The government's medicines advisors are investigating the risks associated with the common painkiller co-proxamol.
The CSM is reviewing co-proxamol's safety
The Medicines and Healthcare products Regulatory Agency is concerned about the number of accidental and intentional overdoses with this drug.
It says a high number of overdoses is still being seen, despite clear dosage instructions being spelt out on patient information leaflets.
The Committee on Safety of Medicines is also reviewing the drug's safety.
Co-proxamol is a prescription-only medicine used to treat mild and moderate pain and has been available since the 1960s.
It contains a fixed dose combination of paracetamol and a weak opioid painkiller called dextropropoxyphene.
MHRA advice on co-proxamol
Only take it if it has been prescribed for you
Read the patient information leaflet and follow its instructions
Do not take more than the recommended dose
Never take it with alcohol, sedatives, tranquillisers or other medicines containing paracetamol
Store you medicine out of sight and reach of children and adolescents
Destroy any unused tablets or return them to your pharmacist
About 300-400 people in England and Wales die each year after taking more than the recommended amount.
About a fifth of these are thought to be accidental overdoses and the rest deliberate.
Co-proxamol is no better than full strength paracetamol at relieving pain and is known to be very toxic in overdose.
For this reason the Committee on Safety of Medicines, an independent expert body that advises the government on medicines, is currently looking at the risks and benefits of co-proxamol.
The request by the MHRA for doctors to send in their experiences is aimed at helping the committee conduct its review.
Chairman of the MHRA Sir Alasdair Breckenridge said: "The MHRA and CSM would like to consider any further evidence on the risks and benefits of co-proxamol to decide whether any further action is needed.
"Whilst this review is ongoing, prescribers are being reminded again on ways to minimise the risk of fatal overdose," he said.
David Pruce, Director of Practice and Quality Improvement at the Royal Pharmaceutical Society of Great Britain, said they supported the safety review.
"It is right that the CSM establishes whether the benefits of prescribing co-proxamol outweigh the risks.
"The risks of overdosing with co-proxamol are well known but measures taken so far have failed to reduce the number of fatalities. We await the results of the CSM's review with interest."