It took the government's Committee on Safety of Medicines seven months to act on comprehensive evidence that a schizophrenia drug widely given to control the behaviour of elderly people in care homes could cause them to have a stroke.
Last week the advisory body recommended doctors should not prescribe risperidone or olanzapine for such patients. But the manufacturer of risperidone - brand name Risperdal - gave the CSM full data about the risks last July.
Canadian and US drug regulators acted swiftly on early evidence from the manufacturers that Risperdal might cause death in the elderly.
In October 2002 Janssen-Ortho wrote to all health professionals, at the request of the Canadian authorities. In April 2003 the US regulators took similar action.
The vice-president of medical affairs of Janssen Pharmaceutica in New Jersey wrote: "[Strokes,] including fatalities, were reported in patients (mean age 85 years; range 73-97) in trials of risperidone in elderly patients with dementia-related psychosis.
"In placebo-controlled trials, there was a significantly higher incidence of cerebrovascular adverse events in patients treated with risperidone compared to patients treated with placebo. Risperdal has not been shown to be safe or effective in the treatment of patients with dementia-related psychosis."
But evidence came to light because the company carried out clinical trials in the hope of applying for a licence to market Risperdal for behavioural problems in the elderly.
Doctors were already using Risperdal on such patients.
Robert Donnelly, medical director of Janssen in the UK, said that when the first data came in there was "an imbalance" which they reported to the authorities worldwide.
That led to the letters in Canada and the US. By last summer they had the full trial data. This went to the UK's Medicines and Healthcare Products Regulatory Authority (MHRA). A Department of Health spokesman said the MHRA had acted at the same time as the Canadians and the Americans by adding a warning to doctors' product information that there might be an increased risk of stroke.
In April last year, he said, the company wrote to psycho-geriatricians in the UK.
But Robin Keen, who has investigated the worldwide advice since his mother, Urene, suffered a severe stroke while on Risperdal nine months ago, said the warnings would not necessarily have been noticed by doctors, and certainly did not go out to patients.
He added: "Practitioners may argue that many drugs have inherent risks, though when knowledge of that risk is clearly available, supported by the presence of clinical trial results, and even more so when that risk is of a life-threatening magnitude, then surely the patient, or that patient's relatives, have the right to that information in order to make an informed decision."
The health department said the MHRA had commissioned its own analysis of all the drug data in December after getting reports that those on the drugs were suffering strokes. It received the conclusions in January, and put out its advice to doctors last week.
