(6 March 2005)A widely used treatment for a type of life threatening chest infection is essentially ineffective, say experts.
Some people with pneumonia develop an infection of the lining that coats the outside of the lung, called the pleura.

Draining off the infected pus that collects between the lung and the chest wall helps, and some believe adding a drug into the space speeds this up.

But a Medical Research Council study in the New England Journal of Medicine calls into question this rationale.

Previous studies suggesting some benefit of administering so-called 'fibrinolytic' drugs, such as streptokinase, into the chest cavity have involved only small numbers of patients.

It was thought that these drugs might help make the fluid more runny and break down any pockets of pus so it is easier to drain.

Streptokinase is also used to break down blood clots in patients who have had a stroke.

Draining pus

The MRC study looked at over 450 patients across 52 UK hospitals to provide more definitive evidence.

Half of the patients were given an streptokinase therapy into the chest cavity before the fluid was drained using a tube in the usual way. The other half were given only a saline solution before the fluid was drained.

All of the patients received appropriate antibiotic therapy.

The streptokinase treatment was found to be no better than the 'dummy' saline treatment in terms of death risk or need for surgery to drain 'difficult to remove' fluid.

Lead researcher Dr Robert Davies, from the Oxford Centre for Respiratory Medicine, said the findings showed giving such drugs was essentially ineffective.

"Generally, the use of these drugs should be avoided because they produce no advantage in long-term outcomes and can have side effects."

Some people are allergic to streptokinase and others may experience unwanted bleeding, he said.

But he said in rare cases it might still be beneficial. He said it was also worth investigating other agents to thin the pus.

Dr Richard Russell, consultant chest physician at Wrexham Park Hospital in Berkshire, said: "It's a very important study.

"We are somewhat surprised and a bit disappointed that streptokinase does not appear to help, but it is good to know.

"It might be useful for some particularly nasty thick fluid. You want to remove this muck because it turns to concrete effectively."

Professor Colin Blakemore, chief executive of the MRC, said the study findings would benefit those most at risk of pleural infections - the elderly, homeless and drug users, who are the most susceptible to pneumonia.

"This is an excellent example of how evidence from research contributes to changing clinical practice, with the potential to improve patient care," he said.

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