An anonymous whistleblower has accused Swiss drugmaker Novartis of paying bribes in Turkey through a consulting firm to secure business advantages worth an estimated $85 million, according to an email sent to the company and leaked to the news agency Reuters.

Novartis has said it is investigating the allegations, which are thought to have included getting new drugs for multiple sclerosis, chronic lung disease or juvenile arthritis added to hospital formularies approved for prescription in government-run hospitals.

The drugmaker is also alleged to have avoided price cuts by securing government approval to change the names of two drugs, Ilaris and Gilenya, to Ibecta and Fingya. This meant they dropped out of international pricing comparisons, as such cross-referencing is based on commercial names.

The anonymous sender's email to Novartis CEO Joe Jimenez and Srikant Datar, chairman of its audit and compliance committee, said the company had paid Alp Aydin Consultancy the equivalent of $290,000 plus costs during 2013 and 2014, before the Turkish Social Security Institution (SSI) launched an investigation.

Reuters said Novartis confirmed Aydin had consulted for it in the past, but no longer did so.

The latest news comes on the heels of an agreement by Novartis to pay more than $25 million to settle a US Securities and Exchange Commission (SEC) case over bribery in China.

As reported by Reuters, the Swiss drugmaker also faces problems in South Korea, where its offices were visited by local authorities in February in relation to suspected bribery. The US government reportedly is also suing Novartis over marketing events said to have involved illegal kickbacks.