and standards of practice regarding bioequivalence. The

company is requesting that the agency reconsider its departure from its longstanding general rule of requiring clinical endpoint bioequivalence studies for locally acting generic drug products, including those that reference LIDODERM. To ensure the safe and effective equivalence of any generic version to LIDODERM, which acts locally in the skin, Endo believes that FDA must return to its established standard of clinical endpoint bioequivalence studies.

About Endo

Endo Pharmaceuticals is a specialty pharmaceutical company engaged in the research, development, sale and marketing of branded and generic prescription pharmaceuticals used to treat and manage pain, prostate cancer and the early onset of puberty in children, or central precocious puberty (CPP). Its products include LIDODERM^®, a topical patch to relieve the pain of postherpetic neuralgia; Percocet^® and Percodan^® tablets for the relief of moderate-to-moderately severe pain; FROVA^® tablets for the acute treatment of migraine attacks with or without aura in adults; OPANA^® tablets for the relief of moderate-to-severe acute pain where the use of an opioid is appropriate; OPANA^® ER tablets for the relief of moderate-to-severe pain in patients requiring continuous, around-the-clock opioid treatment for an extended period of time; Voltaren^® Gel, which is owned and licensed by Novartis AG, a nonsteroidal anti-inflammatory drug indicated for the relief of the pain of osteoarthritis of joints amenable to topical treatment, such as those of the hands and the knees; VANTAS^® for the palliative treatment of advanced prostate cancer; SUPPRELIN^® LA for the treatment of early onset puberty in children; and VALSTAR™ for the treatment of BCG-refractory carcinoma in situ (CIS) of the urinary bladder in patients for whom immediate cystectomy would be associated with unacceptable medical risks. The company markets its branded pharmaceutical products to physicians in pain management, urology, endocrinology, oncology, neurology, surgery and primary care. More information, including this and past press releases of Endo Pharmaceuticals, is available at www.endo.com.

Safe Harbor Statement

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 regarding, among other things, the company’s financial position, results of operations, market position, product development and business strategy, as well as estimates of future net sales, future expenses, future net income and future earnings per share. Statements including words such as “believes,” “expects,” “anticipates,” “intends,” “estimates,” “plan,” “will,” “may,” “intend,” “guidance” or similar expressions are forward-looking statements. Because these statements reflect our current views, expectations and beliefs concerning future events, these forward-looking statements involve risks and uncertainties. Investors should note that many factors could affect our future financial results and could cause our actual results to differ materially from those expressed in forward-looking statements

contained in this press release. These factors include, but are not limited to: the possibility that the acquisition of Indevus is not complementary to Endo; the inherent uncertainty of the timing and success of, and expense associated with, research, development, regulatory approval and commercialization of our products and pipeline products; competition in our industry, including for branded and generic products, and in connection with our acquisition of rights to assets, including intellectual property; government regulation of the pharmaceutical industry; our dependence on a small number of products and on outside manufacturers for the manufacture of our products; our dependence on third parties to supply raw materials and to provide services for certain core aspects of our business; new regulatory action or lawsuits relating to our use of controlled substances in many of our core products; our exposure to product liability claims and product recalls and the possibility that we may not be able to adequately insure ourselves; our ability to protect our proprietary technology; our ability to successfully implement our in-licensing and acquisition strategy; the availability of third-party reimbursement for our products; the outcome of any pending or future litigation or claims by the government; our dependence on sales to a limited number of large pharmacy chains and wholesale drug distributors for a large portion of our total net sales; a determination by a regulatory agency that we are engaging in inappropriate sales or marketing activities, including promoting the “off-label” use of our products; the loss of branded product exclusivity periods and related intellectual property; and exposure to securities that are subject to market risk including auction-rate securities the market for which is currently illiquid; and other risks and uncertainties, including those detailed from time to time in our periodic reports filed with the Securities and Exchange Commission, including our current reports on Form 8-K, quarterly reports on Form 10-Q and annual reports on Form 10-K, particularly the discussion under the caption “Item 1A, RISK FACTORS” in our annual report on Form 10-K for the year ended December 31, 2008, which was filed with the Securities and Exchange Commission on March 2, 2009. The forward-looking statements in this press release are qualified by these risk factors. These are factors that, individually or in the aggregate, we think could cause our actual results to differ materially from expected and historical results. We assume no obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.

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