Sarah Jessica Parker has cut ties with the makers of the emergency allergy treatment EpiPen after voicing concerns about its price hike.

The Sex and The City star, whose 13-year-old son James has severe peanut and hazelnut allergies, had previously taken part in a short campaign with pharmaceutical giant Mylan NV, the maker of the EpiPen.

The company is facing criticism after the list price of an EpiPen twin-pack climbed to 608 dollars (£460), up from around 100 dollars in 2007 (£75).

Actress Sarah Jessica Parker with husband Matthew Broderick and their son James
Sarah Jessica with husband Matthew Broderick and their son James (Kathy Willens/AP)

In a post on Instagram, Sarah Jessica said she was “disappointed, saddened and deeply concerned by Mylan’s actions” and she was ending her relationship with the company.

“I hope they will seriously reconsider the outpouring of voices of those millions of people who are dependent on the device, and take swift action to lower the cost to be more affordable for whom it is a life-saving necessity,” she wrote.

Mylan NV has promised to reduce the costs that some patients pay for the treatment by “doubling eligibility” for its EpiPen patient assistance programme, which subsidises the cost of the drugs for low-income patients.