Household goods giant Reckitt Benckiser has been accused of abusing its dominant position in the supply of heartburn medicines to the NHS.

The Office of Fair Trading alleges that Reckitt Benckiser sought to restrict competition to its Gaviscon treatment by offering family doctors only a more expensive version of the product when they searched prescribing software.

The OFT said Reckitt deliberately delisted a sister product just before cheaper generic rivals joined the list

Doctors use software to search for branded products and then provide patients with an “open” prescription that lists its generic name.

This allows pharmacies to choose whether to dispense the brand or a cheaper rival, at considerable cost savings to the NHS.

In a statement of objections, the OFT said Reckitt deliberately delisted a sister product just before cheaper generic rivals joined the list.

The timing of this meant that an NHS doctor searching for Gaviscon would instead bring up its Gaviscon Advance Liquid - a patent protected version that did not have an “open” prescription that would have allowed generic rivals to be shown to GPs, according to the OFT.

Simon Williams, senior director for goods at the OFT, said: “This case raises significant and complex competition issues relating to the supply of prescription drugs to the NHS.”

The OFT said it would wait for a response from Reckitt before giving a final verdict on whether it believes competition law has been broken.