Sarah Jessica Parker has stepped down as the face of EpiPen.

Sarah Jessica Parker

Sarah Jessica Parker

The 51-year-old actress has decided to end her working relationship with the pharmaceutical giant Mylan, which makes the emergency anti-allergy medication to treat anaphylaxis, after it emerged the price of its life-saving injectors have spiked by 548 per cent since 2007.

Taking to her Instagram account on Thursday (25.08.16), she wrote: "I'm left disappointed, saddened and deeply concerned by Mylan's actions. I do not condone this decision and I have ended my relationship with Mylan as a direct result of it."

The blonde beauty agreed to be the ambassador of Mylan's Anaphylaxis 101 website in May as it's a subject close to her heart due to her 13-year-old son James, whom she has with her husband Matthew Broderick, suffering with a severe peanut allergy.

She explained: "It's a cause deeply important to me because of my son's life threatening peanut allergy.

"The Epinephrine Auto-Injector is a vital part of our family's healthcare, as it is for the many that are at risk."

It was claimed this week the price of the EpiPen twin pack had peaked to $608, which is an increase of more than $550 since 2007 when the medical device would set people back $57.

Sarah added: "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."

Following the star's decision to cut ties with the brand, Mylan has announced it will offer discounts for the EpiPen.