Warnings have been issued about drug suicides
Doctors want the availability of a drug restricted because they say hundreds of people are committing suicide using it.
The painkiller co-proxamol is prescribed to hundreds of thousands of people each year in the UK.
Unlike paracetamol, it cannot be bought over the counter at a chemist.
However, experts at the Centre for Suicide Research in Oxford say that, like paracetamol, it should be made more difficult for people to lay their hands on large quantities of the drug.
Their research highlighted co-proxamol as the second biggest method of drug-related suicide in the UK, accounting for almost one in five deaths.
The maximum number of paracetamol tablets that could be sold to a customer was reduced to 16 after research revealed how hundreds of people a year killed themselves with an overdose, and hundreds more survived, but suffered severe liver damage after suicide bids.
Research suggested that the measure had cut paracetamol-related suicides by a fifth.
Professor Keith Hawton, from the centre, looked at more than 4,000 drug-related suicides between 1997 and 1999 - and found that 18% involved just co-proxamol - compared with 9% which involved just paracetamol.
He concluded that people making an "impulsive" suicide bid were likely to favour the drug if substantial quantities could be found in the house.
"Reducing the availability of drugs used for suicide can result in reductions in deaths, and availability of co-proxamol should be restricted," he wrote in the British Medical Journal.
He said that studies had shown that co-proxamol, despite being a prescription-only drug, was no more effective than paracetamol for the relief of short term pain.
"Clinicians should consider whether there are other equally effective but less dangerous methods of pain relief," he wrote.
Roger Howard, the chief executive of the charity DrugScope, told BBC News Online that it favoured training doctors to be more aware of the potential use of certain drugs in suicide attempts.
He said: "The recourse to tighter regulation isn't always the answer in relation to the prescribing of drugs, such as co-proxamol.
"History has shown that influencing doctors prescribing habits through more effective training and education may be more suitable rather than ratcheting up regulatory restrictions."