Glaxo Wellcome Plc and Smithkline Beecham Plc have been forced to postpone the completion date for their planned merger from September 25 to “the end of the year”. The move follows concerns raised by the American Federal Trade Commission about the sale of smoking cessation products in the United States. Glaxo Wellcome markets Zyban (amfebutamone or bupropion) in the US while Smithkline Beecham sells the over-the-counter nicotine replacement therapy products Nicorette and Nicoderm.