"After a stroke many patients are given the clotbusting intravenous drug alteplase but another drug may be more effective Australian researchers report. Among more than  stroke victims TNKase tenecteplase was about twice as effective as alteplase in restoring blood flow to the brain and it also resulted in less disability the scientists found. Tenecteplase is likely to become the preferred medication for clotdissolving in stroke patients said lead researcher Dr. Bruce Campbell head of the stroke department at the Royal Melbourne Hospital in Parkville. It is likely to change stroke treatment guidelines and clinical practice. Campbell said tenecteplase is more effective than alteplase because of differences in the enzymes in each drug.  Although both drugs work in the same way tenecteplase is better at attacking and dissolving clots and more resistant to factors that inhibit the breakdown of clots he said. For either drug to be most effective it needs to be given as soon as possible after a stroke occurs. In this study patients were given the drugs within . hours after the onset of a stroke Campbell said. Although tenecteplase appears to be more effective for stroke patients its not approved for that use in the United States according to Dr. Rohan Arora director of stroke at Long Island Jewish Hospital in Forest Hills N.Y. In  the U.S. Food and Drug Administration approved tenecteplase for use after a heart attack Arora said.  Tenecteplase is being widely used in developing countries such as India he said. One reason is its cheaper than alteplase. In the United States tenecteplase costs about  versus alteplase which costs  Arora said. In addition tenecteplase is easier to give requiring only a single injection while alteplase requires an injection and an IV drip he added. Arora explained that tenecteplase is not widely used in the United States for heart attack patients because these patients are typically treated with angioplasty or heart bypass surgery. For the new study which did not receive drug company funding Campbell and his colleagues randomly assigned  stroke patients to either alteplase or tenecteplase before surgery to remove clots. The researchers specifically looked to see which drug was better at restoring blood flow to clotblocked blood vessels in the brain and which drug resulted in patients having better outcomes. The investigators found that  percent of the patients treated with tenecteplase had more than  percent of blood flow return to the brain compared with  percent of those treated with alteplase. Patients treated with tenecteplase also had better functional outcomes after  days than those given alteplase the findings showed. Bleeding into the brain the most serious side effect of either drug occurred in  percent of patients regardless of which drug they received Campbell said. The report was published April  in the New England Journal of Medicine.  More information For more on stroke visit the National Stroke Association http_BwE. SOURCES Bruce Campbell MBBS Ph.D. head stroke department Royal Melbourne Hospital Parkville Australia Rohan Arora MBBS director stroke Long Island Jewish Hospital Forest Hills New York April   New England Journal of Medicine"