Major drug companies are to be sued over claims that they didn't warn patients quickly enough of the possible bizarre side effects of a drug for Parkinson's Disease.
By Meirion Jones
The law firm Leigh Day alleges that the drug - Mirapex - can lead to some patients becoming compulsive gamblers.
Two companies, Boehringer Ingelheim and Pfizer were involved in the manufacture and distribution of the drug.
BBC Newsnight talked to Mirapex patients and doctors. One man said he lost £1m, while a female patient said she attempted suicide after facing financial ruin.
Doctors say the compulsion vanished once the medication regime was changed.
Pfizer said they no longer promote the product and suggested we contact Boehringer Ingelheim (BI). BI said it was company policy not to comment on litigation but they said it was, "the first pharmaceutical company... to add information about reports of pathological gambling associated with patients", using Mirapex and other dopamine agonists.
BI added that, "pathological gambling may also be both part of the disease itself and potentially related to all dopamine agonists," as well as other treatments for Parkinson's such as levidopa.
A partner at Leigh Day, Bozena Michelowska-Howells, said the writs would be issued this month.
"We are about to issue proceedings on behalf of complainants who are bringing a claim against the manufacturers of Mirapex for damages suffered as a result of the compulsive behaviour brought on by the drug", she said.
"Prior to taking the drug none of them had any record of compulsive behaviour particularly pathological gambling. They started to develop a compulsive urge to gamble which was uncontrollable. This urge effectively led them to financial ruin and in many cases suicide attempts."
The Parkinson's Disease Society say that as many as one in seven of patients on drugs such as Mirapex can be at risk of developing compulsive behaviour disorders but research is continuing to discover how widespread the problem is.
Mirapex and other similar drugs which are called dopamine agonists attempt to compensate for the lack of dopamine in Parkinson's patients which makes them shake uncontrollably.
They have improved the life of many patients but the legal case is likely to focus on whether the company should have given earlier warning of the potential side effects.
Newsnight has learned that from the mid 1990s clinical trials showed Mirapex patients were reporting compulsive disorders which investigators thought might be linked to the drug.
In 1996 a Mirapex patient was hospitalised for depression after developing a gambling addiction. By 2000 scientific papers began linking gambling problems to Parkinson's drugs and in 2003 the scientific journal Neurology published a study by researcher Erika Driver Dunckley which concentrated on Mirapex and suggested gambling addiction "appeared to begin with an increase in (dopamine agonist) therapy."
The paper continued, "it may be appropriate to inform subjects of a potential risk of this behaviour".
Erika Driver Dunckley is Assistant Professor at the Mayo Clinic in Phoenix Arizona which specialises in Parkinson's treatment. She told Newsnight she was sure the compulsive behaviour was caused by Mirapex. "When they stopped taking the drug," she told us, "their gambling habits ceased."
But despite the call for a warning in 2003 it was not until March 2005 that drug company Boehringer Ingelheim put a warning on package leaflets.
It read: "There have been reports of patients treated with Mirapexin, especially at high doses, showing pathological gambling".
It wasn't till 2006 that the warning was strengthened and placed higher up the leaflet: "Patients and caregivers should be aware of the fact that behavioural changes can occur (eg pathological gambling, increased libido, binge eating.)"
Urge to gamble
Newsnight talked to Tricia Wragg who lives on the edge of the Peak District and was diagnosed with Parkinson's in her early 40s. When she went on Mirapex she turned overnight into a reckless gambler. She says it was, "totally, totally out of character. I knew exactly what money was worth. I had to work hard for it".
She was given the drug Mirapex to treat the symptoms. But something began to happen.
From the odd game of bingo, she developed an uncontrollable urge to gamble.
"I was using my debit card until there was no money in the bank to use. I used my daughter's credit card, my husband's credit card. It made me very devious, I would do anything to get money off anyone. I would tell lies."
Tricia ran up debts of more than £35,000. When she stopped taking Mirapex, her urge to gamble vanished.