An end to prescriptions for a common painkiller has led to a drop in suicides involving the drug - without a rise in deaths from other painkillers.

Co-proxamol was once the most common prescription drug used in suicides and between 1997 and 1999 was behind 766 deaths in England and Wales, according to the study published on bmj.com.

Scientists said withdrawing co-proxamol from the UK market was followed by a "major" reduction in suicides and accidental poisonings involving the drug, which has a "relatively narrow" margin between the concentration at which it is therapeutic and that at which it can kill.

Co-proxamol was taken by Government scientist David Kelly, who killed himself in 2003 in the row over the Iraq war weapons of mass destruction dossier.

It was concerns about the large numbers of fatal poisonings which prompted the Committee on Safety in Medicines to announce co-proxamol would be phased out in the UK by the end of 2007, but it was not clear whether the plan to cut deaths had worked.

Oxford University scientists, led by Professor Keith Hawton, studied national records to establish how successful the initiative has been in reducing the number of deaths.

They found a steep fall (59%) in the prescribing of co-proxamol after the 2005 announcement of its withdrawal and - unsurprisingly - significant increases in the prescribing of other painkillers such as co-codamol, paracetamol and codeine.

Crucially, the changes in prescribing practices were accompanied by a 62% reduction in suicides involving co-proxamol, or 295 fewer deaths - a figure which rose to 349 when accidental poisonings were included - compared to expected levels.

Yet there was no increase in deaths involving other painkillers and prescription drugs, allaying fears that people would substitute co-proxamol for other drugs in suicide attempts, according to the report's authors.

The team concluded that the UK initiative has been an effective measure, highlighting how regulatory authorities "can have an important public health function", as was previously found in relation to restricting the pack sizes of over-the-counter painkillers.