Sarah Jessica Parker may be best known for Carrie Bradshaw's colorful puns about women's footwear, but she's also acted as a spokesperson for Mylan, a pharmaceutical company that's recently faced widespread criticism surrounding a spike in the cost of EpiPens.

Parker has spoken on behalf of Mylan in various TV appearances and on social media since May, as part of the company's 'Anaphylaxis for Reel' campaign, Gizmodo explains.

Following reports accusing Mylan of increasing the prices of EpiPens by more than 400 percent over an eight year period, the actress announced that she severed her relationship with the company in a Thursday Instagram post.

“I was recently involved in an initiative to raise awareness for anaphylaxis,” Parker wrote. “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 who are at risk."

The "Sex and the City" star expressed her dismay at the price hike.

"I recently learned that the price of the EpiPen has been systematically raised by Mylan to a point that renders the medication cost-prohibitive for countless people," Parker continued. "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."

For families like Parker's, EpiPens are a crucial medical tool.

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About 3.6 million people in the US suffer from severe allergies to food or bee-stings, Quartz explains.

By counteracting anaphylactic shock with a shot of epinephrine, an Epi-Pen can literally be life-saving for someone experiencing a severe allergic reaction.

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As ATTN: has reported previously, Mylan's primary competitor, Sanofi, recalled an epinephrine auto-injector last year, leaving those in need of EpiPens with few other options. For low-income allergy sufferers, this could be especially devastating.

Since Mylan acquired the EpiPen patented technology in 2007, the insured price of a single EpiPen has risen from approximately $57 to $300, and can cost even more depending on patients' insurance plans, Quartz reports. An EpiPen expires after a year, requiring patients to purchase new ones annually.

Parker asked the company to take action.

"I hope they will seriously consider 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.