Obesity has been considered a disease or illness requiring medication by several drug manufacturers. The history of those obesity drugs appears in the chart below, which also lists each drug's status along with the reasons for being discontinued or rejected, where applicable.
Years on the market
Status of drug in United States (as of July 20, 2011) along with reasons for being discontinued or rejected, if applicable
Available over-the-counter. Lower-dose, over-the-counter version of Xenical (see above). Can cause serious liver problems, uncontrolled bowel movements, and gas.
Not applicable (rejected by the FDA in June 2007) 
Rejected. Suspected of causing suicidal thoughts.
Not applicable (rejected by the FDA on Oct. 22, 2010) 
Rejected. Possible cancer risk suspected after tumors were found in lab animals.
Not applicable (rejected by the FDA on Oct. 28, 2010) 
Qnexa (combination of topiramate and phentermine)
Rejected. FDA requested more data on heart risks and other issues.
Not applicable (rejected by the FDA on Jan. 31, 2011) 
Contrave (bupropion and naltrexone)
Rejected. FDA requested a clinical trial to evaluate heart risks.
The chart above was based primarily on the Feb. 1, 2011, Reuters article titled "Factbox: A Troubled History of Obesity Drugs," with reporting by Julie Steenhuysen, Susan Heavey, Jon Lentz and Lisa Richwine, and editing by Tim Dobbyn and Matthew Lewis, and supplemented with the 19 sources below.
George A. Bray, "Some Historical Aspects of Drug Treatment for Obesity," Pharmacotherapy of Obesity, Ed. John P. H. Wilding, 2008
David S. Weigle, "Pharmacological Therapy of Obesity: Past, Present, and Future," Journal of Clinical Endocrinology & Metabolism, June 2003
"FDA Issues Complete Response to New Drug Application for Contrave(R) for the Management of Obesity," www.orexigen.com, Feb. 1, 2011
"Calories Count: Report of the Working Group on Obesity," www.fda.gov, Mar. 12, 2004
Alok. K. Gupta and Frank L. Greenway, "Safety of Obesity Drugs," Obesity: Epidemiology, Pathophysiology and Prevention, Eds. Debasis Bagchi and Harry G. Preuss, 2007
George A. Bray, "History of Obesity," Obesity: Science to Practice, Eds. Gareth Williams and Gema Frühbeck, 2009
Robert Pool, Fat: Fighting the Obesity Epidemic, 2001
"FDA Approved Obesity Drugs," www.fda.gov (accessed July 21, 2011)
National Center for Biotechnology Information (NCIB), "Phentermine," PubMed Health database, www.ncbi.nlm.nih.gov, Jan. 1, 2011
National Center for Biotechnology Information (NCIB), "Diethylpropion," PubMed Health database, www.ncbi.nlm.nih.gov, Sep. 1, 2008
"FDA Announces Withdrawal Fenfluramine and Dexfenfluramine (Fen-Phen)," www.fda.gov, July 7, 2005
"Early Communication about an Ongoing Safety Review Orlistat (Marketed as Alli and Xenical)," www.fda.gov, Aug. 24, 2009
Tse-Ling Fong, MD, et al., "Hepatotoxicity Due to Hydroxycut: A Case Series," American Journal of Gastroenterology, July 2010
Amy Norton, "Hydroxycut Linked to Other Cases of Liver Damage," www.reuters.com, Feb. 12, 2010
Home page, www.hydroxycut.com (accessed July 21, 2011)
Andrew Pollack, "Abbott Labs Withdraws Meridia from the Market," www.NYTimes.com, Oct. 8, 2010
"Akyuz, Sinan 11/16/09 – Warning Letter," www.fda.gov, Nov. 16, 2009
Andrew Pollack, "No F.D.A. Approval for New Diet Pill," www.NYTimes.com, Oct. 23, 2010
Andrew Pollack, "F.D.A. Rejects Qnexa, a Third Weight-Loss Drug," www.NYTimes.com, Oct. 28, 2010