By Pat Anson, Editor

The makers of Cymbalta and Lyrica – two blockbuster drugs widely used to treat fibromyalgia and other chronic pain conditions – face legal battles this summer that could potentially cost the companies billions of dollars.

In London, a court case begins next week on Pfizer’s efforts to keep doctors in the U.K. from prescribing pregabalin – a cheaper generic version of Lyrica.

And in Los Angeles, a federal judge this week ordered Eli Lilly to face claims in lawsuits alleging that the company misled consumers about the side effects of withdrawal from Cymbalta.

Over 5,000 patients have filed suit against Lilly claiming that Cymbalta caused “brain zaps” – electric shocking sensations – as well as nausea, vomiting and insomnia when they stopped taking the drug.  The first two cases will be heard in August.

“The withdrawal symptoms from Cymbalta were hell,” wrote Crystal Lindell, a Pain News Network columnist in a recent article.

“Less than a week after my last pill, I was getting so dizzy that I seriously thought I had a new disease. Then, there was this thing called the brain zaps that I didn’t understand until they happened to me. In short, it literally felt like my brain was being, well, zapped by electricity. There was also nausea and vertigo and just an overall feeling of falling off a skyscraper.” 

Several readers shared their own experiences with Cymbalta.

“My neurologist put me on Cymbalta, I took 2 pills, I thought my head was going to explode,” wrote Judy Dunn.

“I suffered from 6 weeks of vertigo, nausea, dizziness, and MASSIVE headaches,” said Andy, who was prescribed Cymbalta to treat depression. “I will never take Cymbalta again. EVER.”

“While on the drug I did get a better mood and it helped a lot, but it raised my blood pressure and I was shaky and jittery. I also went through the brain ZAPS!!” wrote Candra Clark.

“We believe in our defenses to these claims and we will continue to defend Lilly vigorously,” Scott MacGregor, a Lilly spokesman told Bloomberg Business.

Cymbalta generated annual sales of $5 billion for Lilly until its patent expired in 2013 and cheaper generic versions of Doluxetine became available.

Lyrica Legal Battle

Like Cymbalta, Lyrica wasn’t originally developed to treat pain. It was used as a treatment for anxiety and epilepsy until drug maker Pfizer realized it could also be effective for fibromyalgia and neuropathic pain.

Pfizer’s patent on Lyrica for epilepsy and anxiety expired last year, but its secondary patent for pain is good until July of 2017 – and that is the essence of its legal fight in the U.K.

Rival drug makers started making pregabalin – the generic version of Lyrica – when its original patent expired. But it didn’t take long for doctors to also start prescribing pregabalin for pain.

According to Pharmalot, about 80% of all U.K. patients on pregabalin are using it to treat pain and Pfizer has launched an aggressive campaign to stop that. Last year the company wrote an unusual letter to physician groups in the U.K. warning them that prescribing pregabalin for pain was a violation of its patent.

“Pfizer believes the supply of generic pregabalin for use in the treatment of pain whilst the pain patent remains in force in the U.K. would infringe Pfizer’s patent rights,” the company said in the letter.

The Royal College of Physicians, which represents 29,000 U.K. doctors, responded with a statement of its own.

“Pregabalin is a useful drug for many patients and, given the current financial pressures the NHS (Britain’s National Health Service) is under, it is disappointing that a pharmaceutical company has made a move that will, potentially, prevent some patients from getting access to it,” a spokesman said.

The NHS has since issued guidance to doctors telling them to use the brand name Lyrica when prescribing pregabalin for pain “so far as reasonably possible.” Pfizer is seeking a stronger statement from the British High Court.

Ironically, Pfizer paid $2.3 billion dollars in 2009 to settle criminal and civil charges in the U.S. for the “off-label” marketing of Lyrica and other medications – the very sort of off-label use it is trying to stop in the U.K.

Lyrica remains one of Pfizer’s top selling drugs, generating $5.1 billion in revenue in 2014.