Antibiotic linked to serious bleeding condition

By Will Dunham

WASHINGTON (Reuters) - An antibiotic often used in hospital intensive care units to treat serious staph infections resistant to other medicines may cause a sometimes-fatal bleeding condition, researchers said on Wednesday.

A study in the New England Journal of Medicine linked the antibiotic vancomycin to a disorder called thrombocytopenia. It is associated with abnormal bleeding and marked by a decrease in blood platelets -- cells that help the blood to clot.

Vancomycin, in use for about three decades, can be used to treat infections in many parts of the body, and is seen as the drug of choice for serious staphylococci infections that are resistant to most other antibiotics. It can have other serious side effects, including hearing and kidney damage.

The study's senior researcher, Dr. Richard Aster of the Medical College of Wisconsin in Milwaukee and the BloodCenter of Wisconsin's Blood Research Institute, said the findings should not reduce use of vancomycin, which he said remains an important life-saving drug for certain patients.

"Only a small fraction who get vancomycin develop this complication," Aster said in a telephone interview. "But it's common enough so that we think physicians be aware of it and be prepared to stop the vancomycin if the platelet count goes down and substitute another antibiotic."

Antibiotics are used to treat infections caused by bacteria.

Patients who doctors think have thrombocytopenia can be tested for a special type of antibody -- an immune system protein that helps seek and destroy invaders like viruses and bacteria -- to see if it is related to medications.

The researchers examined data on 29 patients treated at major U.S. hospitals who tested positive for antibodies related to vancomycin. Three of the patients died after experiencing serious bleeding.

None of 29 had a rise in their platelet counts until use of vancomycin was stopped and use of another antibiotic was started.

The researchers suggested that doctors should have patients seen by a hematology consultant if they experience a low platelet count while being treated with vancomycin.