The Competition and Markets Authority (CMA) said the settlement follows an investigation into arrangements Aspen made with rival pharmaceutical firms in 2016, to keep them out of the market for the supply of Fludrocortisone 0.1 mg tablets.

The prescription-only treatment is paid for by the NHS in the UK, and the state-run health service had to pay higher prices for it because of Aspen's arrangements, the CMA said.

Fludrocortisone is mainly used to treat Addison's disease, in which the body's adrenal glands fail to produce sufficient hormones.

Britain's competition regulator said Aspen could also have to pay an additional 2.1 million pounds in fines as part of a wider package, if the investigation concludes that the company broke the law.

The regulator said it was also looking at two other companies that were involved in dealings with Aspen.

In a separate statement on Wednesday, Aspen said it would dispose its right to ambient Fludrocortisone in the UK to an independent third party, and would reintroduce cold storage versions of the treatment into the country.

(Reporting by Pushkala Aripaka in Bengaluru; Editing by Shounak Dasgupta)