Hospital patients are being put at risk because medics are missing potentially lethal drug allergies, research out today shows.

Gaps in recording some elderly people's reactions were uncovered at Sunderland Royal Hospital.

A poll of 100 patients, admitted to the hospital, showed that records of allergies to drugs such as codeine, paracetamol and penicillin were either incomplete, overlooked or missed out altogether.

Researchers from Sunderland University found that in almost 40 per cent of patients with a known allergy, the reaction wasn't logged.

Pharmacists, not doctors, it noted recorded the tell-tale signs in about 80 per cent of cases.

Dr Rachel Etherington, who led the research said: "These allergies are not being picked up in a consistent manner. The target is to get all the health professionals – nurses, doctors and pharmacists – working together across the hospital, as a team."

The three-month study found that allergies could be noted on a patient's medical notes by a doctor, on a pharmacist's patient profile and on the hospital's own computer-based electronic prescribing system.

Dr Etherington, from the university's pharmacy school, said: "We found many inconsistencies. The computer system is probably the best way forward. It is getting people used to the fact that this is where information should be recorded on drug treatment, so everyone can access it.

"It is being picked up on, so it is not that it is going to be completely ignored. I don't know whether anything has been put in place yet."

Dr Etherington added: "Allergic reactions to drugs can have life-threatening consequences and are estimated to prolong the hospital stay for 15 per cent of patients."

A separate study by the University at Gateshead's Queen Elizabeth Hospital, found that fewer than half of patients with a known drug allergy were issued with red wrist bands, warning hospital staff.

Drug allergies were not mentioned in clinical notes or drug charts in three-quarters of the cases examined.