Reckitt Benckiser faces an investigation into sales of its Gaviscon heartburn medicines to the NHS after the OFT accused it of abusing its dominant market position.The OFT alleges that Reckitt Benckiser sought to restrict competition to its Gaviscon brand by withdrawing and de-listing its NHS packs of Gaviscon Original Liquid from the NHS prescription channel just before its patent ran out. The OFT alleges that this withdrawal from the NHS prescription channel was deliberately timed to so that when GPs search for 'Gaviscon' prescription packs they will identify Gaviscon Advance Liquid, which is patent protected, rather Gaviscon Original Liquid, which is now unpatented and listed by its generic name.“No assumption should be made at this stage that there has been an infringement of competition law,” the OFT said, adding it will wait for Reckitt’s response before making a decision.'This case raises significant and complex competition issues relating to the supply of prescription drugs to the NHS. Reckitt Benckiser will now have a full opportunity to respond to our proposed findings before we decide whether competition law has in fact been infringed,' said Simon Williams, Senior Director for Goods at the OFT.