A combination of paracetamol 500mg and ibuprofen 200mg  is likely to be effective in 70 per cent of patients with moderate or severe acute post-operative pain, a Cochrane Review has shown.

Etoricoxib given at a strength of 120mg was equally effective, the review showed, but other pain killers such as paracetamol 600mg or aspirin 1,000mg taken alone helped only 35 per cent of patients.

The report, published in the Cochrane library, looked at 35 Cochrane reviews of randomised trails relating to about 45,000 patients involved in around 350 individual studies.

The review showed that no drug produced high levels of pain relief in all patients. Author Andrew Moore, of the Oxford Pain Research Unit at Oxford University, said that all options should be explored for patients.

"If the first painkiller a person tries doesn't seem to be working, then doctor should look to find an alternative reliable drug and see if it is more effective in that individual patient. There are plenty of options that have a solid evidence base," said Dr Moore.

The period over which pain was relieved in the patients in the trials around varied, with relief lasting from two hours to 20 hours.

The review looked at how well different drug and dose combinations worked against acute pain.